Hi,

I have imported geometry using Alembic Archive from Blender 3D. The model was parented to a null with keyframed transforms in Blender, the geometry moves as expected in Houdini. I used voronoi fracture within Houdini to use in a RBD sim.

My issue is that when I try to run an RBD simulation on the geometry, Houdini recalculates the IsoOffset and Voronoi fracture on each frame which makes playback impossible.

I assume this may be due to the way that Alembic files are imported. Since I don't see any animated transforms on the mesh or parent objects I guess that on each frame the object is imported with new coordinates baked in for each point from the archive?

Is there anyway to stop the recalculations on each frame whilst keeping the animation? My attempt to fix this has been to import an animated null and to patent it to a single Alembic frame of the geometry however I am facing a different set of issues by doing this.

Any help would be greatly appreciated. Please excuse my incompetence

p.s. The naming of the abc file is wrong, the file does also contain the geometry.

That is the way the Voronoi Fracture node works. It will re-calculate every frame for deforming geometry. You may want to check out Tokeru, there are some example files dealing with RBD and fracturing.
http://www.tokeru.com/cgwiki/index.php?title=HoudiniDops#RBD_packed_prims_and_deforming_geo [tokeru.com]

If you are unaware of the mPlay viewer, it is useful in these situations. I often click the Render Flipbook icon instead of simulating. The flipbook will cook your geometry every frame and also screenshot your viewport. Then at the end of your simulation you have a way to play it back at real time. This technique locks you into a view angle, however, so setup your viewport with a good view before you try this out.