splines in space

the basic marker set i'm using has 61 (passive) markers ^{[marker set front & back]} tracked using a Motion Analysis system.

The image below shows the paths (coloured lines) of the markers and a htr skeleton^[Lulewicz] derived from SIMM (Software for Interactive Musculoskeletal Modeling)^{[Neuromuscular Biomechanics Lab]} solving within the Motion Analysis software^[ma-simm].

The movement is a torso spiral with an extended right arm. An eight camera setup was used to tracked the motion at 200 Hz, marker noise was cleaned using a 20 Hz Butterworth filter^[Wikipedia].