How do I create a part model "machined.prt" using a portion (25 mm of 250 mm bar)of bar-stock.prt Model (Extruded bar) as material. I want the Stock model drive the machined part profile. I also need to report in structure

How do I create a part model "machined.prt" using a portion (25 mm of 250 mm bar)of bar-stock.prt Model (Extruded bar) as material. I want the Stock model drive the machined part profile. I also need to report in structure