2016 | Intro to 3D | Week 06 | Rendering Me Again!€¦ · Maya Hardware Peter Chapman | Bradford University • Uses your graphics card’s processor to render (but not the same

Me Again!

Peter Chapman | Bradford University

Peter Chapman

[email protected]@gmail.com – if it’s important / time-sensitive

Issues? Working on something specific? Need some direction?

Don’t hesitate to get in touch

http://peter-chapman.co.uk/teaching

2016 | Intro to 3D | Week 06 | Rendering

mailto:[email protected]

mailto:[email protected]

Rendering theory & practice


• This can be the most time consuming part of the process depending on the complexity of your scene

• Many people underestimate the time needed

• Can easily be a massive time-drain!


Introduction


• Scene complete = time to start rendering!• How do you want to render it?• Should think about rendering all the way through your

production –don’t leave it till the end!• Create models and textures with the final image in

mind• Gear lighting towards showing off the scene

• Which renderer?• Maya software, Maya hardware, Mental Ray, Maya

vector, Vray, Octane


Different Renderers


• Each engine renders differently and can give entirely different results

• Choice depends on:• the final look you want• number of machines you have• Number of licenses you have• Time / Budget

• It’s best to choice the render engine before you begin creating your scene and essential before lighting and shading.


Some Basics


• Choose an appropriate resolution and aspect ratio – where will the final output be displayed?

• ALWAYS Render to frame files rather than movie files• Open iff from maya, or png / tiff but never jpeg!

• Use file formats that use no compression or loss-less compression

• Use anti-aliasing (within reason)• Use Ray tracing wisely (expensive)• Don’t just ramp everything to max! Be smart!


Which is best and why?


• discuss


Maya Software


• Default software rending solution• Can capture just about anything you want in your scene

• Reflections, Motion Blur, Transparencies• Good one to start with• Render quality depends on anti-aliasing and ray-tracing• Often under-estimated• Can be fantastic when combined with an occlusion pass


Maya Hardware


• Uses your graphics card’s processor to render (but not the same as GPU renderers such as Octane)

• Similar to what you will see when you play a 3D video game

• Data output by the game is fed directly into the graphics pipeline and rendered on the fly as you play.

• Results in faster render times, but lacks some of the features and quality you get from software render

• Don’t use it


Mental Ray


• Now included and heavily integrated into Maya• True Physical render engine allows amazing realism• Emulate the behaviour of light more realistically• Can be an advanced renderer with shaders and procedures

of it’s own• Can be used to generate occlusion passes


GPU Renderers (Octane / Vray)


• Use advanced GPU’s (usually Nvidea CUDA cores) to render very quickly and realistically using the architecture of a GPU – hundreds (or thousands) of cores doing simple things rather than a few powerful cores such as a CPU

• Requires using it’s own shaders / cameras etc


Global Illumination


• This simulates the interaction of light with the entireenvironment rather than individual surfaces

• Light is tracked from emitters to sensors• Shadows are automatically generated, as are interactions

between surfaces• There are two common approaches: ray tracing and

radiosity• Before we look at these in detail, we should look at some

general features of global illumination


Global Illumination


• Ignoring the fact that the calculations (as we shall see later) are complex, the solution to global illumination is simple:

• Start at a light source• Trace every light path through the environment until it

either:• Hits the eye point• Has its energy reduced below a threshold• Travels out of the environment


Surface to Surface


• We can also model the way one surface interacts with another

• This is easier to consider non-mathematically• Four different interactions:

• diffuse to diffuse• specular to diffuse• diffuse to specular• specular to specular

• Colour bleed, colour in shadows, etc


Raytracing



A Classic Ray-Traced Scene







Simple Rendering Best Practice


• Model & Texture appropriately• Level of detail needed not over done• Close objects high detail…objects further way less

• Use line render, play blasts, test renders• Avoid mistakes re-rendering costly

• Only use features necessary• Paint effects, final gather etc all take time

• Split your scene up• Multi-pass / Batch rendering / Network Rendering /

Distributed Rendering where appropriate


Questions?


Course | Industry | Me | Anything!


Documents

2016 | Intro to 3D | Week 06 | Rendering Me Again!€¦ · Maya Hardware Peter Chapman | Bradford University • Uses your graphics card’s processor to render (but not the same