haggi Posted March 23, 2011 Share Posted March 23, 2011 Hi, I exported a polygonal geometry from maya with my own exporter. The geometry seems to be okay in the UI and from the points, vertices and faces. But as soon as I render it - and its worse if I render as subdiv - I see some black patches. They disappear if I turn on the "Backface remove" switch. So it seems to be a self shadowing problem. But I cannot see any double faces or something like this. The problem should be visible in the attached image. So my question is: whats wrong with my geometry? I attached a scene with a .geo ascii file. Would be great if anyone could give me a hint how I can solve this probelem so that I can export my geometry correctly. Thanks a lot. geo.rar Quote Link to comment Share on other sites More sharing options...
~nature~ Posted March 24, 2011 Share Posted March 24, 2011 Hi,haggi I've tested your scene, I think it's caused by self shadowing but not due to your geo imported from maya. the same problem exists for the geo created in houdini as well. Obviously the self shadowing problem is produced when mantra subdivide the polygon at the render time. so the solution is: 1. scale down your geo to some extent. 2.crank up the ray bias. I guess both 1 and 2 are the same effects in the view of eliminating self shadowing. 3.subdivide your geo at sop level rather than at render time. Cheers. lianyi Quote Link to comment Share on other sites More sharing options...
haggi Posted March 24, 2011 Author Share Posted March 24, 2011 Thanks a lot for testing. Indeed my model is quite large, seems maya and houdini use different units. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.