I want to produce a fire animation in Blender that cycles, the first frame being the same as the last.

I've tried following a youtube tutorial Looping Smoke-sims in Blender | Quick Tip on Simulations but I can't get the procedure to work.

I'm wondering if it's possible to manipulate vdb caches, either from within Blender or via stand alone tooling.

Suppose I have a cache of 250 *.vdb files, corresponding to 250 frames of animation. Frames 1-50 animate the fire starting up and frames 200-250 animate the the flame dying out. These effects I achieve by keyframing the fuel for the Flow object.

What I'd like to do, within Blender, is to take a create a volume Add>Volume>Import OpenVB and import to it frames 50-250. Then somehow 'merge import' frames 1-50 into that same newly created volume, but starting at frame 200 of the volume. That way, the start of the volume should be identical with the end without any discontinuity in between.

I can't see any such menu in Blender to do that however. Nor can I see any option to join volumes, in the same way that objects can be joined.

Blender 3.3.1

  • $\begingroup$ I don't think blender can merge (mix) two VDB files ... only one harakiri I can imagine :) Import two VDBs (or for loop just Duplicate with changed Start frame), add Cube with modifier Volume to Mesh - target first VDB, do the same for duplicated, then for first Cube add Boolean modifier > Union ... this creates merged two meshed VDBs ... now add Geometry Nodes modifier > Mesh to Volume ... sure, this is not serious A, but it did something :) ... If you are looking for stand alone tool your Q could be closed here, since this site is maintained to Blender. $\endgroup$
    – vklidu
    Oct 29, 2022 at 20:41
  • $\begingroup$ Speaking to the Tutorial ... I became confused ... I thing just Import VDB, duplicate, make unique data block and change Start frame in properties should be enough (sure in Repeat mode). $\endgroup$
    – vklidu
    Oct 29, 2022 at 20:55


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