Fakit Posted February 26 Share Posted February 26 (edited) Hello everyone, A simple issue that I don't understand : RBD Explosion. You'll see in the setup attached : - A base geo (head) - A quick fracture work (mask + fractures) - RBD Configure (with active bound) - A bullet solver Then, I feed an AttributeAdjustVectorFloat for the Velocity (3rd input/proxy). --> Frame 1 = Velocity Data OK --> From Frame 2 = v@v = {0,0,0} If I deactivate "constraint" in the RBD Material Fracture, then, I have Velocity data. Normal --> No constraints. But even If i put 0.0001 for the Glue constraint : Same ! --> Frame 1 = Velocity Data OK --> From Frame 2 = v@v = {0,0,0} As usual, this is possibly a very simple and dumb thing. Let me know if you can enlighten me. Thank you ! Ps : Here's a simple tutorial about that. Simple_RBD_Explosion.hipnc Edited February 26 by Fakit Quote Link to comment Share on other sites More sharing options...
Sepu Posted February 26 Share Posted February 26 is because you have the constraints on in the fracture, if you do not need them just disable them, pure velocity wont break the constraints. Quote Link to comment Share on other sites More sharing options...
Fakit Posted February 26 Author Share Posted February 26 Thank you for your answer @Sepu ! Yeah that's what I saw. It works If I disable the constraints. But let's say that I need them. I should be able to break the constraints with velocity with a very low Glue value no? Thanks Quote Link to comment Share on other sites More sharing options...
Sepu Posted February 26 Share Posted February 26 you can not break as I said above glue constraint with just velocity. You need to create some kind of impact like things colliding with them, events, falloffs, etc. Have a look at this and it will give you quick overview of constraints Quote Link to comment Share on other sites More sharing options...
CarlosGuzman Posted February 26 Share Posted February 26 Hi Fakit, you can break glue constraints based on velocity, in order to achive this you will need to transfer the velocity to the constraint network and remove points or prims based on a rule. please have a look. Simple_RBD_Explosion_CG.hipnc 1 Quote Link to comment Share on other sites More sharing options...
Fakit Posted February 26 Author Share Posted February 26 Thank you for your answers! @Sepu I'll take a look at this one for further understanding in case I missed something. @CarlosGuzman Thank you for the explanation and the file. Really good method to break constraint with velocity. So this is a clear statement, as said @Sepu : We can't break constraint with velocity only. We need to break the constraint as you have done in your file, with the help of a threshold, but not with velocity only. If we apply any velocity on a pre-fractured mesh, the constraint will not break by itself. So I can also see a simple method where we can use the "Break Thresholds" in the RBD Bullet Solver, with the At Frame. (See attached file) At the end, it's just a matter of breaking the constraints at one moment, to allow velocity to work. Thank you for your help ! Appreciate it Simple_RBD_Explosion_FKT.hipnc 1 Quote Link to comment Share on other sites More sharing options...
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