I design folding knives.  I'm trying to keep parts that are "Blocked" from passing other parts in while I rotate them.  I know setting up Entity Snap would work and I've tried for hours to get it to work but to no avail.  I can attach my dxf if needed but a quick step by step or a resource for instructions would be great.  I've already scoured the PDF manual and it just doesnt help.

Thanks in advance

Darrin