chibley Posted November 6, 2014 Share Posted November 6, 2014 Hello, I am trying to render out a simple scene which comprises of a sphere with a partially reflective material on top of a backplate which depicts a table which the sphere sits on. I have included an environmental light with an HDRI environment map and two area lights which are in the approximate positions of their real-life couterparts. I have assigned a matteshadow shader to the table surface in order to 'catch' any shadows created by the sphere, and am getting shadows on the table surface when I composite the CG on top of the backplate: The problem is that I am also getting the reflection of the matteshadow (table top) holdout on the reflective sphere, and would like to instead have the sphere reflect the true texture of the table top surface. Now I know in Maya I can use mip_matteshadow and mip_cameramap shaders to successfully get this effect, however I have no idea where to start in Houdini for this. Is there any way of getting the diffuse of the table top geometry to simply read the backplate from the camera? I know how to camera project and bake out textures from the backplate in Houdini however I have no idea how to combine this technique with the matteshadow shader in order to get the effect I need. Anyone here know a method for doing this? Any help would be much appreciated! Chibley. Quote Link to comment Share on other sites More sharing options...
jkunz07 Posted November 7, 2014 Share Posted November 7, 2014 If you could attach the file it would be helpful. There is no need to use the matteshadow shader, you can just assign a regular diffuse shader to the table geo. In that diffuse shader you can do the camera projection of the backplate so that the sphere will reflect the proper colors. The last step is to make the table geo a "phantom" or "matte" object, depending on what your trying to do with the scene one may make more sense than the other. In the current situation they both should behave the same. Quote Link to comment Share on other sites More sharing options...
jkunz07 Posted November 7, 2014 Share Posted November 7, 2014 If you want the table to receive shadows you can either use a shadow matte aov and do it in comp, or use the matteshadow shader but disable the table geo in the sphere reflection mask. Quote Link to comment Share on other sites More sharing options...
chibley Posted December 8, 2014 Author Share Posted December 8, 2014 If you want the table to receive shadows you can either use a shadow matte aov and do it in comp, or use the matteshadow shader but disable the table geo in the sphere reflection mask. Hi John. Sorry for the late reply. I tried what you had described and everything worked wonderfully. Thank you for your help. Quote Link to comment Share on other sites More sharing options...
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