Voronoi Fracture Dynamics Not Working When Set To Trigger On Collision

[Adam Trachtenberg]

The “on collision” setting simply means that nothing will happen until something collides with your fractured object, so it sounds like it’s working properly.

[David Fleury]

So why is the object not falling to the ground? It is just sitting there. Why is the rigid body tag not causing it to react to gravity?

Thanks for your help.

[Brian Jones]

you need to change On Collision to Immediately – then it will start to fall immediately – if you are having problems getting the object to fall but not to start breaking apart until it collides with the floor that’s an older pre-voronoi fracture problem. Basically you need to turn off Self-collisions until it collides, it’s possible to use xpresso to do that like this

12345_xpressotokeepvftogetheruntilimpact.c4d.zip

[David Fleury]

Ahhh, ok I will give your suggestion a look. Thanks for the project file!

[Din Iulian silviu]

You are right, but why the object looks fractured before the collision impact?

printscreen.png

[Brian Jones]

when you put a transparent texture on the voronoi fracture it reveals what is always true, the one object is really many. That doesn’t matter if it’s not a transparent texture as long as it doesn’t separate too soon due to self collisions… here though I tried a number of things to get it not to break too early (turning the VF from Enabled Off to On looks like it should work in the viewport but the result in the renderer is wrong) so ended up with this.
I went with turning Hull only Off and On in the VF. It seemed to take VF/Sources tab Distribution Type being Inverse Normal when I tested on a sphere but substituting with a ‘glass’ type object that doesn’t seem to be true…

12625_xpressotokeepvftogetheruntilimpactwithtransparency2.c4d.zip

[Din Iulian silviu]

Thank you very much!

[Din Iulian silviu]

I wonder how, if it is possible to create an inverse effect, so …
I have a glass and a bowling ball who will hit the glass, I want the glass to remain the same and the bowling ball to break into pieces,

How it is possible?

[Brian Jones]

if the bowling ball is dropping onto the glass it’s just a Collider tag on the glass (no fracture) and the same setup as earlier in the thread (12345_xpressotokeepvftogetheruntilimpact.c4d.zip) on the ball. If the bowling ball is rolling that would be different

[Din Iulian silviu]

Thank you,
This is what I want, the ball is rolling, then hits the glass and breaks in pieces.
It is possible?