Problems, problems, problems (Part2)

Okay the Matte Painting is done, the CG bridge is in building state it seems like everything's cool. Let's just do a camera projection of the Matte Painting to give it some depth! Nothing can go wrong there, I've done it quite a few times in After Effects without any problems, well this time I'm using Maya, but that should only make it easier! WRONG!!!

Setting up the projection camera and the image plane is fairly simple. Shading the objects (simple polygon planes in this case) on the other hand isn't. Because the painting is already lit you don't want the material to receive any kind of lights or shadows and the surface shader is therefore perfect for this scenario. Unfortunately the out transparency node on surface shaders doesn't work with projections! And that is not just me being young and stupid and inexperienced my 3d and CGI tutor Georg was just as baffled as me. I found a relatively good and easy solution, but it only works when rendering in Maya Software. By plugging the projection node straight into the surface material node of the shading engine you can avoid making a material but still get the projection onto the geometry. No lights, no shadows, just the plain projection with an alpha channel (just make sure you only project everything once, so turn projection off when you assign the alpha file to the out transparency!) . Only downside as I said earlier you can't render it in Mental Ray because of a really weird (but kind of cool) red glow around the edges. Apparently it's Mental Ray's way of warning you that you don't have any materials assigned(DUH!) Another way of doing it (I have to give mighty George Finch full credit for this!) using a ramp shader instead. Just plug the projection file as a projection into the colour node and the alpha file into transparency, turn off all the light and reflection related attributes and it's done. It works with transparency and in Mental Ray. Hey! Another day of excessive swearing and frustrated any-object-nearby-throwing fun over! But there is more to come when Problems, problems, problems continues for part 3.