An I-DEAS CAD modeling developer works with the I-DEAS (Integrated Design and Engineering Analysis Software) to create, manipulate, and analyze design models. They use this software to create models from plans, modify existing designs, and perform simulations to test the functionality of these designs. The developer also uses the software's features for stress analysis, assembly modeling, and surface modeling. They communicate with engineers and designers to understand their requirements, troubleshoot issues, and ensure the final design is accurate and efficient. Their work is crucial in industries like automotive, aerospace, and manufacturing.