CAD is generally used to draw engineering drawings for production, while CDR is used for design, each with its own emphasis. In the glasses industry, these two softwares are generally used. Generally speaking, CDR draws good design drafts, selects some better designs from many design drafts, and directly makes samples or draws CAD engineering drawings to copy samples. Youku has a very detailed talk from the media. They have "video tutorial of CAD glasses drawing" and "video tutorial of CorelDRAW glasses design"