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Lighting and Rendering with mental ray in Maya with Eric Keller shows how to master practical mental ray techniques for rendering models created in Maya. This course walks through the most efficient and innovative mental ray techniques, including direct versus indirect lighting methods, creating different types of shadows, using the new ShadowMap camera, and reusing shadow and final gathering maps. A chapter on optimizing render times and enhancing render quality is also included. Exercise files are included with the course.
So now I can check to see that my batch render has completed, and I'll just do that by opening the Script Editor. So, I'm just going to click down here in the lower right side of the Maya interface, double-click to bring it up, and if I scroll up in the History here of the Script Editor, I can see Rendering Completed, and the images have been put into my project directory for this, is Exercise Files, and the image sequences have been put in the images directory. So at this point I can go onto After Effects and start putting together a composition.
So, I'll minimize Maya. This is my Maya project directory called Exercise Files. I'm going to double-click on the images directory, and you can see I have several image sequences here. I have the colorMask, which was created with the color mask render layer. So no passes were created for this - it was just a single render layer with no render passes - but I do have my toy render layer. If I double-click on this, I can see that I have a MasterBeauty pass, toy Ambient Occlusion, AO stands for Ambient Occlusion, toyDiffuse, Reflection, and Specular, and these are all the passes that I created. And if you remember when I was in Maya, and I set these passes up - I'll go in the Render Settings window and click on the Passes tab - you can see that this is using exactly the names that I gave each one of these render passes.
So, it's a really good idea to give your render passes descriptive names, especially when you bring them into After Effects and you start putting together your composition. You'll have an easier time keeping your layers straight. So, I'm going to minimize this, and let's go over to After Effects, and I started putting together a composition here. And to bring these file sequences in, you just go to File > Import > Multiple Files, and I'm just going to my Exercise File project, under images. Here are the image sequence.
So, for instance, if I want to import colorMask, I'll just select the first one in the sequence and make sure IFF Sequence is selected and just do Open, and it'll bring them in, and I already have that actually in the project. So I'll close this. I just wanted to point out a couple of quick things about how I've arranged my composite. This is just a very quick demonstration composite. I've done a couple things. I've used the colorMask as a way to separate individual elements for editing. For instance, I have an adjustment layer that has a number of effects on it.
So, if I look at the Effects Control, I have a Hue, Saturation and Levels, just to do quick color correction, but I've set the Alpha Matte to the colorMask layer. And remember this layer basically has the toy in red, the ball in green, and the floor in blue, and I've Set the Matte to the Red Channel. So, now this colorMask layer is using the Set Matte effect, so that only the Red Channel is visible on the Alpha. So, what that means is that if I go back to my composite, and I start to make adjustments to the effects on the adjustment layer, as I start to adjust things like the Saturation, it's only being applied to the toy, because I am using the colorMask as a way to extract the toy, and it's just a matter of convenience.
I can continue to make adjustment layers and add other copies of the colorMask if I want to separate effects for the chrome ball and the floor and so on and so forth. I have several pre-compositions here: one for the toy and one for the ball. If I double-click on the toyComp, you'll see this is what it looks like, and pre-comp is made up of the render passes. So, for instance, I have the Specular on top and the mode set to Screen, so this allows me to make adjustments to that layer by itself.
So, for instance, if I wanted to do something like a glow, just on that Specular channel, I could do that, because the Specular pass has been separated from the rest. And a better example might be if I wanted to change the color of that Specular highlight, I could go and add a Hue and Saturation effect, turn on Colorize, and now I can start adjusting colors to that Specular highlight, and so on and so forth.
So that's the advantage of having these passes separated. So, if I turn off Specular, you can see, this is the Diffuse and the Reflection and the Ambient Occlusion. I have the Reflections at the Screen, so I can turn that off. Now, we're just seeing Diffuse and Ambient Occlusion, and if I turn off Ambient Occlusion, we'd just see the Diffuse. The Ambient Occlusion pass is set to Multiply, and this is what's creating some of the shadow in the eye sockets and the other parts. So, if I turn that off, you can see it's cutting off some of that bounce light, giving it more of a recessed look there.
So, that's the advantage of compositing with render passes. You have more control over how you can adjust the animation after the rendering is complete. So, of course, now I can take a look at the entire sequence. I'm just going to adjust that Saturation a little bit and do a RAM Preview. So, here's the finished animation on the turntable.
One thing I'd like to point out quickly: You may notice the way I set this up, if I take a look at one of these render passes, for instance, the toyDiffuse layer, it says Millions of Colors plus Straight, meaning that it has an Alpha Channel. So, I double-click on this and take a look at the Alpha Channel. This is saying that the Straight means that it does have Alpha Channel, but if I display the Alpha Channel, then I see all white.
So, there's nothing in the Alpha Channel, and the reason is it is because, when I set up my render pass, I'll just double -click on the toyDiffuse render pass, I had Number of Channels set to 3. So, if you want to include an Alpha Channel with that render pass, don't forget to set this to 4. In this case, it was fine, because I'd actually created that extra color masking render layer, and I could use the color mask to create all of the Alpha Channels that I need to, but make sure that your render pass has an Alpha Channel included. Don't forget to set this to 4; it's a very easy mistake to make.
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