petz Posted August 3, 2008 Share Posted August 3, 2008 does anyone know how to test the visibility of points in sop context? i have a situation where i need this to add attributes to points which are not visible from a specific position. thanks in advance, petz Quote Link to comment Share on other sites More sharing options...
sibarrick Posted August 3, 2008 Share Posted August 3, 2008 (edited) You can use the group or delete sops and go to the "normal" tab then you can use "backface from" and specify a camera. But that won't quite get you only the truly visible points, only the back facing ones. Might help though. The other thing you could try is aiming all the point normals at the camera then raying the points back onto the mesh itself, and deleting any that hit. hiddenPoints.hip Edited August 3, 2008 by sibarrick Quote Link to comment Share on other sites More sharing options...
edward Posted August 3, 2008 Share Posted August 3, 2008 If you truly have no surface information, then you can try this thread: http://forums.odforce.net/index.php?showtopic=5854 Unfortunately, the "simple" operator doesn't work too well in practice unless you couple it with the more complicated stuff that the paper does. Quote Link to comment Share on other sites More sharing options...
petz Posted August 3, 2008 Author Share Posted August 3, 2008 thank you both!!! @sibarrick your idea to reverse the problem and ray the points back on geometry put me in the right direction. to accelerate the solution i put it into vops because i need to test the visibility from more then one position. @edward nice example file! i have uploaded the file if someone is running into the same problem. petz point_visibility_test.hipnc Quote Link to comment Share on other sites More sharing options...
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