RBD of an animated imported object

[Fede_Pasticcio]

Hi guys,

I have a big problem with destroying an external object (a shield) that contain an animation. I've imported it as alembic. I've timeshifted it at the first frame, then fracturated the shield. Attatched this part to the first input of the point deform node, in the second the rest pose of the shield and in the third one the animated geo. The purpose of the rbd simulation is only to fracture a little part of the shield as the shield had been hit by an ax.  To achieve that, I've painted where the ax would it and make this mask attribute equal to active attribute for the sim; then assemble it. Basically what happens is that when the pieces are falling down and even if they are flying, they move according to the shield animation.

Maybe ther is another way to prefracture it and give it the same animation.. maybe with a vector and copy to point to it, but i don't konw .... I'm really stuck.. If anyone has any ideas that would be great!

I've attached the file of what happened.

Thank you in advance for the attention!

Fracturing_Shield.hipnc

scudo.abc

[underscoreus]

If possible I'd recommend trying to avoid deforming active objects and deforming constraints if at all possible. Maybe you could just freezeframe your fractured geometry on the frame the ax is supposed to impact the shield and set all the fractured pieces of the shield as "active = 0" except for the area where the ax impacts which you'll set as "active = 1". If you want to have the active pieces collide with your animated shield simply add a version of your shield where you've removed the parts of the shield that are active as a deforming static object. You could also probably do some stuff to have the active pieces of your shield inherit some of the velocity from your animated shield by transferring and mixing in some of the velocity you compute for it in sops with the "Trail" node into the rbd sim itself with a pop wrangle or something.

[Fede_Pasticcio]

Thanks for the reply!

Yeh at the end I followed your advice and it works. We are making a full CG short film for my last university course and in this scene the break has already occurred and therefore this has made my work easier. For the collision, perfect, it happens right thanks! After that I added small pieces of wood by copying them onto the spawned pops from the fracture.

Thank you very much for your availability!