I wanted to make sure I am doing this right, I have a simple box, vdb to polygons, fog vdb density, that I am putting into a vdbsmooth sdf for a "mask". It "works" but I can see a line at the front of the mask. No matter what I do, I cannot get a nice feathered mask. I have played with the boxes interior band voxels and exterior and they do not seem to make a real difference. Any help would be greatly appreciated, thanks.

I just slapped on a smooth with filter quality set to 1 and strength 100 over top and I guess it works alright now. I used a falloff object to drive a mask on the leading edge, then used that mask to drive a blend shape so just that area was smoothed.