Rez a prim, change to sculpted, use the "plate" sculpt map from the library and the prim disappears. Friends on firestorm can see it, I cannot. I can take it to inventory if I"m lucky usually I cannot. I must relog to see the sculpt. I teach building classes so to avoid this downfall, I give them the sculpt. Sometimes it appears, sometimes it does not. Students have to relog to see what they are building. This happens on any sim, any time of day. I have more trouble with the plate sculpt than sculpts I make, but really either way it makes sculpts nearly impossible.