The One Rotation That Should Remain
How preserving intentional rotational degrees of freedom prevents over-constraining concentric fastener stacks and spherical linkages.
Kinematic Foundations
Degrees of Freedom & Permitted Motion
Every unconstrained component carries six degrees of freedom. These notes explain how to decide which translations and rotations the design actually needs to keep.
Reading Allowed Motion
A good constraint preserves the motion that the design actually needs. The guides below show how to count remaining freedoms and verify they match the intended mechanism.
The Difference Between Fixed and Fully Defined
Why arbitrary fixed grounding masks geometric dependencies that true origin-aligned mates systematically reveal.
When a Mate Removes Too Much Freedom
Identifying over-defined kinematic pairs where parallel and coincident mates inadvertently lock required compliant movements.
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