A lot depends on WHAT you want to get from a training class. "NX for experienced designers" sounds like it is made for someone coming from a PTC or CATIA background and needs to adapt to NX. If this is what the class is intended for, then it makes sense that the instrutor would be teaching HOW to use the NX sketcher as the basis for the way NX works. While you may understand sketching, do you understand the way NX builds constraints in its sketcher? Most training classes are designed to teach the menus, not the principles of design.
Design Visionaires tends to lean their training towards design principles on top of the menus to get the most from the software.
If you are looking for better ways to inprove productivity with NX, then look at bringing in an application engineer for a week. Have them sit with your designers and observe how you do things today. Maybe 2-3 hours with each designer or senior designer, then allow the application engineer to hold a 1/2-1 day 'suggested improvement' session(s). Document your company's Best Practices in doing certain functions within the software. Use templates for your start parts for uniformity. Know how to use expresssions and relations to drive your models.
Training is an investment, not an expense.
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