Degrees of freedom are easy to write on a whiteboard and hard to believe until a student watches a joint fail in CAD. In MET 201, students do not stop at a bracket. They model torso, neck, arms, and legs of a humanoid, then print parts and try to assemble them. Shoulder rotation that looked elegant on screen becomes a collision, a missing washer, or a servo that cannot reach the pose.
That is the point. Every extra joint costs motors, wiring, structure, control, and money. Students start to ask the industrial question: is this motion worth the complexity? The assignment is still CAD — mates, symmetry, wall thickness, holes, clearances — but the goal is a moving system, not a graded screenshot.
I use a physical reference robot in the lab so students can count axes on hardware, then find the same axes in their assemblies. The workbook that supports this approach is Humanoid Robot Design Fundamentals: A CAD-Based Approach to Degrees of Freedom. The MET 201 text is Designing for Materials, Manufacturing, and Assembly.
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