How to selectively make some RBD Fractured DOP pieces "passive"?

[catchyid]

Hi,

In a SOP network, I use Voronoi Fracture node to break a mesh, the node creates "name" primitive attribute to indicate pieces (e.g. piece01, ..., piece0N). In a DOP network, I create RBD Fractured Object to create the corresponding pieces.

My question: I want to select some pieces in a SOP context (or use any SOP nodes to proceduraly select some pieces) and then automatically set these pieces to "passive" in the RBD Fractured DOP? I know I can use "Activate Value" DOP to set some pieces to passive, but I am not sure how do the mapping from SOP pieces to DOP pieces?  For example, If I apply Voronoi Fracture on a wall, and I want the pieces at the base and corners of the wall to be passive, then I won't know which pieces numbers I should use in "Activate Value" DOP since pieces names are created automatically by Voronoi Fracture SOP?

I can think of one solution: just rename pieces in SOP to match my selection criteria and then use these names in DOP, BUT I am wondering if this is the right approach here? Is there a better way to select them directly in DOP Context? or Is there a better way to map this info from SOP to DOP?

Thanks,

 

[Juraj]

Hi,
for this kind of thing you can use i@active attribute. Bullet solver will recognize it.

To set i@active values: you can set values by Group SOP and bounding object / volume, or you can select packed primitives (fractured pieces) in viewport and blast them, then copy values from Blast node into next attribute wrangle node and set the attribute there.

[catchyid]

Thanks for your reply  Unfortunately it did not work and I am not what went wrong?

-is "active" a point attribute or primitive attribute? I've created an integer attribute "active" and set its class to "point" but did not work, so I changed the class to "primitive" and it did not work either?

-I am thinking, since each piece is made of may primitives/points, what is going to happen if some points of the same piece are set to active (i.e. has a value of 1) and others are set to 0?

Thanks

[Juraj]

Hi, check attached file. I recommend you watching bullet masterclass.

It seems like you used older workflow - without packed objects. Learn how to use packed objects, it gives you more speed and control.

 

jt_activate_rbd.hipnc

[catchyid]

Thaaaaaaaaaaaanks The Tutorial you pointed out is like a Rosetta stone  The pipeline shown in this tutorial is way better than what I was doing... Once more, thanks

[catchyid]

just opened your attached houdini file, and it shows exactly what I am looking for, thanks a lot, really appreciate it