Here is one guess - try making a solid bowl rather than single width polygon sides - i.e. take a cube, select the top poly CTRL -D it scale it in - CTRL D that and move it down - I am guessing like the normal RBDs which hate colliding with a grid but find a cube floor much better.
Do I make sense? S. _____________________________ Sandy Sutherland Technical Supervisor [email protected] _____________________________ ________________________________________ From: [email protected] [[email protected]] on behalf of Stefan Kubicek [[email protected]] Sent: 02 August 2012 18:25 To: [email protected] Subject: Simulate RBD and Simulate Bullet RBD issues Hi all, I'm having problems getting accurate collisions using Simulate Rigid Bodies and Simulate Bullet Rigid Bodies nodes when trying to fill a box mesh with spherical particles, namely: With simulate Bullet Rigid Bodies I get collisions in areas that are not occupied by any collision geometry. That is: collisions occur even though there is no collision geometry to collide with. See attached SI2013_Simulate_Bullet_Rigid_Bodies_Ghost_Collisions.jpg please. This happens independent of the collision precision. The geo is sane and there is nothing hidden either, I simply created a cube with some subdivs and removed the top polys so particles can fall in. Of course, I had to set "Exact Shape" for the collision, otherwise the particles would not even fall in but collide with the convex hull. The only remedy I found so far was to cut the box up into pieces for each of the walls and floor, and having particles collide with that. While this results at least in no "ghost" collisions, I still get a collision offset between particles and the collision geo, whic is also true when using the non-Bullet "Simulate Rigid Bodies" node, see SI2013_Simulate_Rigid_Bodies_Collision_Offset.jpg please. Ultimately, I guess I have two questions: 1.) How do I get accurate collisions with Concave meshes using Simulate Bullet Rigid Bodies without having to cut the geometry up? 2.) How do I avoid gaps between particles and collision geometry? I could not find any parameter controlling it. I must be overlooking something, otherwise it would be pretty useless. I know, there is Momentum, but one would assume the ootb tools, since they are there, are good enough for such basic stuff. Thanks a lot, Stefan -- ------------------------------------------- Stefan Kubicek Co-founder ------------------------------------------- keyvis digital imagery Wehrgasse 9 - Grüner Hof 1050 Vienna Austria Phone: +43/699/12614231 --- www.keyvis.at [email protected] --- -- This email and its attachments are --confidential and for the recipient only--
