glue network and deforming mesh

[pau22]

Hello!

I have a prefractured animated mesh and I'm using bullet solver. When I simulate as a static mesh everything goes fine but when I switch to "create deforming active objects" in the RBD packed object I get odd results and the glue network seems not to be working.

I've realized that the glue network only is created once in the beginning of the simulation. Should it be updated every frame if the mesh deforms?

 

Thanks in advance!

 

[Farmfield]

Yes, you would have to do that. Constraints are lines, two points with a name point attribute telling them which piece to attach too and two primitive attributes, one for constrain_type for position, rotation or both (not the type as in glue, pin, cone, that's in DOPs) and a constraint_name which is the data name you link it to in the constraint network node in DOPs. (*)

So if you have a changing mesh, you will need to reposition the points per frame - but you don't have to do that manually, if you have a setup procedurally generating the constraints from the mesh, you just need to set the "overwrite with SOP" in the constraint network node in DOPs. If you don't have procedurally generated constraints or want to control them very specifically, you gotta set that up in a SOP solver in DOPs.

(* That's the basis for a constraint. Then you have a ton of point attributes you can use to set strength, constraint angles, etc, but you gotta read up on that in the constraint network help, it's just too much to cover here.)

[pau22]

58 minutes ago, Farmfield said:

Yes, you would have to do that. Constraints are lines, two points with a name point attribute telling them which piece to attach too and two primitive attributes, one for constrain_type for position, rotation or both (not the type as in glue, pin, cone, that's in DOPs) and a constraint_name which is the data name you link it to in the constraint network node in DOPs. (*)

So if you have a changing mesh, you will need to reposition the points per frame - but you don't have to do that manually, if you have a setup procedurally generating the constraints from the mesh, you just need to set the "overwrite with SOP" in the constraint network node in DOPs. If you don't have procedurally generated constraints or want to control them very specifically, you gotta set that up in a SOP solver in DOPs.

(* That's the basis for a constraint. Then you have a ton of point attributes you can use to set strength, constraint angles, etc, but you gotta read up on that in the constraint network help, it's just too much to cover here.)

Ok. Thanks for the explanation. I've set the "overwrite with SOP" flag to 1 and disabled the time shift called "fetch_from_initial_frame", so that every frame it generates a new network.

However, it seems that the glue network is delayed 1 frame, so it does not match the mesh because it's created after simulating each frame. Should I use a different approach?

 

[Farmfield]

What needs to be tweaked for stuff to work is of course individual for each setup, but if you conclude the issues you have are connected to it being delayed one frame, then you of course gotta timeshift it in place.

I'm in the middle of doing a thorough refresh and read-up on my dynamics skillset, and this last week I lived and breathed constraints - you caught me at the right moment so to speak.