Use the ctrl key pressed and mark the region, or if you want to mark inside the mesh, use the ctrl and the rectangle mask selection format. Do not use a mask with the Move brush, it will not work effectively.
About
General questions regarding all MeshMolder-related topics.
Use the ctrl key pressed and mark the region, or if you want to mark inside the mesh, use the ctrl and the rectangle mask selection format. Do not use a mask with the Move brush, it will not work effectively.