Andy_Ireland Posted March 27, 2012 Share Posted March 27, 2012 First time posting here and I have what seems like it should a be simple problem but I've been testing various things over the last few days and have had no joy The problem I keep coming up against is to do with collision guide geometry rounding off corners within a simple frame shape - a large cube with a small cube cut out of it, see attached. Im using Houdini 11 Ray Intersect and even with the collision guide geometry divisions turned up to very large numbers eg 400 400 400 the corners are still rounded and the file becomes slow to work with... Any suggestions greatly appreciated! Quote Link to comment Share on other sites More sharing options...
edward Posted March 27, 2012 Share Posted March 27, 2012 No attachment? In any case, make sure your box is aligned to the world space axes when creating the sim object. Quote Link to comment Share on other sites More sharing options...
Andy_Ireland Posted March 28, 2012 Author Share Posted March 28, 2012 No attachment? In any case, make sure your box is aligned to the world space axes when creating the sim object. Thanks Edward, it is aligned to world space, messed up the attachment last time, should work now Quote Link to comment Share on other sites More sharing options...
edward Posted March 29, 2012 Share Posted March 29, 2012 Try various toggles on the clean sop. Maybe you've got bad geo there. Quote Link to comment Share on other sites More sharing options...
Andy_Ireland Posted March 30, 2012 Author Share Posted March 30, 2012 Thanks again Edward, it helps a bit but doesn't fix the problem unfortunately. I can just glue a few implicit boxes together for what I want to do which works well but was just wondering if there was a better solution Quote Link to comment Share on other sites More sharing options...
murc Posted March 31, 2012 Share Posted March 31, 2012 No attachment? In any case, make sure your box is aligned to the world space axes when creating the sim object. Hi Edward, I think he means the rounding of hard edges when the SDF is calculated for collisions; see attached Don't recall seeing any particular tutorials/info anywhere on generating accurate collision geo, usually just something I have to play around with and live with the inaccuracy in the end hoping it isn't too obvious collisionCornerInaccuracy.hipnc Quote Link to comment Share on other sites More sharing options...
ryew Posted April 1, 2012 Share Posted April 1, 2012 Hi guys, I have a similar problem trying to get accurate collision geo for a FLIP sim. The tightest result I've gotten is by using Ray Intersect Mode, Division By Size with Divisions set to 0.0125. It's pretty close, but the gap is still noticeable when I render the meshed particle fluid flowing over it, particlarly when small splashes hit the surface and either hover over it or penetrate it and disappear. Does anyone have suggestions for improving the accuracy of FLIP collisions against RBDs? I've tried using offsets (both positive and negative) but that doesn't help get a clean/tight intersection Cheers flipcollisionsurface_inaccurate.hipnc Quote Link to comment Share on other sites More sharing options...
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