I know I briefly referenced it previous posts, but now I will be going a little bit more in depth on the purpose of those two extra render layers, 'PrepforShad' and 'EnvironmentShad'.
So I set up my PrepforShad layer with my ground plane and sphere. By looking through my key light that I set up at the beginning of the project, I'm able to look at my scene from the perspective of the sun. I create an new camera from this position that I will render from called my KeyLightCam. This way, I know that the perspective of the shadows are correct. I make sure that I've set the primary visibility of my sphere to be off then render out my image.
Then I load my image into photo shop and use the Select > Color Range option to select specifically select my shadows. Then I create a new layer and paint it 100% red. Then I create a background layer and fill it with 100% black and I should get something like this. But as you've noticed from my previous post, just this alone doesn't give me the result I want. It picked up all the bumps, cracks, and dings in the side walk and muddies the overall image. So what I've had to do was go in and clean it up and erase all the excess red so that I'm getting a clear shadow shape. It was time consuming, yes, but to save myself to work, I only touched up the areas where I knew my sphere would be rolling through.
After that's done, I save out my image and head back to Maya. Then I set up my EnvironmentShad layer. I add in my ground plane and sphere and assign a Maya's surface shader to both and project my painted map onto them and set the perspective to be from my KeyLightCam. Then I make sure the primary visibility of my ground plane is off, and set up my project to be rendered. As you can see I'm getting a much cleaner result than I was before.
Once I re-render my sequences with the cleaned up environment shadows I read in them into Nuke. Since I've already set up my node structure, all I had to do was reload my image sequences. This is the current result I'm getting. The cleaned up painted shadow map made a huge difference and I'm a lot more satisfied with the result. Now all that's left is a little fine tuning and then it's good to go! Stay tuned!
