a non-hacky potential alternative to the invisprim hack llNoRenderVolume would make it so the face itself (regardless of transparency or alpha) plus anything (be it avatar, ground, particle, prim etc) inside the prim (but not behind or in the air inside it in case it is hollow) will not be rendered when viewed only thru that face, if a geometry overlaps, only the parts not inside will be visible, if there are transparent faces, the geometry would be visible thru those, but not thru the NoRenderVolume enabled faces llForceRender would make it so the face would be rendered ignoring any NoRenderVolume enabled faces in any prim, regardless of transparency or alpha edit: I don't think this should have any forced builtin sleeps