Figure 1.

Comparison of fixed and flexible axis rotation. (A) Rotating the sketched shape inside the white tubular cavity creates severe artifacts when a conventional fixed rotation axis (dashed) is used. More realistically, the shape would revolve like a flexible pipe-cleaner (dotted) inside the bearing (gray). (B) Fixed rotation around an axis v with a pivot point specified by the vector u. (C) Subdividing the rotating fragment into slabs with separate rotation axes (↑) and pivot points (•) for each slab allows for the required flexibility. The distance between two slabs with indices n and n + 1 is Δx.