Hi,

I lately tried the new rbd material fracture but came across some problems. I wanted to shatter a grid of 9 (small) windows; they should get hit by some metaball-forces in the first couple of frames.

1. I currently have 32 Gb RAM at my disposal; thats obvious not enough for major simulations, but even with my 9 small windows, Houdini crashes from time to time.
Funny enough, I was able to cache out the simulation without any problems, but I'm not able to view it in Flipbook. I'm sure there is still room for performance improvements, so if someone would have a glance at the hipfile, I'd be glad.

2. While shattering it sometimes seems, the frames and the glass are intersecting. I tried volume collision, voronoi fracture and default ray intersect, but somehow I'm not getting the right collision sometimes.

3. As an additional point, I wanted the glass to fully break, as soon as it gets hit by a force. My current approach is to set a force controlled by the angle but that didn't work out well. There are still giant chunks of glass which don't break, even if they hit the ground.

I attached the hip-file, so if someone would have a look at it, I'd be very glad.
Sorry for the slightly messy setup, I tried out some things…

Any help is still appreciated

Hi! Just working on destroying a wood door with rbdmaterialfracture and saw your post. I've downloaded your hipfile and my system gets very very slow (32gb too on a dell 7720 precision laptop). I think its because the for loop. I'm very new to houdini but why did you put rbdmaterial fracture inside a for loop? I think its making redundand proceses… I take it out of the forloop and everything seems to work.. But maybe I'm missing something.. I'm simulating a broken door with a lot more of pieces and works fine.

Hey david,
thanks for your Feedback.
I put it in for-loop, to get different break Patterns, but as I see now, you get differnt Patterns anyway. So you're Right, for loop is not needed. thanks

yes, that is for “fracture per piece”

yea, though I'm still struggling to get the activation right.
For now, I've cracks from the beginning. Is there a way to activate the cracks only then the windows get hit by the force?


Thought this could be possible with an i@active wrangle, but its not.

I think the best way is switching geometries on impact frame… active attribute is for make active or inactive fractured pieces on simulation.

take a look a this thread. Maybe it helps https://www.sidefx.com/forum/topic/44143/ [www.sidefx.com]

That may work well for opaque objects but due to the nature of translucent objects it won't work with glass.

However, for anyone interested I found a solution in thread:
https://forums.odforce.net/topic/22900-dynamic-ice-fracturing-solved/?tab=comments#comment-135580 [forums.odforce.net]

Worked great for me.