Tim Saunders Posted August 17, 2006 Share Posted August 17, 2006 I posted this in the viz forum as well. I am working on a scene that has hundreds and hundreds of flowers and I have had to resort to using RPC. I want to render the rpc's in a separate pass and composite the plants in photoshop. So here is what I have tried so far. I render the scene without plants as one image. Then I assign a matte/shadow material to everything in the scene except for the rpc's (so I can have walls and fences subtracted from the rpc rendering). That cuts out the objects in front of the plants, but it doesn't save any alpha information. I have even tried rendering a shadow pass, but the image it renders is completely black. Anyone know a way around this? Link to comment Share on other sites More sharing options...
Chad Warner Posted August 17, 2006 Share Posted August 17, 2006 Make sure you have "Opaque alpha" unchecked? Link to comment Share on other sites More sharing options...
Tim Saunders Posted August 17, 2006 Author Share Posted August 17, 2006 Ya, I tried that, but the alpha channel it generates includes the rpc's as well. Here is the test scene I am working with. The first image is the end result I want, but I rendered everything together. The actual scene I want to use the method to composit with will have tons more planting - hence the reason for trying to figure it out. the second image is what I render with the matte/shadow material applied to everything except the rpc's. that is exactly what I want, but I just can't seem to figure out how to composite that into my base rendering which is the 3rd image. Link to comment Share on other sites More sharing options...
Chad Warner Posted August 17, 2006 Share Posted August 17, 2006 I'm guessing that you are saving the matte/shadow image in a tga or tif format? If you have it set up right, the only alpha channel info you should have is that of the RPC's. Link to comment Share on other sites More sharing options...
Tim Saunders Posted August 17, 2006 Author Share Posted August 17, 2006 I got it! The whole problem is in using hte vray randerer. When I switched to scanline...whala! thanks Chad. Link to comment Share on other sites More sharing options...
Chad Warner Posted August 17, 2006 Share Posted August 17, 2006 If you are using Vray, you have to set the objects to be "matte" under the vray properties box, or use a VrayMtlwrapper and do the same thing there. The settings are different than the matte/shadow material though. Link to comment Share on other sites More sharing options...
bou^bou Posted June 14, 2007 Share Posted June 14, 2007 HI hum, i still have the same problem I 'm trying to make a default scanline render pass (tga format) For my RPC elements with Their shadows, using matte/shadow for the rest of the scene, the shadow did not appear... i think ther is a problem with Rpc Shadow plugins and the Matte shadow material... hope that i'm wrong..... Link to comment Share on other sites More sharing options...
Tim Saunders Posted July 3, 2007 Author Share Posted July 3, 2007 You have to use scanline renderer for your matte shadow pass. Link to comment Share on other sites More sharing options...
Justin Hunt Posted July 4, 2007 Share Posted July 4, 2007 Also RPC's work better with Scanline. As a tip with RPC's, load the RPC into the material editor, turn off the self illumination and change the shader type to Oren-neylar blinn. Then you can dial down the diffuse level to darken the RPC's further. If you use Mentalray then you can drop an AO shader into the diffuse level slot, which will give a nice "grounding" feel the the plants. JHV Link to comment Share on other sites More sharing options...
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