Dynamic constraint network creation

[c0y]

Hi,
I'm trying to make a dynamic procedural constraint network for rbd packed object on a deforming mesh.

I'm importing an animated object I fracture, and copy the animation.

 

Then I'm creating some activation groups at different time.

This scene is just a simple example just to understand the process, but the activation groups could be anything else (like an angle threshold, a color threshold, etc.).
Then I'm building the constraints network, which are animated.

And here is the hard part... I don't know how to deal with it.
The goal is when a group activate fragments, it take their current position, create a constraint network between them (hard, glue for example). The created constraints could be breakable (by strength or angle, etc).

 

But I'm not sure to take the good way to do it, especially with my constraints network.

Is anybody ever done that kind of effect before ? Any clue on how I should create this kind of constraints ?

Thanks !

 

RBD_animated_constraints_01.hip

Edited January 14, 2018 by c0y

[arifakca]

https://sidefx.com/tutorials/houdini-dynamic-fracture/

[c0y]

Thanks for the link,

the problem is that I want to keep constraints between my broken groups :

@Frame = 25, the first group make the pieces active, and create constraints between them, that can be broken afterward.

@Frame = 50, the second group make the pieces active, create constraints, and keep also the constraints of the first group.

I did a solver to try to create a connectadjacentpieces for my constraints at these specific frames.

One of my problems is that when you have a moving constraint network, you need to put the "override with SOP" option at 1 (to update each frame), but when you do that, the sop solver that break the constraints is also updated and the broken primitive re-appear, so the object doesn't break ! I can't find the way to make the 2 things work... 

[c0y]

Hi,

here is a clean hip file of what i've described before :

in one case, I can't break the fallen pieces (due to "overwrite with SOP" set to 1) because the @angle or @force attributes are updated and if the value goes below the threshold, the constraint re-appears.

in the second case, the update of the attributes (like position) is problematic because I can't update the relationships_geometry because some primitives has been removed... the network explodes.

So if someone have a solution... or maybe this is not the right way to do that kind of effect.
I need to keep things procedural : if I add other groups above, the effect should work.

Thanks !

RBD_animated_constraints_06.hip