This might apply to molds but here is my problem. If I want to support a complex part in an area that has many different surfaces how can I do this. If I sketch a area under the surface and try to extrude up to it I can't pick the body and if I pick a surface I can only get one. I would like to extrude to surface and be able to pick more than one surface. Another option might be if I could do a subtract from one to the other but I'm not sure how if possible to do this.