Unfortunately the modifier has to be baked(collapsed) Having unwrap as a mode in Max rather than a modifier is something the community has been crying out for for some time. there's a Tweak UVs mode in the modifier, but you can't directly manipulate the geo.
Coming from Maya to Max, one thing that I miss is the ability to select edges and verts in my unwrap and be able to have those selected on my mesh in a way that allows me to manipulate them. Really handy to have for alpha work and the like. Does anyone know: is this is achievable in 3ds Max? Since it's a modifier stack and…