Responsible suppliers treat CAD and drawings as confidential business information. Practical measures include access-controlled storage, least-privilege sharing inside the shop, and clear retention policies aligned to your NDA.
For RFQs, share the minimum geometry needed to quote—watermarked PDFs or simplified step files can reduce exposure during early discussions.
If you require a formal NDA before file transfer, send it early so procurement and engineering can align on signing authority and scope.