i have one 3d model in .cat format. I want to make changes in basic 2d geometry to make a new model. how to convert a 3d model into 2d geometry ?
To convert 3d model into 2d geometry - you should use Drafting. Here is a link https://grabcad.com/questions/tutorial-how-to-use-drafting-workbench-in-catia-v5?utm_campaign=engagement-recommend-questions&utm_content=question-title&utm_medium=email&utm_source=user-email
If you want to "make changes" you should to make corrections in building tree. If model was build in catia, if imported - reverse enginering only way