Using a weightmap applied to geometry for sculpt masking

been checking with the masking options in blender when I am in sculpt mode, but I can´t find a way to fill an object with mask, it seems to just make a full fill masking.

And painting the mask in is not really an option, I really need a way to convert a weight painted, or a weight attribute when importing from other software to be just converted to a mask in sculpting mode, just as we can convert a weightmap to vertex paint sort of.

The reason for this is that I have a large set of various procedural texture I can apply as a weightmap to an object in other software, and the weightmap is intact when export from that and to blender when I import it, so I just want to convert that to a mask I then can extract a mesh from.

Any ideas, tips?

Ah…think I solved it.
you can just use the vertex paint, so…with an imported object with a weight paint, you can in vertex paint convert from weight paint, then in sculpt mode use the mask by color.

so basicly…