Join Lee Lanier for an in-depth discussion in this video Creating render passes using mental ray, part of Maya: Rendering for After Effects Composites (2012).
So far we have set up render passes through the Render layer Editor. Now we are going to move on and use a mental ray Contribution Map System to set up render passes. This is a more advanced method, and it will give us more control. So back to project 1. This version of the file, which is shot one step three only has a master layer, which is fine. We don't need any other custom layers through the layer editor at this point. What we can do is go straight to mental ray and set it up through the mental ray settings in the render settings window. Before we do that though, there are a couple of good things to do just to make sure that when we do render, everything is going to be nice.
One is we need to hide the image plane. So this will show up in the Batch Renders, and that's not a good thing to have it in the background. So I am going to go into View > Image Plane > Image Plane Attributes. I am going to turn Alpha Gain back down to 0, and that hides it from that view. Now we can go into the render settings window, and if it's not already switched, switch to mental ray. Once on mental ray you have all the different mental ray tabs. Now since we are here let's check the quality. We are going to make sure we have high quality. So in order to change the Min Sample Level and Max Sample Level, we can change the Custom Sampling and switch from 0 to 2. Now low quality would be -2, 0.
High-quality will be 0, 2. So 0, 2 is good in this case. So now we can set up some passes. And this happens to the passes tabs in this window. Now initially there are no passes here, but you can create them through this Create render pass button, right here, and here is a long list of mental ray render passes. Now we don't need all of these, but there are actually five, in this case. So it will be good for this project where we need to integrate this spyglass with the footage of the actress. What we can do is click one of these--or select more than one by Ctrl-clicking, or Command-clicking, the names. So let's start picking a few.
The first one we want is called Diffuse Material Color. I am going to describe these in the second. Let's go further down. The next one we need is Matte. So I am going to Ctrl-click that. The next one after that is Reflection. Control click. The next one is something called Raw Shadow. Now it's easy to get these mixed up. There are multiple shadow variations, there's a shadow here. We actually want Raw Shadow. That will produce a slightly different result. So Raw Shadow, and then last one is Specular. Let's talk about what these are going to do.
Diffuse Material Color will render the diffuse color, but without shadows, and without shading. The next one Matte, we talked about this a little bit before, but a Matte will render a white and black version of the image you can use to cut out something in the composite. Raw Shadow will produce a shadow, and this will be a white and black render of the shadow just in the RGB. Reflection is just the reflective component, and Specular is a just a specular component. So we have these picked now. Let's go ahead and Create and Close, and they're listed in the scene passes section.
We can now pass these down to the next section, which is the Associated Passes section by using this Associate button. And those are brought down. At this point, if we go further down I can make a contribution map, and this is something necessary to associate the passes with the render, in that particular layer, which is the master layer. So to make a new contribution map, I can use this button right here. Now if I have to go back to the Render layer Editor, I will do Ctrl+A here. You will see there is a master layer. There is nothing underneath it. If I click this Creates button, it gives me a little dropdown arrow.
If I expand that, you'll see that it makes a new contribution map. It must be numbered based on what was in the scene previously. Numbers don't really matter, but I will say pass contribution map. It's also listed right here in the menu. So now we can go back to these passes, Shift-select them, and then use this Associate button to draw from down and associating with that map, and now they are associated with that map. So we switch to mental ray. We have created five render passes that will be useful for composite, and now we are ready to set up the scene to start batch rendering.
- Working with image sequences
- Matching the 3D camera to video footage
- Lighting models in Maya
- Splitting a scene into multiple render passes
- Batch rendering
- Recombining render passes in an After Effects composition
- Setting up motion trackers
- Refining layers with rotoscoping
- Adding blur and effects
- Adjusting shadows and matte edges
- Using color correction
- Stabilizing shaky video