Is it possible to add voxels to a sim in Houdini? A quick test and the fields reset when adding voxels.

you can use Gas Resize Field or Gas Resize Fluid for that

Works perfectly!

Do you know of any Gas Microsolvers to help with building a sparse solver? I need to remove fields outside of the density. I can roughly do it, memory is reduced by half, but the velocity fields get hammered and don't solve correctly anymore.

I think this is using VDB (sparse), take a look at that: http://www.orbolt.com/asset/953u6015t::pyrojunior
You cannot do it in DOPs though afaik.

Skybar
You cannot do it in DOPs though afaik.

Oh I was under the impression that losseless compression happens on contiguous areas. Poor looking lossy compression can happen with the Tolerance value on Scalar/VectorFields. VDB should just also have very fast access to voxels as well as being sparse.

fuos

Skybar
You cannot do it in DOPs though afaik.

Oh I was under the impression that losseless compression happens on contiguous areas. Poor looking lossy compression can happen with the Tolerance value on Scalar/VectorFields. VDB should just also have very fast access to voxels as well as being sparse.

No idea about that, but I meant sparse as in terms of VDBs. Compression might be possible though? Dont know

Yeah - I can't really find a good definition to differentiate Sparse and RLE style compression and it looks like the Scalar/Vector Field Dops convert VDBs to normal Houdini fields.

Anyways, I guess the next question is what is the difference between an ad hoc field, like Gas Field Match makes, and a proper field that SOP Scalar Field makes. Is it that we can't extract an ad hoc filed back to sops?