Using 3D animation to visualize complex skeletal movements during sloth locomotion
John A. Nyakatura 1, Jonas Lauströer 2
1 Institut für Spezielle Zoologie und Evolutionsbiologie mit Phyletischem Museum, Friedrich-Schiller-Universität Jena; 2 3D Illustration und Animation, Hamburg
Movements of mammalian skeletal elements are obscured by fur and tissue and cannot directly be investigated. The important role of proximal segments regarding the contribution to propulsion was demonstrated with cineradiography. Complex three dimensional movements, for example of the scapula, are difficult to comprehend even with the help of simultaneous multi perspective cineradiographic recordings - especially for people that are not used to cineradiography. To improve visualization of such movements we present a method using 3D animation software based on simultaneous digital high-speed cineradiographic recordings from the lateral and dorso-ventral perspective and CT-based reconstruction of all bony elements. Visualization of sloth locomotion was undertaken in the following steps: 1) A de-articulated skeleton was CT-scanned. 2) Surfaces wer rendered for bones and exported. 3) Skeletal elements were imported into 3D software and the skeleton was virtually re-assembled. 4) Virtual joints were created and attached to the reconstructed skeleton. 5) The virtual jointed skeleton was then animated frame by frame according to the cineradiographic recordings which were uploaded as image-sequence planes. The animation was finally rendered and exported as video file. The rather conservative kinematic patterns of sloth locomotion can thus be visualized. This method is not restricted to mammalian locomotion, but can be used to demonstrate many aspects of vertebrate skeletal movements.