bug#47463: Blender: Voxel remesher failed to create mesh

[Ekaitz Zarraga]

Hi,

I found an issue with blender. Our packaged version it's not able to run the
Voxel Remesher, I think because OpenVBD[^1] is not included in our package.

Every time I use the Voxel Remesh tool it says:
"Voxel remesher failed to create mesh"

But the Quadriflow remesher works fine.

I searched a little bit in the code and I found the following:


Here is where the error message appears (object_remesh.c:147):

``` c
  new_mesh = BKE_mesh_remesh_voxel_to_mesh_nomain(
      mesh, mesh->remesh_voxel_size, mesh->remesh_voxel_adaptivity, isovalue);

  if (!new_mesh) {
    BKE_report(op->reports, RPT_ERROR, "Voxel remesher failed to create mesh");
    return OPERATOR_CANCELLED;
  }
```

So it means the `new_mesh` is not created. Checking the definition of the
`BKE_mesh_remesh_voxel_to_mesh_nomain` function we get this
(mesh_remesh_voxel.c:296):


``` c
Mesh *BKE_mesh_remesh_voxel_to_mesh_nomain(Mesh *mesh,
                                           float voxel_size,
                                           float adaptivity,
                                           float isovalue)
{
  Mesh *new_mesh = NULL;
#ifdef WITH_OPENVDB
  struct OpenVDBLevelSet *level_set;
  struct OpenVDBTransform *xform = OpenVDBTransform_create();
  OpenVDBTransform_create_linear_transform(xform, (double)voxel_size);
  level_set = BKE_mesh_remesh_voxel_ovdb_mesh_to_level_set_create(mesh, xform);
  new_mesh = BKE_mesh_remesh_voxel_ovdb_volume_to_mesh_nomain(
      level_set, (double)isovalue, (double)adaptivity, false);
  OpenVDBLevelSet_free(level_set);
  OpenVDBTransform_free(xform);
#else
  UNUSED_VARS(mesh, voxel_size, adaptivity, isovalue);
#endif
  return new_mesh;
}
```

I also checked blender package and I doesn't look like it includes OpenVDB, so
this makes sense.

As this is a powerful tool and enables much better workflows for sculpting I
think we should add it.

I'll try to add it myself, if you are ok with that.

Best,

Ekaitz


[^1]: https://www.openvdb.org/