I want to know what the difference is between a reference part and a reference model. When I create a mfg from scratch I get the option of assembling a ref model,workpiece,Mfg assembly or general assembly. The other day I created a mfg using the save a copy command because 2 parts were similar except for minor changes. I renamed everything using the new part name. Now when I try to assemble my model my only option is a ref part. It seems to work fine but the model is at the bottom of the model tree and I can't move it ahead of the toolpaths. Also all of my toolpaths are associated with the workpiece. I also lost the ability to create a new workpiece. This hasn't happened before so I wondered if anyone else has had this problem.