Real-Time Collision-Aware Musculoskeletal Model for Virtual Human Animation

Abstract

This MSc project focused on combining a biomechanical musculoskeletal model with a high poly musculotendon model for the lower human body. A low-poly cylinder-based musculotendon unit is constructed that segments muscle and tendon into separate compartments. The shape of high poly meshes is approximated through ray-triangle intersection tests. Point samples are then used to move action lines of the biomechanical model within the high poly model. Once inside, ray-triangle intersection tests are carried out again to get a more accurate approximation of the surface of the high poly model. The method was developed in order to be invariant to spatial and polygonal configurations. Results with 48 musculotendons for the lower body show a drop of approximately 84% with respect to the number of vertices when compared to the high poly model.

The project also considered real-time as a criterion and introduced a scalar for the geometrical model allowing each cylinder to be scaled in both longitudinal and latitudinal directions. The amount of information could therefore be increased or decreased to retain real-time performance on faster or slower computer hardware. An experiment with 10 muscles resulted in a runtime of 164Hz on average having a total of 25 constraints. Finally, a custom collision constraint between musculotendons was introduced, coupled with an area preservation technique used during deformation, which takes advantage of the cylindrical construction of the real-time model.