Setting Up Render Layers/Passes

Maya, Mental Ray: Lighting

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RENDER LAYERS AND PASSES

There’s two main ways to break up images in Maya.

1. Render Layers
2. Render Passes

Render Layers give us full manual control, and layers are created by the user. I use these a lot to get exactly the result I’m after as they give us full manual control and there are some presets too. Render layers work with MR and Maya software renders. Each image will be rendered separately giving longer render times. Usually there’s a folder created and named for each pass and individual image sequences in each folder.

Render Passes are a Mental Ray feature and offer many built in presets. They’re convenient as they’re fast to render since the image only has to be calculated once and split into passes after. We can also create custom setups by using MR nodes in the hypershade, particularly useful for SSS layers. Render Passes are usually rendered inside of a single .EXR image file like layers in Photoshop and then broken apart by the compositing program.

 

RENDER LAYERS

Render Layers, not to be confused with render layers are in the tab next to our regular “layers” window at the bottom right of the screen. Here we can add “render layers” so that when we batch render, Maya can render out multiple versions of the same frames for compositing.

Render Layers must re render the whole image so they will take extra time to render unlike “Render Passes” which are setup for Mental Ray. (see below)

At render time files will be rendered into the images folder under the layer name.

Render passes can also be used to assign real time shaders for animators without destroying the renderable shaders.

Main Points
1. Right click “copy layer” this will create a new layer identical to the current
2. Shaders are automatically assigned only on the current layer. Other layers will retain old assigned shaders.
3. Visibility of objects and lights only affects current layer
(Sometimes can be buggy, to manually set create a layer override for visability of an object.)
4. Layer Overrides are the way we can assign a value of any attribute to the current layer. Right click on any attribute in the attribute editor. Good for switch Final Gather on and off per layer.
5. A batch render will render all layers with the green tick on them in individual folders called the layer name. To disable layers click on the green tick icon and it will turn into a red cross.

1. Maya Render Layers Introduction
1min 20sec

YouTube / andrew silke - via Iframely

To see how to setup After Effects for some of these passes go here.

2. Render Layers: Creating A Foreground and Background With Visibility
2min 43sec

YouTube / andrew silke - via Iframely

3. Render Layers: Assigning Shaders and Ambient Occlusion
5min 58sec

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4. Render Layers: Layer Overides and Separating Specular
4min 53sec

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5. Render Layers: Layer Overides Final Gather
1min 02sec

YouTube / andrew silke - via Iframely

6. Render Layers: Use Background for Catching Shadows
4min 18sec

YouTube / andrew silke - via Iframely

7. Render Layers: RGB Mattes for Compositing Separate Objects
3min 40sec

YouTube / andrew silke - via Iframely

8. Render Layers: Creating A Depth Map for Depth Of Field Blur
4min 58sec

YouTube / andrew silke - via Iframely

9. Render Layers: Batch Render Settings and Compositing Example
7min 33sec

YouTube / andrew silke - via Iframely

To see how to setup After Effects for some of these passes go here.

MR RENDER PASSES

Render Passes unlike Render Layers don’t take any extra time to render. They’re built into Mental Ray and we can create our own via “custom passes” nodes

The resulting images are broken into layers or separate files for things like AO, diffuse, specular reflection and shadows whilst still rendering out the combined or “beauty” pass. All things we can tweak in comp later weather it After Effects or Nuke or your compositing program.

Render Passes aren’t supported by all shaders, so test out some images to see what works first.

Passes Tab
The passes tab is found in the Render Settings window under Mental Ray under “Passes” This is where we can manage our passes.

The description of each pass can be found in the Mental Ray Docs

Creating Passes
Click on the “Create Render Passes” button, select the passe or multiple passes and then click create.

The passes haven’t been created just yet, they’re waiting in the “Scene Passes” window. To assign them we must associate them to our scene.

Make sure we’re in the current Render Layer” because the passes will be associated with that layer.

Click “Associate Selected Passes”

You can move passes in and out of the Associated Passes window. These will be the ones rendered when we batch render.

If you click on AO make sure the feature is enabled
Indirect Lighting > tick Ambient Occlusion

Render the image. Once finished you can view your render pass by going

File > Load Render Pass > (click the pass you wish to view)

Files can be found in the project under images directory then “temp”

We can change what the files are called by changing
render settings > Common > filename prefix
to…

characterTest

.exr as a file format gives us further naming options.

Render Sets
We can group render passes into sets. We only need to add a single set. and manage these sets under

Use the relationship editor to link/manage render passes after they’ve been created.

Window > Relationship Editors > Render Pass Sets

Render Passes and Layers (Andrew Klien)

YouTube / Andrew Klein - via Iframely

Maya render passes Part 1 – Tutorial

YouTube / Ashraf Aiad - via Iframely

Maya render passes Part 2 – Tutorial

YouTube / Ashraf Aiad - via Iframely

Instructor

Andrew Silke

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