3DS MAX:LIGHTINGANALYSIS

WASSIM JABI AND SERGIO PINEDA

WELSH SCHOOL OF ARCHITECTURE - CARDIFF UNIVERSITY

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The objective of this tutorial is to represent and evaluate daylight conditions in interior spaces. For this we will create a “room” with a window. The rendering and analysis steps could be applied to any other 3d model of a house, or other type of building. To create the room, make sure that the dimensions of your file are set to Metres (metric system) create a box by clicking on create (1), geom-etry(2) and box(3). We will create a room of 5m by 7m by 4m (4).

We will create a smaller box for the interior space of the room. Clone the existing box (select the first box, press ctrl v and click on copy), go to modify (1), and change the dimensions of the box (2). We will give 0.30m walls to the room, so the interior dimensions are 4.4m, 6.4m and 3.4m.

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To make sure that the boxes are aligned, click on align (1), and center them on x, y and z (2).

We are going to substract now the interior box from the external one by Performing a Boolean operation: after selecting the ex-ternal box click on create (1), select compound objects (2), and choose Boolean (3). Make sure the options are set to “Substraction (A-B)”and click on “Pick operand b” (3). Finally click on the interior box.

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We are now going to incorporate a window, by creating a box of 3m by 2m (and a depth bigger that the thickness of the wall in order to substract it). As with the box for the interior of the room, you can change the dimensions of the box by clicking on Modify (1) and inserting new dimensions (2).

Now locate the window where you want it to be. An easy way of doing this is to center the window in relation to the room and then move it to the desired location. A second option is to locate the room at [0,0,0] by selecting it, right-clicking the move icon and changing all values to 0. Then select the box made for the window, right click on the move icon again (1), and insert 0 for x, -2.5 for y and 1.2 for z (2).

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To substract the window volume from the room walls, perform a Boolean operation: after selecting room click on create (1), select compound objects (2), and choose Boolean (3). Make sure the options are set to “Substraction (A-B)”and click on “Pick operand b” (3). Finally click on the box made for the window.

At this point you have now modeled the walls of a room with a window, the floor and the ceiling. Well done :)

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We are now going to make one of the walls of the room a separate entity in order to be able to hide it when needed. For this, cre-ate a box overlaping the wall opposite to the window. Give this wall dimensions of 0.4m, 10m, and 10m (1).

Making sure you’ve selected this new box, right click on the move icon (1) and insert the following values (2): 0 for x, 2.4 for y and 0 for z. This will align it with the interior border of the wall we wish to replace.

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Perform another booleans substraction (as in page 5) so that the room now has one open side. Then create a new box.

Give the new box the following dimensions: 0.3m, 7.0m and 4.0m (1).

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Select the new wall, right click on the move icon (1), and insert the following values: 0 for x, 2.35 for y and 0 for z. This will locate the wall precisely in such a way that the room is once again closed.

Now select everything in the scene and click on the Materials Editor (1). Select the the first material on the upper left-hand corner (2) and select a new template (3). Set the template to Matte Finish. Finally, apply the new material to all the objects in the scene (4).

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Now select everything in the scene, right click on it, and convert it to editable mesh (1). This will enable us to select the interior surfaces of the room individually and assign different materials to the roof and the walls.

Select only the wall that was modeled separately, right click on it and hide it (1).

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Click on modify (1) and then on ‘select by polygon’ (2). Select now the floor of the room.

Click on the Materials Editor (1). Select the the second material (2) and click where it says Arch & Design (3). We are going to gain access different libraries of materials for the floor, the walls, and the glazing.

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Click on Material library (1) and Merge (2). This will enable us to merge a series of material libraries together. In the window that opens, go to: C:\Program Files\Autodesk\3ds Max Design 2010\materiallibraries

Choose ‘Autodesk.Max.ProMaterials.Hardwood’ (1).

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In the new window that appears, click on All (1) and OK (2). Repeat the process for the following material libraries: ProMaterials Wall Paint, ProMaterials Masonry/CMU, and ProMaterials Glazing.

You now have many options to choose from for floors, walls and windows. Start by choosing Hardwood Flooring Chestnut Natural (1) by double clicking on it.

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Now apply it onto the floor (1).

Do a test render by clicking on the rendering menu (1), selecting a size of 320X240 (2), and clicking on Render (3). At this point you should be getting a floor tiling pattern!

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Follow the same process with the walls. You can experiment with different materials. For example, some of the materials you may want to apply are: ‘CMU Light Gray Running’ from the ProMaterials Masonry/CMU library, or ‘Paint Antique White Flat’ from the ProMaterials Paint library.

Now we are going to create a glass panel for the window. Start by creating a box with the following dimensions: 0.01m, 3.0m, and 2.0m (1). Locate it at 0.0 in x, -2.45 in y and 1.2 in z (2). Remember you can insert these values by right clicking on the move icon.

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Apply on the glass panel the ‘glazing clear’ material from the ProMaterials Glazing Library just as you created and selected materials for the floor and the walls.

We’ve now applied all the interior materials need, and will proceed to create daylight conditions. Click on create (1), Systems (2), and Daylight (3).

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In the plan view, locate the daylight compass near the [0,0] of the drawing, expand the directional symbol, and locate the daylight indicator at a medium distance from the room (1) making sure you say ‘yes’ when prompted if you wish a ‘Physical sky’. Choose time (2), date (3), location (4) and make sure that the orbital scale is around 30m (5).

By right clicking, unhide all (1).

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We will now introduce a Sky Portal - an object that provides an efficient method of ‘gathering’ existing sky lighting in interior scenes without requiring high final gather or global illumination settings that would result in excessively long render times. In effect, the sky portal acts as an area light that derives its brightness and colouring from the environment. To begin, make sure mental ray is the active production renderer. Click on the render setup icon (1), then on ‘Assign Renderer’ (2), and make sure that it says ‘Mental Ray Ren-derer’ next to ‘Production’ (1).

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Make sure that in the settings for your daylight system you’ve selected mr Sun (for Sunlight object) and mr Sky (for Skylight object). For this, select your daylight system icon (1), then go to the modify menu (2) and click on the Sunlight and Skylight drop down menus to select mr Sun and mr Sky (3 & 4).

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Now, add a mr Skylight Portal object by clicking on Create (1), lights (2), and mr Skylight Portal (3). The portal is a wireframe rectan-gle with a central/perpendicular arrow showing in the direction of light flow. For best results make the portal slightly larger than the window opening and position it immediately outside the opening. For the case of our window, we will be drawing the portal in the ‘Front’ view, and will give the portal dimensions of 2.1 in length and 3.1 in width (3).

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To locate the Sky Portal directly outside of the window opening, select the portal (1) and then right click on the move command (2). Insert the following values: x = 0.0, y = -2.5, z = 2.2 (3). This will locate the sky portal exactly outside of the window opening.

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Make sure the portal’s arrow is pointing towards the interior of the room (1). If this is not the case, toggle it’s Flip Light Flux Direction check box on the sky portal parameters rollout (2).

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To make sure that the sky portal works appropriately, turn on the ‘Final Gather’ in the rendering setup of the scene. For this, click on the Render Setup icon (1), then select the Indirect Illumination menu (2), and make sure that the ‘Enable Final Gather’ option is ticked (3). This means that at the time of rendering the sky portal will be taken into account.

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Create a camera inside the room. For this, click on create (1), camera (2), target (3), and place it in the plan drawing in a corner look-ing towards the window. By adjusting the location of the camera, the target view, and the amplitude of the lense, set a view.

Do a basic rendering (as in page 13 of this tutorial). The light is surely quite dark. This is because the default settings for the exposure in 3dStudioMax are set for external locations. We’re now going to change these settings.

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Go to Rendering and Exposure Control (1).

First click on ‘Render Preview’ (1). Now choose the preset ‘Physically based lighting, Indoor Daylight’ (2) in the exposure presets. Click on render preview again. You’ll notice a difference. Make sure the Exposure value is around 9 or 10 (3).

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Click on the Rendered Frame Window (1) and change the value of the ‘FG Bounces’ to 6 (2). This will change the amount of times the bounces of light are calculated in the image. Anything between 4 and 7 is optimal. Beyond 7 it requires increasingly longer times to render. Render again to see the changes.

Now select the wall that is modeled separately and go to Edit menu and Object Properties (1).

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In the tab for ‘General’ click on By Layer so it becomes By Object (1); change ‘Visible to Camera’ so that it is unticked (2), and click OK (3).

Set the perspective view outside of the box and render again. The wall now is invisible to the camera, but it still keeps the daylight out of the room. We can now make renderings of the interior of the room with a camera that is on the exterior, without compromising the accuracy of the daylight representation.

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Save the file at this point, as this will be your accurate rendering file for a visual representation of daylight in the room. Save a copy of the file under a different name. We are now going to work on this copy of the file to produce a daylight analysis of the values of daylight coming into the room. Start by clicking on the Lighting Analysis menu and Lighting Analysis Assistant (1).

Making sure you are in the plan view, go to the Analysis Output menu (1) and create a light meter (2).

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Making sure your snaps are on (1), insert points for a rectangle equivalent to the interior area of the room. This is going to be the Light Meter rectangle.

You can modify the dimensions for the Light Meter rectangle in the modify menu (1). You can also change the segments, to obtain as many values as you wish (2). Insert 8 by 12 segments, in such a way that you now have 96 values in the overall calculation of the day-light of the room (each one of the arrows in the perspective view represents a value). Also make sure the z value of the Light Meter is just above the floor level (3). Some centimeters above the floor level should do.

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Select the daylight system, and click on Modify (1). Change it’s Sky Parameters to C.I.E. Make sure ithe option ‘Overcast Sky’ (2) is selected and bring down the Direct Normal Illuminance to zero (3). At the bottom of the modify menu click on ‘Calculate All Light Meters’.

The image you get at this point shows values for daylight at the specific locations of the Daylight Meter. The colours though may all be in the range of blues and greens only. To expand the range of tones of the graph, open again the Lighting Analysis Assistant under the Lighting Analysis menu (1). Click on General (2). Modify the value in the ‘Max’ window (3) to match the highest value in your room.

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In relation to the values of the scene below, we have changed the ‘Max’ value to 1050. This brings out all the tones in the graph. Modify the Max value until you find the one that best suits the specific daylight conditions your are evaluating.

Close the Lighting Analysis Assistant window, and scroll down the Modify window for the Light Meter. You will find the options for the ‘Values to Display’ (1), which enables you to evaluate different kinds of values for daylight within the interior of your room. Choose Total Illuminance, and press the screenshot key on your keyboar (Prt Scr) which is next to the F12 key in Windows machines. Go to Photoshop, create a new file, and paste your screen shot. This is your visual documentation for the Daylight values. Back in 3dStudio-Max, click on the ‘Export CSV File’ option (2). Save the CSV file when prompted, and open it in Excel.

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The CSV file in Excel gives you the precise numerical values of your daylight analysis.

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To avoid white borders (and unreal figures) around the perimeter of your colour graph reduce the light meter in size, so that it sits some 20 cm away from the walls. Congratulations! You can now create accurate daylight representations of interior spaces as render-ings and evaluate daylight conditions with precision in the form of colour coded spatial representations and spreadsheets of values.

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ADDITIONAL INFORMATION AND RESOURCES

1. Learning More about daylighting analysis in 3D Studio MAX:

Getting Started: http://images.autodesk.com/adsk/files/3dsmax_started.pdfAdvanced: http://images.autodesk.com/adsk/files/3dsmax_advanced.pdf

2. Moving data from Revit to 3D Studio MAXhttp://images.autodesk.com/adsk/files/revit_to_max_whitepaper__2sept2008.pdfhttp://images.autodesk.com/adsk/files/revit2max-9_whitepaper_.mb.4-21-08.v1.pdf

3. Cardiff-specific weather data file:

Rather than use a generic description of sky conditions (e.g. overcast or clear), 3DS MAX can load a weather data file that con-tains accurate measurements of sky conditions and other weather data for specific dates and times. This file has the extension .epw (acronym for EnergyPlus Weather data file). EnergyPlus is the most popular energy analysis software from the Department of Energy (DOE) in the United States. Weather data files are available for many cities at the following website:

http://apps1.eere.energy.gov/buildings/energyplus/cfm/weather_data.cfm

Cardiff is not included. However, WSA has the Cardiff .epw file available at the S: drive at:

S:\TEACHING\BSc 2nd year\2nd Year 09-10\Tutorials\3DSM\3DSM_LIGHTINGANALYSIS

Instructions on how to load and use a .epw file is available in the Help section of 3D Studio MAX (search for “weather data file”). A comprehensive tutorial on the use of daylighting and artificial lights in 3DS Max is available in the Tutorials section (POINT THEM to the Mediterranean Villa tutorial).

4. Specifying the Latitude and Longitude for CardiffCardiff is not included in the list of cities in 3D Studio MAX. You can however, enter the latitude and longitude manually.

Cardiff ’s Latitude is 51°29’N and its Longitude is 03°10’W

5. Artificial Photometric Lights

Some students may wish to add artificial photometric lights. As mentioned in the lecture, the ERCO website includes both 3D models of the luminaires and the IES data for them. Information on how to load the IES files is available in the Help section of the software (Search for “Photometric lights”)

3DS MAX models and IES data of luminaires can be downloaded from:http://www.erco.com

Click on “Download”Scroll to Bottom of web page for “Design Data: luminaires”

6. Real-time interactive Pseudo-color Exposure Control:3D Studio MAX allows you to quickly study the effects of your lighting by displaying in the viewport pseudo-colors of luminance data. See the following YouTube video on how to accomplish this:http://www.youtube.com/watch?v=n96U9ifyQbU&feature=related

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