Introducing v Ray

8/20/2019 Introducing v Ray

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ZIP ARCHIVE PASSWORD

SherbetLemoncase sensitive

Project files can be found at

http://www.thec4dvault.com/down/vrayguide.zip



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TeC4DVault(.com)

TeC4DVault.com was created by Stuart Lynch and provides Cinema 4D training, resources and sampfiles or the C4D community. Stuart is a veteran Cinema 4D user with over 10 years o proessional exprience in the industry and several years providing instructional inormation to intermediate users.

Tis first in a series o new short instructional pd ’s is aimed at providing the user with enough inorm

tion to digest without becoming overwhelmed. It highlights the backend o VRay and relates the impotance o understanding the settings that make VRayForC4D one o the best render engines around.

Over the coming months, TeC4DVault pd booklets will cover a wide variety o topics, providing a rand reliable way to learn Cinema 4D.

“I hope you enjoy this first addition and learn a thing or two about VRay in the process. Tanks or readin

Stuart Lynch

http://www.project1media.com

Please make a minimal donation to keep the resource alive.*See Donate section at www.thec4dvault.com



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It’s time to turn our C4D shot into a VRayscene. First activate VRay in theRender Settings - figure 1.4

figure 1.4

You’ll notice now a new VRay Bridge Optionfigure 1.5 has appeared or VRay on the lef

hand side

figure 1.5

Clicking the VRayBridge option will reveal

the many VRay bridge parameters gearedtowards the final rendering setup.

Next click on the tab that saysIndirectIllumination figure 1.6 and check the first box that saysGI ON figure 1.7

figure 1.6

You’ve now successully activated VRay anand activated GI.

Feel ree to test the render.

figure 1.7

figure 1.8

Now that you’ve witnessed the true powerVRay, you might want to take it to the nexlevel.

Right click the light object in the ObjectManager and scroll down to the VRay tagFrom the list, you’ll want to add a VRayLitag. figure 1.8.

figure 1.9

Te inormation required to manipulateVRay lights specifically is now contained the VRay light tag or uture reerence. figu

1.9 You can double click this tag at any timto retrieve this set o parameters.



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Te VRayLight tag contains a lot o impor-tant unctionality and we’ll become amiliarwith all o the options as we progress.

For now, our intention is change the targetspotlight to become a Sun light with aPhysicalSky

In the option Light type figure 1.4 Change roma Spot light to an Infinite light.

Also check Enable shadows

figure 1.10

Te light now is as it suggests, an infinitelight and not yet a Sun Light. In order or thelight to become a Sun Light we must clickthe Sun Light tag and make a ew adjust-ments

figure 1.11

In figure 1.11 I have checked the boxes PhysSun and Physical Sky .

A test render figure 1.12 will now reveal a roilluminated by the physical qualities o thesun and sky together.

Focussing on the details o the render, it’spossible to notice that there’s a slight flaw the accuracy o the lighting.

Te sunlight that enters the room looksoverexposed, yet the subsequent light all-off is too dramatic and occurs too quickly

Meaning, the rest o the room is too darkwhen compared to the intensity o the sun

Maybe it’s that the scene needs a fill light perhaps we’ve missed the more GI ‘bouncoption, afer all it’s an interior scene.

Not so ast!

Te solution in Color Mapping

figure 1.12



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Color mappingo make a point stick with his students, my college instructor would occasionally use proanity.So let me say that using Color Mapping in your workflow will ofen save your ASS! Tere are plenty o headaches to come, trust me, but with this simple workflow you’ll avoid blown outlight sources that can make or break a render.

It’s a straight orward concept to understand when illustrated with this amazing set o renders.

In figure 1.13 Te area light in this simple room appears to give off the correct light intensity andilluminates the portion o the room closest to camera. But at the source, the light appears ‘nuked’

In figure 1.14 I we dial back the lighting intensity a little, the light at the source appears to have corrected

itsel, but at the expense o less light reaching the back o the room.

figure 1.15

figure 1.13 figure 1.14

In figure 1.15 the light intensity is restored to the brightness o figure 1.13, color mapping is applied and thelight adequately reaches the entire space. Balance is accomplished.





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It wouldn’t be air to offer you thissolution without some idea o what’shappening behind the scenes. Afer all, youdid buy the book rom a desire to learn.

So i we apply the ‘Indoor’ settings rom theguidelines on the previous page, we can draw

comparison to the original Sun/Sky render.

figure 1.17 is the original without color map-ping applied (Gamma 1.0)

figure 1.18 in exponential mode with the guide-line values (3.6/1.8/2.0) (Gamma 2.0)

figure 1.17

figure 1.18

In figure 1.17 we have the issue where the sulight is not illuminating the scene correctl In figure 1.18 the samples illuminate the shocorrectly and the light intensity is well balanced.

Te difference lies in the mode Exponen-tial, this prevents colors rom becomingtoo burned out and bright. It’ll saturate thcolors as they reach too high o an intensi

Te darkness multiplier value increase to indicates that the original output o grey/blue will have be multiplied by 3.6, givingrise to the additional light and brightnessthe scene.

Te brightness multiplier is increased to 1Which indicates that although the exponetial value has reduced overall brightness, can still be multiplied to compensate or tdip you see in figure 1.19.

You can consider it a compromise.

In figure figure 1.19 the brightness multiplie

is being lef at its deault value o 1.0 and tsunlight would be too low in its intensity.

figure 1.19



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In VRay it’s important to use as accurate ameasurements as possible.Tis basic cube is 500cm x 200cm x 800cmand represents our small bedroom. figure 2.1

Chapter 2: Te test sceneIn this chapter we’ll begin with a quick scene and will introduce the Physical Camera.

figure 2.1

In igure 2.2 I’ve added 5 segments to the Xside o the model. Edit the model (hotkey C)

and move the editor camera inside o themodel.

figure 2.2

With the camera inside the model, select polygons and reverse normals so that theyacing inwards. (hotkeys U~R)

figure 2.3

Selecting two aces as shown below figure 2

Use inner extrude (hotkey I) and extrude (ho

D) to create two window openings.

Here you could split the glass geometry olater (hotkeys U~S) or simply delete the twopolygons.

figure 2.4



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Switch to the point tool and rom the attributes manager uncheck ‘Only select Vis-ible Elements’

figure 2.5

In the op viewport select the polygons thatmake up the ront window and rear wall.Drag to the lef as in figure 2.6

Repeat the process or the Right window as

shown in figure 2.7

figure 2.6

figure 2.7

Returning to the editor view, raise the lowportion o the windows up slightly. figure 2

figure 2.8

Select all the polygons on the floor plane

extrude down slightly to create room or athin moulding eature figure 2.9

Select all ceiling polygons, perorm a slighinner extrude and then a regular extrudeupwards. figure 2.10

figure 2.9

figure 2.10



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figure 2.12

In figure 2.12, extrude the ceiling polygons tomatch the moulding extrusion.

Perorm a simple select loop command withthe polygon tool (hotkey U~L) figure 2.13 andExtrude slightly at 91°

Don’t be concerned i your shot is nothinglike mine. I your scene has two openingsorgive you.

Moving on.

figure 2.14 - ‘est render or illustration purposes only’

Select the wall polygons in between the win-dows and extrude. figure 2.11

figure 2.11

figure 2.13



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Find a place where you’re happy with the viewport representation o your scene andadd a regular Camera.

figure 2.14

‘Roughing out’ the lights

Add a arget Light and position yoursel inthe top view, try to find a placement or thetarget light where you would like the Sun toexist. figure 2.15

figure 2.15

Select VRay as your primary render enginein RenderSettings and as in the earlier ex-ample, check GI on in the IndirectIllumina-

tion tab.

Add a VRay Light tag to your arget light,check enable shadows, change rom spotlight to infinite light. In the SunLight tabactivate the Physical sun and Physical Sky .

Returning again to the editor view andensuring you have you camera selected. Ryour first render. figure 2.16

figure 2.16

Clearly not enough light entering the roomon this angle. Tis issue o balance is morprominent than in my initial examples.

It’s time to apply Color Mapping to bring room to lie. figure 2.16

figure 2.17

REMINDERFOR INDOOR SHOS.

ype: Exponential (some preer HSV exponential)Dark Multiplier: 3.6Brightness Multiplier: 1.8Gamma: Between 1.8 - 2.2LinearWorkFlow - Check to ON

A small improvement.



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Bringing the shot to life.

From the Material Manager add a new VRayAdvanced Material to the scene. figure 2.18

So ar we haven’t included any materials in our scene. VRay responds to color change quite dramaticalas does color in the real world. I we add a tiled wood texture to the floor, the bounced light rom thewood and its color values will have an affect on the scene. Let’s explore urther......

figure 2.18

Assign the new VRay Ad- vanced Material to your cubeobject in the OM (objectmanager). figure 2.19

I’ve named my material ‘base’figure 2.19

Double click the Material ‘Wood’In the Diffuse Layer - exture map slot.Load a wood tile texture figure 2.21

Create a second VRay Advanced Materialand change the name to ‘wood’

Select all floor polygons and drag the ‘wood’material over the polygon selection figure 2.20

figure 2.20

figure 2.21

In the OM select (click) the wood materiatag. In the Attributes Manager, change theprojection mode rom Spherical to Cubic

Using the texture axis tool and the scale tofigure 2.22 Scale the wood texture to fit yourscene.

figure 2.22



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Running a new test render, notice how thewooden floor is affecting the lighting in therest o the scene. figure 2.23

figure 2.23

Make a ew adjustments to your camera po-sition and to the SunLight and try to balanceboth lighting direction and composition.

figure 2.24

figure 2.24

In this next phase o scene creation, we’llstart blocking out some objects with simplegeometry to get a better eel or composition.

Place Cube primitive objects and positionthem where the bed, side tables and cabinetwould potentially be.

Te presence o more white objects haschanged the dynamic lighting o the sceneonce again. figure 2.25

figure 2.25Adding some additional materials with variations in color (preerably chosen to represen

how you imagine your scene) we’re able to improupon the overall eel o the shot. figure 2.26

figure 2.26

With all o these geometry additions youmay have noticed that the light in the roohas taken a significant dip in brightness.On the next page we’ll discuss the PhysicaCamera and how to implement photograp values in order to restore the balance.



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Introduction to the Physical cameraTe Physical Camera in VRay allows us to reproduce the parameters o a real world camera.o improve our scene without urther adjusting the Color Mapping or the deault lighting intensity o Sun, we’ll implement the Physical Camera and make use o its eatures such as ISO and FStop.

From the OM select your scene Camera,right click and apply a VRay Physical Cam-era tag rom the VRay Bridge ags submenu.figure 2.27

figure 2.27

I you test a new render you would noticethat no significant changes have occurred.

Tough the deault settings o the VRayPhysical camera provide a similar result,they differ greatly rom a camera that has noPhysical properties.

Te proo is in the numbers.

In the VRay Light tag under the Sun light parameters you’ll see two separate values.

Intensity multiplier or Phys Cam : 1Intensity multiplier or Std Cam: 0.037

Te sun intensity is divided by exactly 270to work at the deault value o the standardcamera.

It’s good practice to use the Physical cameor all o your scenes.

We’ll look more closely at comparisons inlater chapter, or now we’re occupied withincreasing the exposure values o our scenwithout making any adjustments to lightintensity.

Click the VRay Physical Camera tagUnder the ab - Lens parameters.

Scroll down to Film ISO and change the value rom 100 to 400

A test render produces this result figure 2.28

figure 2.28

figure 2.26 ‘Old result or comparison’





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Chapter 3: Introducing VrayBridge render settingsQuality is very important when we think about final renders, but this shouldn’t always come at the coso lengthy render times. Trough exploring VRay’s render settings we’ll learn to tweak the parameters order to get the best results in an optimal amount o time.

In this section we’ll optimize the VRay Render Settings and then explore the method behind the mad-

ness. Open the example bedroom.c4d open rom www.thec4dvault.com and lets begin.

figure 3.1

From the ab Indirect Illumination (GI) select ‘01_IR-LC_very very ast’ rom the GI

Preset list

IR reers to Irradiance MapLC reers to Light Cache

In the Primary and Secondary bouncesyou can see the two modes being selected.With this setup the Light Cache will be cal-culated first. figure 3.3

figure 3.2 figure 3.4 ‘Te amiliar Light Cache calculation’

figure 3.5

At these low settings rendering with LightCache as both a first and second bounces

as with figure 3.5 would produce some oddsplotchy results.

Although with the correct values, this technique is equal to Unbiased rendering.GI Preset 19_LC_LC_PP_unbiased is seup to render in this way.

Te Light Cache is an approximation o thglobal illumination in the scene. figure 3.4

figure 3.3



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Afer successul completion o Light Cach-ing, the Engine then begins computation theIrradiance Map.

A simplified explanation o the Irradiancemap is to imagine a point cloud that origi-nates rom the Camera and projects out-

wards into the scene.

In figure 3.6 I’m using a VRay resourcecalled IMapViewer.exe. With this we’re ableto view the resulting IR map in its raw orm. From the camera perspective in the bottomlef corner, it’s quite easy to visualize the jobo the Irradiance map. Tere are no samplesoutside o the Camera view and so we can

conclude, it only samples what it needs tosee.

figure 3.6

figure 3.7

Te simple scene below is the resulting figure

3.7 render rom the above calculation.

Te more refined the Irradiance map settare, the better it is able to assist in renderismaller details. Tis also comes at the cosrender time.

Objects such as walls and floors require vlittle IR sampling, but a detailed ornamen

on a table needs more refined samples toreach the tight spaces.

Providing adequate coverage is much lesso a struggle than it may seem. VRay comloaded with presets that provide an excellstarting point in most cases.

figure 3.8

Te DMC Sampler figure 3.8 is the VRaycontrol Room. Tese 4 values basically de

termine how VRay uses its adaptive sampwhich I’ll explain later.

Te engine itsel uses deterministic MontCarlo sampling (DMC), which is a highquality approximation GI algorithm. Tebetter the settings, the more reliable and acurate that approximation becomes.

It’s not imperative that we learn exactly ho

the backend o VRay works. What’s impotant is that we understand how these vastamounts o values will affect our end resu

We’ll need to break them down a little inorder to make sense o them.



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Back to the DMC sampler, add the valuesrom figure 3.10

figure 3.10

Adaptive amount will be lef alone.Minimum samples have been reduced rom8 to 4Noise threshold was in an okay place with

0.01, so we won’t touch that either.Global Subdivs multiplier is set 0.5, downrom 1.

In the tab Indirect Illumination (GI) clickthe Irradiance Map arrow to reveal more tings figure 3.11

change the Hemispheric SubD

Anti Aliasing ( AA) is another important ac-tor in determining final VRay render quality.

Te Adaptive DMC Anti Aliasing mode figure

3.9 and the DMC sampler figure 3.8 are tiedin very closely, especially when comparedto other Anti Aliasing techniques like the

Adaptive Subdivision sampler

figure 3.9

figure 3.11

figure 3.12

figure 3.12

For Hemispheric SubDivision enter the value: 30For Interpolated samples enter a value o:

We can ignore the other settings or now.

figure 3.13

Still in the tab Indirect Illumination (GI)

click the Light Cache arrow figure 3.11

In here we’ll simply be changing the SampRatio rom 1/2 to 1/16 figure 3.13



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Finally under the Options tab un-check theGlossy Effects to prevent any blurry reflec-tions rom calculating figure 3.14

figure 3.14

Now we can run our first preview qualityrender at ultra ast speed.

figure 3.15Te result is awul, yet it took only 12 sec-onds to render at 1280x720.

Tis very low setting is a perect place tostart rom i you’re blocking out the sceneand need to make quick decisions.

We’ve barely scratched the surace o thisnew inormation and I have you dialing innumbers that probably make no sense to ywhatsoever.

My instructional method is to teach throuexample. Once you’re amiliarized with thprocess it will start to become second natu

Yet that is only part o the equation.

It is also important to have a basic under-standing o why each value works the waydoes.

In this next section we’ll adjust or a finalrender a along the way I’ll point out somethe method behind the madness.

figure 3.16

I your render happens to look as it does ifigure 3.16, it would be because you haven’t yapplied Color Mapping. Not mentioning ithis was an intentional test.



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Creating a higher quality renderReload the example bedroom.c4d

Attempt this without illustration (please)

#1 In the tab Indirect Illumination (GI) se-

lect ‘03_IR-LC_medium’ rom the GI Preset list and check the box GI On

#2 In the Irradiance Map sub menuMin Rate: -3Max rate: -1Hemispheric SubDivision: 55Interpolated samples: 15 Leave every other IR setting alone

#3 In the Light Cache submenu

Un-check Override LC SubdivisionSubdivision: 1000 Scroll down a little toReconstruction parameters

Un-check Enable LC retrace

#3 In DMC Sampler tab

Adaptive amount: 0.85Noise threshold: 0.01Minimum samples 8Global Subdiv multiplier: 1 #4 In the Antialiasing tab

Antialiasing type: DMC samplerFilter on: Check Filter type: Catmull-RomMin SubD: 1Max SubD: 5

#5 Color Mapping tab

ype: Exponential (some preer HSV exponential)

Dark Multiplier: 3.6Brightness Multiplier: 1.8

Gamma: Between 1.8 - 2.2LinearWorkFlow - Check to ON

#6 ime to render.

figure 3.17

My render time at 1280x720 on a 6 core

I7-980x (running at 4.4ghz)was 1 min 48 secon For a scene with Global illumination that’not a bad time.

But was the result ready to send to a clien Well, aside rom the act that the scene ispretty bad to begin with, I’d still have to gowith “no”.

Tere’s artiacting issues in a couple o aretoo much noise in the wood and black glometal and it needs a little more.

It eels close but it could use a little more tsell it as final.



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Indirect Illumination - Irradiance map

empting as it may appear to ignore this section and rely upon VRay’s preset values, I would recommeagainst it. Presets only solve hal o the equation, they have no affect on AA or the DMC sampler andthey’re not intended to provide a complete setup or your scene.

Instead see the presets as a good starting point. Te Medium quality preset is sufficient or most projectand only requires a ew minor adjustments to bring it up to speed.

When rendering a GI shot in VRay, theengine requires two solutions to produce ac-curate GI results. Tose are the Primary andSecondary bounces.

In figure 3.18 I’ve turned off secondary bounces

and lef the Primary bounces as: Irradiancemap.

With only one GI engine actively calculating,a correct GI solution has not been possible.

Tis is visible as the dark areas in the image.

Each o the approximation methods has itown very specific parameters.

Te IR map (IR map - Irradiance map) has manoptions or the management o correctlycalculating samples, sample accuracy and

tail enhancement. It also has a section useexclusively or animation,.

Te first two parameters you come across Min rate and Max rate. Tese settings relato the size o the IR map calculation.

Te Min value “determines the resolution the first GI pass”. Te Max value determinthe resolution or the last GI pass.

A Max value o 0 would imply that theresolution o the last GI pass is equal to thdimension o your scene resolution.

A value o -1 is equal to hal the resolutionthe dimensions o your scene resolution.

A Min value o :-4and a

A Max value o: 0,

....would create 5 passes during the cachinprocess. ( -4, -3. -2, -1 and 0)

Te Max value 0 is typically not needed oless complex scenes.

figure 3.18

So ar we’ve used only two o the fivepossible GI engines in these slots. Te preset values highlight other combinations, thoughthe IR and LC is our ocus or the time be-ing.

As Irradiance map is our primary bounce,we’ll introduce its settings first.



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You could ask why not just have a Min valueo -1 and a Max value o -1? Or a fixed value?

Te smaller values in the Min setting (-4 or

example) are important or sampling the biggerdetails (walls etc). Te larger values in Max (-1or 0) are or sampling the finer details.

You would rarely encounter a need to use apositive value like 1 in the Max setting. I itoccurs to you to do so, it would be wise tolook elsewhere beore concluding that this isthe solution to your rendering woes.

Min and Max however, are only part o thesolution.

In figure 3.19 the low settings I’ve deliberatelychosen are creating very obvious splotches.Tis suggests that are settings are way off themark and need to be re-worked.

A Hemispheric SubDivision is part o theradiance map and is used to determine “thquality o individual GI samples”. Relatingonly to the samples o IR map in this case

We can look here to improve upon our IRmap caching process. A good starting pla

when attempting a final render is around 50 mark.

Values upwards o 150 are not unheard oproblematic renders, though typically youfind that 50-80 is adequate.

Interpolated samples reers to the interpotion o the IR map samples. Tis calculatilook towards the range o existing data an

attempts to refine that process urther.

With this setting - oo high a value is likelto blur the solution, oo low and the sampwill receive no interpolation.

So we can determine that some Interpolatsamples are necessary.

o compliment the Hemispheric SubDivi

sion, a value o approximately 15-30 is usually always sufficient.

figure 3.19

Refining the IR map settings is how weprevent splotches and other inaccuracies. Itensures that this approximation method (our

primary light bounce) will provide enoughsamples to assist in a flawless final render.

Note: Over estimating the values can cre-ate unnecessarily long render times. Underestimating causes artiacting. (Not to beconused with noise)

figure 3.20

Look to the next page or some compariso



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In all o the above examples Hemispheric SubDivision has a value o 50

In figure 3.21 the Interpolated samples value is 1, which at close inspection is too ew samplesIn figure 3.22 the Interpolated samples value is 100. At this value the samples tend to become blurred.In figure 3.23 the Interpolated samples value is 20. Tis is practical amount or most renders.

At this scale it is perhaps difficult to see a huge difference. Also any remaining noise issues you’re seeinwould then be an issue with the DMC sampler and not the IR Map.

figure 3.21 figure 3.22 figure 3.23

Tere are clearly other settings in the Irradiance map parameters, yet in the interest o not becomingbogged down with too much input, I’ll only briefly highlight their usage.

o the lef o the Min/Max rates lie the Intensity Treshold, Normal Treshold and Distance Treshold

Tese settings reer to individual sensitivities to light intensity changes, surace normal changes andchanges in the distance between suraces. I would leave these values alone and let the provided preset

values guide you until you become more amiliar.

Tere are occasions with objects such as ‘thin blinds’ where adjustments to these settings will benefit yrender.

In the Detail enhancement section are a couple o additional parameters.Tis unction as the name implies creates additional detail (to small detailed objects, not really useul in a typical sce

Utilizing this process will orce the GI algorithm to compute with Brute Force GI in places that are dificult or the IR map to reach.

When using this unction it is ofen necessary to consider lower overall IR Map settings.With this option checked we’re dependant upon Detail enhancement to enhance our render, the remaiing settings would thereore only need to made be suitable or coverage o the larger objects.Note: Tis is because large objects such walls/ceilings typically get adequate coverage rom ewer samples.

In my proessional career I have used the Detail enhancement unction no more than 3 times.



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Indirect Illumination - Te Light Cache.

Te light cache (once again) is the approximation o global illumination in the scene.

Spot3D.com “Te light cache is built by tracing many eye paths rom the camera.”

figure 3.24

I have to admit the first time I saw thismenu, I elt a lot less threatened by it than Idid the Irradiance map options.

In our current IR - LC setup we’re depending

on the Light Cache portion o this solutionto computer the secondary bounces.

In figure 3.24 the Overide LC subdivision box ischecked by deault.

Te value inside the samples ratio (drop down

menu) and the Subdivision amount (greyed out

box) differ only in mathematical approach.Tey both determine how many paths are

traced rom the camera.

Un-checking this box and manually insert-ing your own value is recommended, espe-cially i the secondary bounces require moreattention.

Te number o paths traced rom the camis the square o the subdivision value. 100equals 1 million paths. 2000² is 4 million 10,000² is 100 million.

Te Samples Ratio values are based on theresolution o your scene. In the case o the1/1 setting in a scene that’s 1280x720, theLight Cache would produce 0.9 million

paths.

figure 3.25

In figure 3.25 I used a Sample ratio o 1/1 at1280x720, implying 921,600 samples.Te light cache took 28 seconds to compu

figure 3.26

In figure 3.26 I used a 960 samples in theSubdivision box. 960² = 921,600 samplesshould come as no surprise that the calcultion took exactly the same amount o time



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Tere are some instances where you’ll needto go beyond the 1/1 Samples ratio amountand manually enter Subdivision values.Tough 1/2 is quite sufficient in most cases.

It is imperative to use a higher value duringanimation, but rare to exceed 4000.

With scenes outside o the typical PhysicalSun/Sky setup, where perhaps we’re using anabundance o light sources . Te subdivision values will benefit rom a boost.

figure 3.27

We’ve covered the essentials and I’ll providea very brie explanation or the remainingsettings.

Sample size determines the spacing osamples in the light cache. (Leave alone or now)

Passes calculates the light cache separatelyon each thread o your cpu. (Useul or animation)

Store direct light. Tis option stores andinterpolates direct light. Tis can be useul iyou’re using and IR - LC setup.

Use camera path. Tis is or tracing the Lightcache along a camera path and is beneficialor animation.

Adaptive tracing. Stores additional inor-mation about incoming light or each lightsample.

figure 3.28

Reconstruction parameters. Tese parameters control how the light cais used in the final rendering, afer it hasbeen calculated.

Prefilter Checked on - Prefilter will be usePrefilter is applied once the cache is com-puter or loaded rom disc.

Prefilter samples More prefilter samplesequals a more blurry and less noisy cache

Filter type. Tis is or tracing the Light caalong a camera path and is beneficial oranimation.

Use light cache or glossy rays. I this optiis on, the Light Cache is used to computeglossy rays as well normal GI rays.

Tis option can speed up rendering o scenethat have blurry reflections by a significantamount.

Enable LC retrace. Tis option assists VRain preventing light leaks at the expense oslightly increased calculation time in the IMap.

Retrace threshold. Tis value can be used conjunction with ‘use light cache or glossrays’ to help VRay dynamically decide whand where to use the Light Cache.



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Te DMC SamplerHaving covered two o the possible GI engines and how their individual passes contribute towards thequality o the final render, we need to talk about the big guns! Te DMC Sampler.

You can think o the DMC sampler as a global quality control.Tis group o 4 settings play a very important role in the rest o the workflow.

figure 3.29

During render time, the DMC sampler islooking out to your scene or additionalsamples.

Tese rays are computed in such a way thati the values are too low, they will produce anoisy result. figure 3.30

figure 3.30

Values rom almost every part o the renderengine are coming in through this channeland being processed here.

Whenever you create a light, a blurry reflec-tion, use Depth o field or Motion Blur (toname a ew), you’ve actually been providing theDMC sampler with more samples and inor-mation about the scene.

Looking at an Area light’s parameters (VRa

Light tag) , it reveals that the DMC sampler wbe receiving 8 Subdivision samples rom thlight source. figure 3.31

Te actual amount o samples, is the squaro the subdivision value / 8² subdivisions = 64samples

figure 3.31

Te DMC Sampler can look at a series othese samples and determine that it hasenough inormation to not use them all.

Tis is the role o the Adaptive amount.

Let’s imagine the DMC sampler sees 100samples or the entire scene. I we chose anadaptive amount o 0.8, the DMC samplerwill always use 20 o those samples. Teother 80% will be considered internally bythe engine, but not necessarily used.

Control over this unction is decided by th“Early ermination Algorithm”



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With an Adaptive amount o 1, we hand overcontrol o all o the samples. (Fully adaptive)

With an Adaptive amount o 0, All 100samples will be used without considerationor the “Early ermination Algorithm”. (Notadaptive)

In most cases, the deault value o 0.85 orthe Adaptive amount is more than sufficient.

At 85% adaptive, this may seem like we’releaving too much to chance, giving too muchcontrol to the DMC sampler. But VRayhandles the process very smoothly and it’snot ofen necessary to go below 70% (0.7)

Noise Treshold.

Te Adaptive process communicates directlywith the Noise Treshold amount. Tis valuedetermines the amount o noise that is ac-ceptable beore it can tun its attention to thenext pixel in the calculation.

figure 3.35

figure 3.32 Noise threshold has a value o 0.0figure 3.33 Noise threshold has a value o 0.1figure 3.34 Noise threshold has a value o 1

A value between 0.01 and 0.004 is a goodrange or final renders.

When the Noise Treshold is 1, the DMCsampler is satisfied that the desired amouno samples has been met while it’s still producing a very noisy value. Tis amounts tan incredibly ast, but noisy render.

Te DMC sampler requently needs moresamples rom the external elements that adifficult to compute.

A metal material that has blurry values(Glossiness subdivs ) such as Brushed steel ofen require more samples to achieve noireduction and a quality result.

Instead o trying to compensate or this inthe DMC sampler, we would simply increthe Glossiness Subdivs value in the speculchannel o the Vray Advanced material to value higher than the deault 8. figure 3.35

figure 3.32

figure 3.33

figure 3.34

Similarly, a single Area light that clearlystands out rom the others as having toomuch visible noise, would also benefit rosending more samples to the DMC sampl



Page 34

When a single object causes an issue, it’s im-portant to look at it’s individual subdivision

parameters to resolve.

It would be a shame to spoil a good balancedrendering solution and shoot or an overallincrease in quality on account o one prob-

lematic object. Tis wouldn’t be a practicalway to work.

Looking again at figure 3.29 we have 2 settingsremaining to talk about, and both o them atthis point should be easy to comprehend.

figure 3.36

Minimum Samples

Min samples equals the minimal amount osamples that the DMC sampler will computebeore terminating the algorithm.

Note: Te deault 8 is once again squared

to imply 64. It also intentionally matchesthe deault number or all subdivision based

parameters.

Global Subdivs multiplier.

I an overall quality boost is required orevery subdivision based parameter , this is agood place to dial in some numbers.

Te deault value o 1 implies that every value will remain the same as the input value(or example: Glossiness Subdivs: 8)

A increase to 1.5 would provide a 150% in-crease to all o these values. (Increasing the:Glossiness Subdivs: to 12)

I’ve introduced you to 2 GI engines so athe combination o which enables VRay tprocess your render.

Te IR + LC method is a popular choice aas an introduction to these practices wasworth highlighting them side by side.

Some other useul combinations are highlighted in the presets.

I.e; Lightcache +Brute orce / IR radiance Map + Brute orce.

Brute orce computes every single shadedpoint separately and independently o othpoints, (while other approximation methods conside

their neighbor in determining calculation). Whilehighly accurate this method can also be vslow.

Te subdivision parameter here will alsotalk to the DMC sampler in the same waydiscussed earlier.

Ray depth controls the number o bouncethat will be computed, but is only availabli Brute orce is chosen as a secondary GIengine.

Photon maps are occasionally useul or interiors scenes, but this is an older methodapproximation and I typically avoid it.

Spherical harmonics is not yet properlyintegrated into VRayForC4D and should avoided.

Brute force, Photon maps, or

Spherical harmonics.



Page 35

I’m certain you’re all amiliar with the practice o using Antialiasing in your scenes.VRay eatures 3 types o image samplers (antialiasing methods) and each one differs slightly in approa

We have the Fixed rate sampler, the Adaptive DMC sampler and the Adaptive Subdivision sampler.

Choosing the right image sampler is determined by the individual scene and there are different considations or each approach.

Antialiasing

Fixed Rate sampler figure 3.37

With this method, the sampler takes a fixedrate o samples per pixel. Te subdivision value is squared as with other subdivisionparameters. 1² =1 / 2²=4 / etc A value o 4 would indicate that 16 sampleshad been taken per pixel.

Tis sampler is simple and predictable in abroad range o antialiasing tasks, but the na-

ture o a fixed sample can equal slow peror-mance in some cases.

Note: Tough not be ignored, I would recom-mend one o the other two choices based onmy experiences with Fixed rate sampling.

figure 3.37 Adaptive DMC sampler figure 3.38

Tis sampler takes a variable number osamples per pixel based on a Min and Ma

rate.

It can also use the threshold set in the DMsampler to determine i more samples areneeded. (vs manual entry in Treshold amount)

Tis method is best or scenes that use a loo blurry effects and is the preerred imagsampler or DOF and Motion blur effects.

Note: It is rare to have to increase the Minlevel higher than 1, other than scenes that a problematic.

Using Show Samples is a way to preview tantialiasing setup prior to final render.

figure 3.38





Page 37

I you want VRay to create high quality images that don’t take orever to render, then we already have othing in common.

o achieve this, I requently tell my students that the best starting point is rom lower/medium qualitypresets. From here you’ll be able to discern what part o the render needs your attention the most. Is itsplotches on the walls? Ten look to the IR map. Or are the walls fine and it’s some nuisance ornamentwith a bump map giving you grie? Ten look to it’s material setting, the nearest light source, or bettermanage the antialiasing settings.

Tat may seem like a common sense approach, but i I got a dollar or every time somebody sent me ascene where they’d randomly entered 0.001 in the Noise Treshold to resolve a simple issue, I’d be rich

Tat value may well have fixed the issue, yet they inadvertently made the rest o the scene more complcated than it needed to be. On inspection it’s usually obvious that they were only trying to improve upa couple o small problems.

Similarly there’s a list o preset values known as “Universal VRay 1.5 Settings” that people rave about.You can see the appeal right away, although i you use these settings be open to the possibility o waitinaround or a long time.

It’s my hope that I explained this process with relative clarity. I you do have any unresolved questions theVRayForC4D manual offers very precise examples o why each setting perorms the way it does.

Wrapping up



Page 38

Chapter 4: Vray’s materials

Whatever your choice o render engine it’s good practice to have a test scene or trying out materials.In this chapter we’ll work with such an environment and introduce Vray’s BRDF material system.

figure 4.1

Open the scene file test_stage.c4d figure 4.1

figure 4.2

Te scene uses three area lights and somebasic geometry, it also renders very quicklyor ast eedback.

Create rom the materials manager, a newVRayBridge - VRay Advanced material

A VRay advanced material has ar more

options than a standard C4D mat. Te vasmajority o materials you’ll set up in VRayare relatively straight orward, though witthis much flexibility, there’s a lot o room complexity and creativity.

Te material editor eatures many settingsthat you’re probably already amiliar withDiffuse (color), Bump, Material weight (alpha), Luminosity layer (Luminance) an

Specular layers (a mix o C4D’s reflectionand secularity settings), Reraction layer(transparency)

figure 4.3





Page 40

For our first material, lets activate a singleSpecular Layer and leave everything as de-ault. Apply the material to the sphere objectand perorm a quick render test. figure 4.6

figure 4.6

In the setting Specular Layer ransparency ,

change the amount to 50% and test again.

figure 4.7

Te reduction o transparency has allowedor more o the reflection rom this layer toshow. figure 4.7

For the next stage o this material test, addanother Vray advanced material and in the

diffuse channel only, add a blue color. Applythis new material to the cube object.

Now returning to the first materials Specularlayer. Scroll down to reflection glossinessand add a value o 0.8. figure 4.8

figure 4.8

figure 4.9

A rendered results should now show a melike material that’s been processed with boake specularity and glossy reflections. figu4.9

figure 4.10

At the top o the Specular layer settings isoption or Specular ype. Change this roPhong to Ward. Te result should now loolike figure 4.10



Page 41

Each Specular ypes computes in a uniqueway and provides different results. Blinn andWard are good choices or metallic effectsand they also render Anisotropic effectsmore accurately.

Back in the Specular layer settings change

the Anisotropy value to 0.5

figure 4.11

Te result figure 4.11 is not quite yet a Brushedmetal, but we’re establishing the workflow inordered to create one.

For the next step, return to the Diffuse layer(remaining within the metal material) and reducethe Diffuse Color - Brightness amount to

20%.

Back to the Specular layer scroll all the waydown to the last ew settings and Check theUse Fresnel box and input 22 or Fresnel IOR (Index o reraction)

You will now notice that the Specular Layerransparency option is no longer available.Tis is because we’re using IOR to determine

reflectivity.

In the Specular color at the top, add a Fresnelshader to the texture map slot. figure 4.12 In theshader settings, reduce the black to a lightgrey. Tis will prevent the scratched suracerom reaching the sphere’s edges.

figure 4.12

Lower the Anisotropy amount back to 0 ain the exture map slot below load in thetexture ‘H_Brushed.png’ rom the texturolder.

Repeat this process as illustrated below infigure 4.13 - while also checking the invert bowhere appropriate.

figure 4.13



Page 42

We’ve provided VRay with enough inorma-tion to produce a semi-realistic scratchedmetal surace. Work can be done in thebump map channel to bring out extra detailsand a lot o time can be spent tweaking the values or a perect result.

Note: Te reason behind the inverted texturemap in the Glossiness reflection is that in real-ity, the deeper the scratch, the more blurry itsreflectivity would become.

Te result in figure 4.14 is ar rom complete,yet you have a good starting point romwhich to experiment urther.

figure 4.14

Using a similar technique in figure 4.15 to cre-ate a Galvanized metal, the differences inblurry values vs more reflective values areobvious.

figure 4.15

You may have noticed that in the Specularsettings I increased the Glossiness SubDivsion amount up to 30.

As discussed in the section on VRay’s DMsampler, this is an example o where thematerial needs to send out more samples

order to be computed with less noise.

Keep in mind that these sorts o materialsare usually quite render intensive.

figure 4.16 ‘VRay Goldman’

In both figure 4.16 and figure 4.17 you can see t vast amount o flexibility available to you the Specular layer channel.

figure 4.17 “Te Weasley’s’



Page 43

Te Diffuse layer

Tere are two Diffuse layers in the Vray advanced material, these are useul or mixing diffuse (color/tture) effects without resorting to separate materials.

VRay Dirt is also accessible through the Diffuse layer. By applying Ambient occlusion at the materiallevel this option creates the appearance o dirt on the surace details o an object.

Te Diffuse layer ransparency option serves two unctions, it is first required to let the underlying layshow (Diffuse layer 2) and is also required to use the Fast SSS shader option (see page 57)

figure 4.18

Open example file scene test_stage2.c4d

Create a new Vray advanced material and applyto the sphere object.

In Diffuse layer 1 check rom the Diffuse op-tions - Use VRayDirt.

Te menu layout will now change to theVRayDirt workflow.

Add a black Color channel to the Occludedcolor slot (rom the drop down menu)

Add an 80% white Color channel to the

Occluded color slot (rom the drop downmenu)

figure 4.19

In figure 4.18 the result has been intentionalenhanced to show the overall effect.

Any color combination can be used toachieve the desired look.

In figure 4.20, I’m using a wood texture as thUnoccluded color and Red or the Occludcolor (Dirt effect).

figure 4.20

‘VrayAdvancedMaterial’



Page 44

Refraction Layer

Te Reraction layer is or the creation o optically transparent materials.

Tis layer can assist in the creation o standard glass, gems, fluids, complex translucent effects, rostedglass and much more. It’s parameters contain options or the accurate calculation o Absorption, Blurr

effects, Dispersion and Sub Surace Scattering.

figure 4.12 - Color enhanced

Open example file test_stage_glass.c4d

Create a new Vray advanced material and applyto the glass object.

Deactivate the Diffuse layer and activate a

Reraction layer.

Check Specular layer 1 without making anychanges.

Render

Without any changes to the deault settings,

the Reraction layer provides us with a glassmaterial with an IOR (index o reraction) o 1.6

Adding a Specular layer to a glass materialis common practice, as glass always includessome amount o reflectivity.

In the Reraction layer look towards theVolume Fog parameters and check EnableVolume.

Leave the Emission color as deault blackand chose a very light orange/yellow or t

Volume Color. Finally increase the amounto 0.3 and render.

figure 4.13


Tis effect has added absorption propertito the glass and it now has the appearancegreater volume.

‘VrayAdvancedMaterial’



Page 45

o simulate rosted glass, we would entera Glossiness value (0.6 in this example) in theReraction layer. As shown in figure 4.15

Variation in the rosted amount can beachieved by using the Glossiness exture mapslot.


Note: Tese effects can add significantly to your rendertime and ofen require additional subdivision values torender accurately.

Te images below contain different exampleso Glossiness effects in the Reraction layer.

figure 4.16 ‘Visa’ product shot

figure 4.17 ‘Go Beyond’

It is also possible to use the SSS parameterrom the Reraction layer to simulate thetranslucent properties o hard wax, honeyplastics and other suraces that depend mon reraction or accurate results.

Te example rom figure 4.19 uses the ollow

ing setup. figure 4.18

figure 4.19

figure 4.18

Note; o speed up the SSS calculation check‘Environment og’ in the SSS parameters. Tstores the light directly in the volume.



Page 46

SSS calculated as part o the reraction layer (as shown on page 45) is an accurate representation o a realworld translucent effect. While it can produce stunning results, it can also be notoriously slow to rende

A much aster approach is to use a VRayFastSSS2 material. Te parameters o which are available as anextension o the standard VRay Advanced material and as a standalone material called the VRayFastSmaterial.

It’s also possible to cheat translucent effects using the Vray2Sided material. (which we’ll cover on page 48)

Te majority o your translucent material needs should be met by the Fast SSS option.

Sub Surface Scattering

figure 4.20

Open example file test_stage_candle.c4d

In this scene I’ve simply added a VRay-FastSSS material to the cylinder shape, madea couple o adjustment to color and added atexture map.

Te result figure 4.20 shows a subtle hint otranslucency.

In the VRayFastSSS material settings, scrolldown to options and change the Single Scat-ter parameter rom to Simple to Raytraced-reractive. figure 4.21

figure 4.21

figure 4.22

Te rendered result is now noticeably diffent. figure 4.22

Te original Simple mode approximatedtranslucency rom the surace lighting alo

Te Raytraced-Reractive mode traces thereraction amount based on the providedIOR.

Also notice that when VRay is computingFast SSS, it’s also adding an additional dar

pass that appears to isolate the transluceneffects.

Tis is a special pass called the Illuminatiomap. It can be controlled in the prepass rawhich is set to -1 by deault. For higher reimages, a value o 0 is occasionally needed

‘VrayAdvancedMaterial’ and ‘VRayFastSSS2 Material’



Page 47

Tis time we’ll use the SSS layer in the VRayAdvanced material to make a semi accurateportrayal o a marble floor.

Open example file test_stage_marble.c4d

Te scene is setup with a marble texture map

and contains only a Diffuse layer.

In the Diffuse Layer change the DiffuseLayer ransparency to 40%. Tis will allowunderlying effects such as the SSS layer tomix with the Diffuse Layer at the inputted value.

At 100% transparency , this Diffuse layer

would no longer render at all.

Activate the SSS Layer and try to match thethree shades o green rom figure 4.24

figure 4.23

figure 4.24

Change the Single Scatter parameter romSimple to Raytraced-Solid. figure 4.21

Te Raytraced-Solid mode will calculate/etimate the Volume inside the object.

Te material is starting to look a little bettbut it’s missing glossy reflections and a bummap.

Activate a Specular Layer , check Use Fresand input a value o 1.6 or the Fresnel IOamount. Next, input a Reflection Glossine value o .095

Activate Bump and copy the Diffuse Layetexture into this channel.

With no real bump inormation, you canincrease the value to 3. Tough this is notpractical approach or most materials.

Te result is ar rom perect, but suffice tsay it created the desired affect. figure 4.25

figure 4.25

figure 4.26



Page 48

VRay2Sided Material

Making a ‘lamp shade’ with the bulb obscured behind a layer o abric (as in figure 4.27) used to be a di-ficult task to accomplish. Fully opaque materials simply weren’t designed to transmit light through thesurace in this way. Adding Diffuse layer transparency (or alpha in C4D) didn’t help matters either, as apercentage o the light would simply pass through the volume.

Te VRay2Sided material solves this old limitation by allowing us to have a ‘diffuser’ in VRay.A diffuser sofens light as it passes through a surace, essentially making it what we call translucent.

Tis material was created to address the need or thin translucent objects like paper, leaves, abrics, diusers etc, but its application can be much more experimental.

In figure 4.27 ‘the lamp shade’ object highlights an example o how this material was intended to work.Illumination rom within the object passes through the material via translucency and displays the resuon the ront acing normals.

Te VRay2Sided material is controlled by two standard diffuse materials (VRayAdvanced material) or theront/back acing normals and a ranslucency color to determine how much o the effect should comethrough.

Te VRay2Sided material in figure 4.28 eatures reflective properties on its ront side. A separate object wa colored pattern light has been placed within the dragon model (via the Luminosity layer) and the resultcreates a glowing translucent effect. Tis behavior looks closer to a reractive SSS solution, but is actuacheated as the light is emitted rom the inside only. O course cheating in 3D is never a bad thing.

In figure 4.29 I’m using the same approach but on a much bigger scale. Tis time I’ve placed uniquely colored light objects within each skyscraper. Te Luminosity layer casts its rays outwards and are intendeto ake the lighting that would have otherwise come rom a traditional lighting solution. Tis was a tesscene, but also a very practical solution or visualizing cities at a distance.


Standalone material



Page 49

figure 4.31

Open example file scene 2_sided_user.c4d

Tis simple setup has an area light, a thinplane object, a couple o props and currentlyno materials. figure 4.30

figure 4.30

I we the render the shot directly, you’ll see

that the plane object is obscuring the light.figure 4.31

Add a VRay2Sided material and apply it tothe plane without any additional changes,and it will now render a simple diffuser. igure 4.32

figure 4.32

Te light has now penetrated the object asdetermined by the parameters in the VRa2Sided material.

Leaving the ront and back side options othe VRay2Sided material ree o supportinmaterials was a deliberate move. It illustra

that in the absence o a material channel,the VRay2Sided material will use a standagrey diffuse VRayAdvanced material bydeault.

Additional control is provided by the ranlucency color setting . By deault it is setto 50% grey which would allow an equalamount o the ront and back to show (dep

dent upon illumination values).

o let more o the Back side material showthrough, push the color closer to white. retain more o the Front side material, briit closer to black.

You can also use color or a ranslucencytexture or experimenting with differenttranslucent effects.

In the example file scene 2_sided_spherelampyou’ll find the ollowing example figure 4.33

and other experiments rom my collection

figure 4.33

Note: In order or the Front side material to show all, it must be illuminated rom the ront. It’s a common mistake to light only rom the rear and expecthe ront side to show.



Page 50

In this short tutorial, I’ll guide you throughthe workflow needed to make the ake SSSeffect used on the Dragon figure 4.28 (on Page 48)

Open example file 2_sided_buddha.c4d

figure 4.34

Te scene figure 4.34 has a the Buddha figureand three primitive objects tucked neatly

inside his body. Create a VRayAdvanced material and adda Luminosity layer. Apply a blue Luminos-ity color, leave at 100% or brightness andadd a value o 10 in the second box labeledAmount

In Luminosity Layer parameters checkCompensate exposure.

Note: We’ll be covering Luminosity on the next page.

figure 4.35

Name this material ‘backlight’ and apply it tothe Null object called ‘Internal’ -We now have an internal lighting solutionor the Buddha figure.

Create a new VRayAdvanced material andname it ‘Outside’ In Diffuse Layer 1 check Use VRayDirt

Add dark blue or the Occluded color via color channel. (See page 43 or help)

Add a light blue or the Unoccluded colora color channel. (See page 43 or help)

Finally add Specular layer 1 and make no ditional changes.

Next, create a VRay2Sided material and athe material called ‘Outside’ to the ront simaterial option o the VRay2Sided materfigure 4.36

Finally apply the VRay2Sided material to the ‘Buddha’ figure and Render. figure 4.3

Tis backlit ake SSS effect has countless uand o course, it looks kinda cool!

figure 4.36

figure 4.37



Page 51

VRayBlendMaterial

Te VRayBlendMaterial allows you to stack materials - It works in almost exactly the same way as manally stacking them in the object manager, but allows or better management in some cases.

Te process starts off with a base layer such a brick map or example, then additional materials are ap-plied as a coat material, this could be useul or peeling paint o a layer o broken concrete.

Various mapping techniques that have some Material weight (alpha) or Diffuse Layer transparency areuseul in determining to what degree the underlying material is seen.

Below are some examples o materials that have been layered with this technique.

In figure 4.38 an underlying rock material is coated with a slightly translucent coating o snow.

In figure 4.39 glass is affected by a fiery layer and covered with a dusting o sand.

In figure 4.28 an organic rock is coated with a glow based effect based off a vertex map selection.

All very straight orward, but with amazing amounts o potential.


Layering shader - Standalone

Note: Tese files are all available in the VrayBlendMaterial older.



Page 52

VRayDisplaceMaterial

Te VRayDisplaceMaterial allows the usage o Displacement maps in VRay.

It’s possible to mix this material with a standard VRayAdvancedMaterial by stacking it to the right o tstandard material and choosing ‘Mix textures’ rom the texture tag. Let’s quickly explore.

Te ollowing example uses the Displacement type: 3D Mapping, which is suited to procedural effects.

Open example file displacement_user.c4d

figure 4.38

Create a standard VRayAdvanced material and apply it to the cube.

Create a VRayDisplaceMaterial and alsoapply to the cube object (afer the first mate-

rial)

Select the VRayDisplaceMaterial tag romthe object manager and check Mix exturesfigure 4.39

figure 4.39

In the VRayDisplaceMaterial’s texture patadd a noise channel rom the drop downmenu. Click the noise channel and changthe type to ‘Cel noise’, finally increase theGlobal scale value to 250%.

In the VRayDisplaceMaterial’s parameter

change the amount to 10cm and check thebox Keep contunity. Render. figure 4.40

figure 4.40

In figure 4.41 I’ve copied the ‘Cel noise’ to thVRayAdvancedMaterial’s diffuse channel,created a couple o layers with some noise variation and have used VRayDirt (page 43

See file displacement_example .c4d

figure 4.40

Use Cubic projection (or both)

Check Mix textures

Select VrayDisplacement material.



Page 53

Te Displacement type: 2D Mapping, is used when an image based displacement map is available.

With this workflow, you can maintain a low polygon count and depend on the displacement map to githe appearance o millions o polygons at a sub polygon level.

In examples figure 4.31 - figure 4.32 the renderedresults shows that although the originalmodel only had 68,000 polygons, they’vebeen effectively turned to 3.4 million poly-gons with a displacement map.

figure 4.31 ‘Octopus’

Parameters.Te amount value (in both the 3D and 2D option

control the maximum height o the displament map.

Te shif value specifies a constant amounthat the polygons will be shifed relative totheir normal position.

While Use deault parameters is checked, resolution or 3D displacement is controll via the VRayBridge settings under Displament.

Te deault amount can be set too high ocertain tasks and should be experimentedwith or optimal results.

For more in depth eatures relating to you

displacement needs, please reer to the VRmanual.

Note: It’s still possible to add a VRayDisplament ag rom the object manager, althougthis is the old workflow and only remainsavailable or Legacy reasons (to support old

files).

figure 4.42 (zoomed in)

figure 4.43 (zoomed in)

figure 4.33 -is the 16 bit ti image used to createthe displacement.



Page 54

Luminosity Layer‘VrayAdvancedMaterial’

Te Luminosity layer (rom the standard VRayAdvancedMaterial) provides light via sel illumination.

You can use sel-illuminated materials on objects to represent lights that don’t need an actual light souAn example would be the LCD display on the ront o a DVD player, or the backlight or a PDA device

In VRay, the Luminosity layer also has an option to turn the effect rom a standard sel illuminated marial into a ull fledged light source via the Direct Illumination option. Let’s take a look.

Open example file sel_illumination.c4d

Te render figure 4.44 has 2 sel illuminatedobjects and a white Environment light.

Using the luminosity layer in this mannerdoes not provide adequate shadow density tobe considered a viable lighting solution.

figure 4.44 (8 second render)

I you add a Physical Camera tag to the avail-able camera, there’s a drastic dip in exposure.figure 4.45

figure 4.45

o make the luminosity brightness adaptto the physical values o the camera checkCompensate exposure. figure 4.46

Note: Tis is easier than guessing a new intensityamount each time we make a change in exposure vi

the Physical camera parameters.

figure 4.46

Check the box Direct Illumination.

Tis turns the material rom a sel illumi-

nated source to a physical light source.

Enter an Intensity value o 200 or Direct lumination parameters.

Also in the Environment tag rom the Vrabridge settings, increase the Background E vironment brightness to 50 to compensat

figure 4.47 (Zoomed in)



Page 55

An increase in Subdivision amount rom theDirect illumination parameters can eliminateany unwanted noise. Tis process is sending

samples to the DMC sampler as discussed onpage 32.

Te Direct illumination method is sendingout light rom all o its surace normals andcan be quite slow to compute, however tospeed things up it’s possible to check Storewith irradiance map and have the lightsource compute during the IR Map cacheprocess.

Using this approach requires a slightly longerwaiting time during IR map creation, butshorter overall render time. It also comes at acost o a slightly decreased shadow density.

When the Direct illumination option ischecked the material now eatures light-ing properties almost identical to those o aVRay Area light.

Te Luminosity color channel and texturemap slots remain effective or colorization o

the light source, but the other channels sucha diffuse and specular would be no longeravailable.

Te result o the render should now look likeit does in figure 4.48



Direct illumination does not work with se

tion tags, instead the system will manuallyoverride and use standard sel illuminatioproperties.

In the case o a single object with geometryou wish to use or light (i.e a lamp and bulb

one object), it is necessary to double click thselection tag (or manually select the polygons) aseparate the geometry via the split com-mand. Cinema 4D lacks a split and delete

unction, so you would also be required toremove the remaining geometry rom theoriginal object.

Tis Direct illumination method can behighly beneficial to your workflow, but itis my recommendation to use it sparinglyand only in situations where a physical ligsource cannot accomplish the same task.

In figure 4.49 the IR Map was responsibleor the light source. A ull render reveals aslightly sofer result when compared to thmore grainy direct sampling method.



Page 56

Chapter 5: Vray lightsVRay lights are dependant on scale, when designing a shot with realism in mind it’s important to respthe process and work roughly at the real world size o the object in question. Does this always involvegetting out a calculator and pre-planning? No, but the closer you are, the more likely your lights are tobehave as expected.

Vray lights also have physical parameters or accurate measurement o light.

Lighting actual scenes isn’t a topic we’ll be discussing at length in this short book, but we’ll cover the bsics and get you up and running with a ew small example scenes.

A standard C4D light with shadow param-eters enabled will provide VRay with enoughinormation to render with a with the stan-dard Omni light option.

Te result is an underwhelming effect that’stypical o Omni lights when compared to theshadow density o an Area light. figure 5.01

figure 5.01 (rom example file VrayStudioOmni.c4d )

Adding a VRayLight tag to the pair o lightsand turning the deault Omni light to Arealight, a ew tweaks later things are starting tolook up. figure 5.02

figure 5.02 (rom example file VrayStudioArea.c4d )



Accomplishing this wasn’t a simple case oturning on Area lights, i you note in figure

that the Deault (image) intensity had to bcranked all the way up to 200.

Te reason or this is because we’re still using Cinema 4D’s units, which really don’trepresent any real world values. Instead iwe switch the Intensity units to Radiance

(W/m/m/sr), we get a much more accuratrepresentation o their actual brightness. Ithis case, the area lights are 100 watts.

Note: Always remember to ‘ enable shadowswhen working with VRayLights. (Tis paramecan be ound in the VRay Light - Common tab.)



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In the VRay manual...

Quote rom “http://vrayc4d.com/manuals/vrayorc4d-manual/common-tab” - VrayC4D Group. All right reserved.(c) 2008-2010

“Radiant power (W) - total emitted visible light power mea-sured in watts. When using this setting, the intensity o thelight does not depend on its size. Keep in mind that this is

not the same as the electric power consumed by a light bulbor example. A typical 100W light bulb only emits between2 and 3 watts as visible light.

Radiance (W/m²/sr) - visible light surace power measuredin watts per square meter per steradian. When this setting isused, the intensity o the light depends on its size.”

....the units are explained in a common senseway.

In the previous scene, the illuminationstrength or the light is heavily compensatedby the exposure settings o physical camera.Without the physical camera in place, thescene would have been massively overbright.

In example file watt_the_hell.c4d I have a verysmall area light in close proximity to thesphere with the physical camera tag re-moved. I’ve done this to view the lights intheir ‘raw’ deault intensity state.

Tis small area light has a Radiance (W/m²/sr) value o 20 and a Radiant power (W) value o 5.97.

figure 5.05 (rom example file watt_the_hell.c4d )

Increasing the size o the light figure 5.06, thRadiance (W/m²/sr) value remains at 20but the Radiant power (W) value has nowincreased to 41.7

Notice also that with the size change coma dramatic shif in shadow density. Tis is

real world phenomenon o course and queasy to understand why this would happeLarger area lights typically require moresamples to render accurately.

figure 5.06 (rom example file watt_the_hell.c4d )

figure 5.07

figure 5.08

In figure 5.08 I’ve changed the Area type toSphere. We’ll want to scale this down to reresent a bulb.



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As I decrease the Spherical Area light radiusto approximately 5cm, you’ll notice thatthe editor view becomes distracting andoverbright. Tis is a common nuisance thatrequires only a simple logical understandingto remedy.

figure 5.09

figure 5.10

VRay lights don’t have alloff parametersas they do in Cinema 4D. Tey’re physi-cal based and won’t respond to alloff sizechange. So to remedy this overbright statesimply manually drag the larger sphereshandles and close them down to approxi-

mately the size o your light radius.

With this you’re controlling the alloff dis-tance and editor visibility/brightness o saidlight and not anything related to the actualrender.

You can manually do this in the standardC4D light setting by clicking the light andnot the VRayLight tag. figure 5.11

figure 5.11

figure 5.11 (rom example file a_bulb_o_sorts.c4d )

Another quick render figure 5.11, Radiance(W/m²/sr) value o 401 and a Radiant pow(W) value o 41 So you get the picture.

Personally I stick with the native Cinema

units or lighting, they don’t represent anything but I’m comortable with that work-flow. It’s not imperative to learn about watage and luminous power etc, unless you’rea position to light based on pre-existing dIt’s all about personal preerence.

figure 5.12 Is one better than the other?

Te choice to use Rectangular lights vsSpherical figure 5.12 one is a question o “whright or the job” - Tey have uniquely diff

ent ways o casting shadows/light and shorepresent the kind o light you’re lookingto cast into the scene. Tough I find thespherical light to be highly versatile in a loo cases, the rectangular shape is good orwhole range o lighting situations.



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Area Light - Light portalsWe’ve taken a quick look at Area light settings, now we’ll dig a little deeper

figure 5.13

In figure 5.13 we have a typical Sun/Sky setupwith a very small opening. Tis is allowing alittle light to enter the room, but not enoughsamples are reaching the interior or a qual-ity result. Te first idea would be to totallymax out the IR map, DMC sampler settingsetc, but there’s a simpler way to approach thiswith a Light Portal.

Open scene Small_Hole.c4d and i you’d like torender to the picture render or comparison.

First thing to notice in the scene is an AreaLight that has been turned off. Opening the

light parameters via the Vray light tag revealswhat looks to be only a standard area light,however the property ‘Light portal’ has beenswitched rom Normal to Portal Light.

Checking the light to on in the OM and re-rendering will now show a much clearer andless splotchy render. figure 5.14

figure 5.14

Te light portal setting has effectively turnthis light source into a sort o directionalguide or the samples.

In my crap illustration below figure 5.15 youcan see that without the Light Portal, the rsamples miss the mark and don’t make it ithe scene. With the Light Portal activatedthe samples have assistance in their intenddirection .

figure 5.15

Te other solution is the Simple Light Porwhich ignores any lights/objects behind thportal and takes only the environment cointo consideration. Tis can speed up the

workflow slightly. Light Portals can be helpul but are rarelyused in latest versions o Vray as the GI alrithm has become more refined. Tough isituations like this, they can be used to yoadvantage.



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Area Light - DomeTe Area light type - Dome is a similar to using a color or hdr effect as the Environment backgroundcolor, but uses direct sampling to provide a much more accurate result.

figure 5.16 (Environment rom VRay Settings)

figure 5.17 (Environment slot VRay Settings)

In figures 5.16 & 5.17 I’ve loaded a *.hdr imageinto the texture slot o the Environmentbackground and have a standard GI setupready to render.

Te resulting render figure 5.18 has beenprocessed much like a standard luminancematerial. Light is being cast into the scenebut the sampling method is not direct.

While this is suitable or most tasks (espe-cially with an accompanying light setup), iyou want some extra bang or your buck, theArea light Dome is more powerul.

figure 5.18

figure 5.19

figure 5.16 (Environment tab rom VRay Settings)

figure 5.20

Controlling this light source is straight oward. Position o the light in your scene isirrelevant, however rotation values will affthe orientation o an image based map.

A color/texture/material effect is loaded inthe slot (in this case ennis.hdr) and the result fig

5.20 is a directly sampled dome light.

Samples can be adjusted according.





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Area Light - Remaining settingsWe’ll take a brie at the remaining settings rom the Area light tab.

Affect Reflections: With this option unchecked, the brightness o the light will be ignored by the materreflectivity.

Invisible: All light sources are visible unless otherwise indicated. Unchecking this option will provide alight source, thought the origin o the light will not be visible.

No Decay: All lights in VRay have decay (alloff) based on real world calculations. Enabling No Decaywill essentially create a light source with no alloff at all. Tis is not recommended when trying to realically light a scene, but can be useul in product shots i you require an infinite light source.

Double sided: A rectangular area light emits light rom the Z+ direction only, enabling Double Sidedenables the light to illuminate rom both surace normals. *CHECK

Samples: As discussed on Page 32, the amount o samples used determines the quality o the light sourLights producing undesirable noise benefit rom additional samples.

Store with Irradiance map Using this option, the light calculated rom the Area map is processed andstored during the Irradiance map calculation. Discussed on Page 55.



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IES lightsIES data is taken rom existing real world lighting fixtures and is made available or users in varyingproessions to download and utilize in their projects.

figure 5.25

An IES represents the shape o the lights all-off, but not the alloff amount. In figure 5.25 it’s

easy to recognize the differences in how eachlight reacts to the IES data.

Open example file IES_scene.c4d

Te first thing you’ll notice in this scene iusing Cinema 4D version 12 or higher, isthat the visual reerence o the IES light isincorrectly oriented figure 5.26.

figure 5.26

Tis is the standard rotational value o thedeault light. o fix it, rotate the p axis (the blue

handle) to -90°. Note: argets will always utilizethe P axis.

Omni is the light type indicated to use whworking with IES files. Creating a standar

light and enabling shadows, you can thenquickly move over the IES tab and load yodesired IES file.Open example file IES_scene2.c4d

figure 5.27

In this scene figure 5.27 the light is unchangand retains the deault brightness as con-tained in the IES data. o increase brightnyou can enter a Lumens value or an increin intensity, this value would typically bequite high. I’m going to increase to 10,000 Enabling Sof shadows does as you would pect, it sofens the shadow density, which occasionally desirable and only slightly mtime consuming to render.

A hint o color in the filter color will tintthe IES light to the desired value. Rarely alights 100% white, making a tint a worth-while change. figure 5.28

figure 5.28



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Final notes on lightingTe remaining light sources are Spot, Infinite and Parallel. I won’t cover these in detail because their prameters are logical and require no special attention.

In uture PDF instructional manuals we’ll take a closer look at lighting individual scenes.

Lighting in VRay is a unique process, one that can be as simple as the Physical Sun/Sky setup or as complex as lighting a city. My advice is to stay away rom the simplest work flow and push the boundaries what can be done with lighting and composition.

Beore tackling a project that involves a lighting rig, try to think o the balance you want to strike beohand. In a night time shot or example - Would it be wise to create the overall environment light first, filetc and then work your way down to the lighting fixtures? I would say not. My approach is to always stasmall, lighting fixtures first, achieve a sense o balance with the smaller details and when you’ve refined

and refined some more, only then would it be time to look towards the bigger lights.

Lighting can be a tedious part o the process i you make it so, continuously rendering the same shot tiand time again. Tis is why I recommend a base test setting, where the results o your scene lights canbe visualized in a matter o seconds vs waiting 10 minutes every time you make a change. Get used toswitching out between crap settings and medium ones to ensure you get overall sense or your scene anto ensure that with better settings, the lights will withstand scrutiny.

When you arrive to a point where the correct values flow, lighting is perhaps the most interesting parto the project, afer all this process is what brings your work to lie. It makes or breaks your work, so p

careul attention to what the masters do and try to replicate the best rigs without settling or mediocrit



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Chapter 6: Environment FogPrior to there being a working og solution in VRay, there were definite limitations when using the renengine or environment design and landscapes. Eventually ChaosGroup introduced the Environment which is a unique and physically accurate calculation o scene og. Te concept may seem quite limitin“how ofen do I want og?” Yet the implementation opens up a world o creativity.

Let’s first take a quick look at what it can do in terms o finished projects.

figure 6.1 ‘Sunday’ figure 6.2 ‘Fall’ figure 6.3 Modern og test

Te scene ‘Sunday’ figure 6.1 is initially setup with only a physical sun/sky, but due to the Environment and the enabled Scatter GI parameter, the sun light is able to illuminate the og. Te result as in real lithat the og itsel becomes a source o illumination or the scene and the actual sun light and it’s potenshadow casting has diminished to such a degree that it’s almost completely invisible. An increase in ex

sure and an adequate interior lighting rig restores the balance.

Te scene ‘Fall’ figure 6.2 is setup with Proxy objects and consists o around 2 billion polygons. Fog withscattering is enabled and is indicated to reach a height o 4 meters at a distance o 50 meters. Tis clearthe way or sun to still have a visible affect on the scene, but creates a sense o depth that would otherwnot be possible.

Te scene ‘Modern og test’ figure 6.3 was the first real test where I used the Environment og parameterGiven my lack o understanding at the time it’s easy to or me to critique the work. Te og height is essentially infinite, which under such heavy og cover doesn’t allow any light penetration rom the Sun.

Given an opportunity to re-work this piece, I would have chosen more fitting parameters.

So let’s do that, let’s figure out what works best by creating a og lit scene.



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figure 6.4

Open example file Home_og.c4d

Here figure 6.4 we have another typical Sun/Sky setup, pretty standard scene. We’re goingto spice things up with a little og.

First, let’s go to the editor camera and createa primitive cube figure 6.5.

figure 6.5

Manipulate the cube to extend the outsideo the building, without penetrating the thewindow & building layer figure 6.6. We’re keep-ing the og strictly outside.

figure 6.5 - Cube has Xray effect or illustration only.

In the VRay settings rollout or Environmwe’re going to activate Environment Fog.

figure 6.6

I you’d like to run a test render, you’ll seeresults are almost completely black.

Add the Cube object to the open slot orGizmos and add the Sun object to the opeslot or Lights.

Another render reveals a shot almost idencal to the original, minus the slightest hinhaze figure 6.7.

figure 6.7

We’ll want to check the Scatter GI box.

Tis tells VRay to look at the Fog as a vol-

ume and calculate its light solution based the density o that matter. Te scattering wboth illuminate the og and determine homuch light can escape the solution.

Another render would still resemble that the original.



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o finally see a result o using the Environ-ment Fog, we’ll want to manipulate the FogDistance parameter, bringing that numerical value down rom 1000 to around 100.

Te change in distance affects the density, visible og at closer proximity is now thicker,

allowing less light to penetrate.

Your result may look slightly different thanmine figure 6.8 based on the exact shape oyour Gizmo geometry.

figure 6.8

Te Gizmo object (setting geometry as the og) is the preerred workflow as this givesus more control over the density o the og.Without a gizmo we’re using infinite ogdepth and using the Fog height parameterwhich can be more difficult to control.

Sunlight is still able to penetrate the scene,but has become obscured by the og element.Subtle compensation with exposure or aninterior lighting rig would be the next step.

It’s possible to use any shapes as a Gizmoobject no matter how irregular, allowing youto experiment with just about any geometryimaginable.

It’s also possible to use as many light asrequired in order to scatter light through theog density.

In figure 6.9 I’ve added two makeshif securlights outside the building and includedthose additions in the Environment og Lislot.

figure 6.9

You can see that this simple addition hadadded to the og illumination, which in tucasts more unique light into the scene.

A couple o interior lights to compliment outside, a little urniture, materiality and yhave an interesting setup. Certainly something outside o the boring Physical sky lo

figure 6.10

By adding some outside eatures, you’ll givlie and more depth to the exterior. In figur

6.11 the eye is drawn to the passers by, whicreates more interest.

figure 6.11



Page 68

LinksI’d have spent some time teaching VRay or animation, but upon review there is little more I can say thwhat has already been clearly spelled out on the VRay message board by ‘SRA’

Tese step by step guides will get you through both ‘GI object animation’ and ‘GI camera animation’Tough i you have any remaining questions, please eel ree to email me @ [email protected]

http://orum.vrayorc4d.com/showthread.php?t=7727&highlight=object+animationhttp://orum.vrayorc4d.com/showthread.php?t=7728

Even with knowledge o VRayForC4D, I still reer to these tutorials as a step by step checklist.

For Clarification and urther reading on any o the subjects covered here, the VRay manual is an excelresources with up to date inormation.

http://vrayc4d.com/manuals/booktree

Here’s a couple o older tutorials I created with regard to illuminating skyscrapersYou may or may not find these useul.

http://vrayc4d.com/manuals/vrayc4d-tutorials/skyscraper-lighting-inthecity http://vrayc4d.com/manuals/vrayc4d-tutorials/city-illumination-inthecity

For Free models

http://archive3d.net/

And the best collection o textures available online

http://www.cgtextures.com/

And finally - Exclusively VRay based materials

http://www.vrayorc4d.com/portal/materials/



Tat’s a wrapI hope your experiences with this booklet have been positive.

I you have any additional question or clarification please contact me at

[email protected]

Join me again in the near uture.

Documents

Introducing v Ray