How do you set up a Fractured static object, I want to cache my fracture sim and than add pyro and use the fractured sim as a static object, I can't use a static object however because the division for the SDF calculation would have to be set up really high.

I assume you have cached the dynamic fractured sim geometry to disk.

One way is to load in the RBD geometry sequence in to the new pyro sim using the collision tool from the modify container shelf. This will convert the cached fractured geo into a collision volume. Because this can be expensive, you can cache this out to disk prior to running the pyro sim. You of course can divide and conquer and turn each rbd I piece in to a collision container.

You'll also need to calculate vel volumes as well along side the collision volumes. They are required to help push the fluid about as the faster multigrid projection method in the core smoke solver used by Pyro doesn't use collision volumes but expects the vel field to be constructed to push the fluid out of the way.

You can also cache out the collision volumes from the rbd sim if they are Houdini RBDs and not bullet as bullet won't construct proper collision volumes unless the DOP sim requests this (such as a fluid solver running concurrent with the rbd solver). Note that collision volumes are inverted SDF's as the logic to combine them in DOPs sims is more straightforward.


Hope this helps.

As I'm using 10,000+ objects it must be automated, I'm using the RBD sim so caching out this data is an option, How do i do this? PS. Thanks for the detailed reply.

Using a second dopimport SOP you can fetch the collision volumes by specifying “Geometry/Volume” in the geometry data path. That would eliminate the need to create them again in the Pyro sim.

Cheers