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View Full Version : Shadow Pass with Transparancy intact???

SpiralFace
01-17-2007, 07:59 AM
Ok, so here is my situation;

I have a game character that I am rendering for demo reel purposes, and I want to do some beauty passes on it by rendering out the thing with mutiple passes to composit them together later. To aquire this, I need to utilize multiple rendering modes. Currently this is what I have;

Game Character: Needs to be rendered in Hardware render mode, to not only show what it looks like in real time, but in my version of Maya, it is the only mode that supports Tangent space Normal maps in the renderer.

Pedistal: To give the guy a pretty base, I've used some nice procederal textures to help with the presentation of him on my reel. Of corse, this requires me to utilize iether Mental Ray or Sofware rendering to accomplish things like the Fernel effect Reflections.

Shadow/ Ambient Occlusion: Here is where I run into the issues. In order to aquire soft shadows on the Figure, I must render in Software or Mental ray mode to avoid harsh vertex shadows. Problem is that as I use the "use background" shader, it will render the shadows over parts of the figure that are normaly transparent due to a map that is applyed to it on its base color map.

I'm wondering, is there a way that I may apply a transparancy map or a mask to both the "use background" color, and an ambiant inclussion shader in order to prevent it from rendering in the areas that are transparent on the figure? This way when I composite it together, I don't get weird artifacts in areas that are transparent.

If not, how whould you guys approch this issue?
SpiralFace
01-18-2007, 08:23 PM
No one knows?

Ok, I'll try to re-phrase the question,

When doing Ambiant inclusion and soft render passes for portfolio work, how would one go about correctly linking the Transparancy map to these shaders in MAYA.
MaNdRaK18
01-19-2007, 05:11 PM
Mib_amb_occlusion doesn't suport transparency. Try Mib_fg_occlusion instead.
SpiralFace
01-19-2007, 08:23 PM
Mib_amb_occlusion doesn't suport transparency. Try Mib_fg_occlusion instead.

Thanks, that worked like a charm

Mib_amb_occlusion did have a transparency setting through the surface Shader node you have to use, but It only rendered the transparent Silloete where if there where overlaping peices (such as a tattered dress over a leg in my case) it rendered it as if it was'nt there, but this seems to work fine.

I guess I'll just use these Ambiant passes to fake the soft shadows on the figures since I can't get the use background to get transparency's from it and use the Alpha shadows.

Does anyone have any alternative Ideas where I can just render out just the Alpha shadows on the figure where I can preserve the transparency's of the figure below it?
SpiralFace
01-20-2007, 12:28 AM
So I've been rendering with the Final Gather Occlusion passes and have run into an issue with the transparencys. I've gotten this problem,

http://img.photobucket.com/albums/v641/shadow_s1ayer/AmbiantOcclusion.jpg

It seems like its just translucent though, so I'm thinking it might just be some kind of speculer color or something. But there are no controls for Speculer or anything on the Occlusion node or the Surface shader itself. So if anyone has any Idea what this is please let me know.

Thanks for the help so far though guys.
rygoody
01-20-2007, 12:41 AM
I'm pretty sure ctrl_occlusion supports transparency
SpiralFace
01-21-2007, 12:07 AM
I'm pretty sure ctrl_occlusion supports transparency

Where is this shader located?

The only Occlusion Shaders I can find in Mental ray are the mib_amb_occlusion, and the mib_fg_occlusion. Where can I find this shader your talking about?
o-v
01-21-2007, 12:49 AM
check www.mymentalray.com -> shaders...

ctrl_occlusion is a shader by francesca luce.
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