Hi, so I've got a pyro sim run by one of our artists here, that has 2 separate sources, one creating fire with no smoke/density, and the other emitting only smoke/density.
The sim starts out with the fire only and no density, and then the density source is keyed on after a certain frame.
After this is simmed out, it is converted to VDB and at that point all the voxels for density dissappear until the frames where the density are being emitted begin.
This is Problematic since it seems to also cut out the viewport display of the “fire” completely when the density is zero. Even Worse however is this also seems to carry over to Mantra where it doesn't render anything if that density grid has no voxel count.
It can be remedied by literally dropping a volume wrangle after the vdbConvert and setting “@density=@density;”
this magically pops the density voxel count back up to what it had incoming from the original volumes out of pyro. from the apparent empty voxel size —> @density (0,0,0).
I assume the vdbConvert is looking at all empty 0 value voxels and just “cleaning up” however, when it does this it seems to clip all the other channels too. this is even more apparent when you have only a little density in a small area and your fire is huge.. it clips the fire in viewport and in mantra down to the small density grid size.
this seems like a bug ?
can anyone shed some light on this..
thanks in advance
-johnc
