Hi,

from FLIP workflows I'm used to inject custom velocities into the collision geometry to create some more breakup.

Now I did the same for my vellum grains sim but it didn't work at all. Even when I completely deleted the velocity attribute the sim still behaved the same, so I guess the calculation of the collision velocity happens inside the solver?

As a workaround I tried to manually sample collision velocity using a wrangle inside the DOPnet which kind of works but seems a bit unstable at times so I was wondering if there is a more native way to customize the collision velocities for vellum simulations.

Thanks!

I believe if you have a v attribute on collision surface points it should override the velocity calculated at sim time, maybe try putting some extreme values there to check, the effect could just be very subtle with your current values. If you don't have the attribute then the solver will try to calculate it from the change in point positions (so it will make a mess in changing topology cases).

FedorK_FX
I believe if you have a v attribute on collision surface points it should override the velocity calculated at sim time, maybe try putting some extreme values there to check, the effect could just be very subtle with your current values. If you don't have the attribute then the solver will try to calculate it from the change in point positions (so it will make a mess in changing topology cases).

I tried that as well, multiplying the velocity by something really high but even though it displays the velocity on the collider in the DOP net, it does not affect the particles