konstantin magnus Posted February 5, 2017 Share Posted February 5, 2017 I would like to simulate sliding rings on a swinging curtain rod using bullet. However they just fall through. I have set everything to concave. What did I miss? curtain.hipnc Quote Link to comment Share on other sites More sharing options...
Doum Posted February 5, 2017 Share Posted February 5, 2017 Hello, Using concave is not always the best solution. It is not really well handle by bullet in houdini. I would recommend 2 ways: Fracture each ring so all small pieces glue together will be convexe. The other solution is well explained here sphere packing for collision object. Good luck! Quote Link to comment Share on other sites More sharing options...
konstantin magnus Posted February 5, 2017 Author Share Posted February 5, 2017 It doesn´t need to be bullet. I am just looking for a simple and efficient way to do a RBD sim for this. Quote Link to comment Share on other sites More sharing options...
Noobini Posted February 6, 2017 Share Posted February 6, 2017 Hi, I'm a complete noob so in no way to teach anyone anything...but I'm just looking at your scene trying to learn something. If I change the Geo Representation from Concave to other options...a Sphere would be the most obvious....you'd see ONE gigantic sphere, this tells me it's not being seen as 6 rings (or 6 objects whatever the proxy collision shape is)...so the ring cloning needs to be looked at... Quote Link to comment Share on other sites More sharing options...
Noobini Posted February 6, 2017 Share Posted February 6, 2017 (edited) got it to this stage...got no experience with scale in Houdini....I had to make the rings a bit larger so I'm not simming with tiny scales... curtain_02.hipnc Edited February 6, 2017 by Noobini EDIT: what I don't get is in the Merge, if I change the order..ie, merge the Rings in first before the Bar (static), the rings will fall right thru....but with the Bar first then the Rings, then it works...could an expert explain please ? Quote Link to comment Share on other sites More sharing options...
Noobini Posted February 6, 2017 Share Posted February 6, 2017 ahhh, got it...it's the Relationship....Left inputs affects Right inputs Quote Link to comment Share on other sites More sharing options...
Atom Posted February 6, 2017 Share Posted February 6, 2017 Is there any way to make it more convincing? The rings don't appear to be in contact with the bar. Quote Link to comment Share on other sites More sharing options...
Noobini Posted February 7, 2017 Share Posted February 7, 2017 yes please any pro tips ? I've tried to lower the collision padding down to 0.002...but it starts to jump around too much... Quote Link to comment Share on other sites More sharing options...
Noobini Posted February 7, 2017 Share Posted February 7, 2017 ok, I've gone back to the orig author's tiny scale and forced it to work....slow as hell tho...but of course, that should be put down to my inexperience. I've changed the method for importing the rings into the DOP, using rbdpointobject, a ring is placed at each point of the line. Then I changed the solver to RBD instead of bullet, it's the only way I could make it work with such tiny scale with no explosion/falling thru... Now contact points are pretty good, tho can't find where the friction is to make em slide a bit more...In the solver Substeps, had to play around with Min/Max substeps and CFL condition... Any pro advice are appreciated, and no I didn't mean to hijack this from the orig author in anyway... curtain_03.hipnc 1 Quote Link to comment Share on other sites More sharing options...
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