I'm trying to simulate a set of packed objects and use a custom velocity field created from a volume. I'm using a volume vop to add noise to the volume (which is merely a box being converted to a volume)and adding the “vel” vector parameter in the vop. I'm then creating a attribute from volume and creating the velocity attribute, “v”.
Inside of my DOPNET I'm using a volume source but when I plug it into the merge I'm getting the error “connection to input 2 is the wrong type”. I'm just not sure where to add the velocity from the volume to the object I'm trying to simulate. The object being simulated is simple and low poly just dropping onto the ground plane.
Any suggestions would be great! Thanks!

You could use the POP Advect By Volumes dop

Thank you for the reply mkps! I didn't think of that because I didn't consider using a POP for the RBD sim. I did pull that node up and try to drop it into the DOP network and make it work but to no avail. I figured it out though! After some extensive research I ended up using an attribute from volume sop and transferred the velocity data to points. I then used an object merge to bring in the transferred data and again transfer that information over to the object being used as a rigid object. I didn't want the new velocity to affect just the initial frame so I added a sopsolver and plugged that into the pre-solve. Inside the sopsolver I once again transferred the velocity data from the points which will allow the points to be transformed and the transformation and moving velocity information is introduced into the RBD simulation frame by frame instead of on just the initial frame.
Again, thanks for the reply!

As mkps said you can simply use POP Advect by Volume and there is no need to use sop solver or attribute from volume or etc as using of these nodes speed down your simulation.

This node transfers velocity from volume to rbd pieces per each frame.

Also if you like to have more control over this operation you can do this manually via POP Wrangle DOP or POP VOP DOP.

The thing you just need is Volume Sample Vector node in POP VOP or same function in POP Wrangle.

With this node/function you can grab velocity from Volume according to position of rbd pieces.

Here's an example file with the pop advect by volumes. You can get different results changing the advection type, method, etc.