In the sculpt -> retopology workflow, it is very convenient to use textures with height information to add details "creatively", meaning you can drag them around and place them where it looks best:
The issue is, that you have to apply a multiresolution modifier to the entire mesh, that you'd like to use this method on. This is not feasible in many cases, for example I'd like to use this method on a sculpt of a figure I already sculpted:
If I'd apply a multiresolution modifier, I'd quickly need more ram than Google has in their servers.
If I were to just use the brush on the existing mesh, the resolution would be too low and it would get really laggy:
Is there a way to use this creative, responsive method, with the visual feedback on a high-poly mesh? In an ideal world, only the extra geometry needed for the brush to look good would be added, which is neglible. I know an alternative is the boolean modifier, however you can't really use it with alphas, you have to go out of sculpt mode and it is equally slow.