We are investigating a computational method to render in real-time the
3-D viscoelastic properties of tissues, so that a user may experience a
mechanical interaction with these tissues, provided that a haptic device
of sufficient fidelity is available. Drastic computational reduction is
accomplished by implementing a multi-layer finite element mesh. The top
layer, or parent, consists of a coarse mesh of the entire body; child meshes
represent sub-regions of the coarse mesh, but have a much finer resolution.
By using equivalent impedances to relate the two meshes, it is possible
to decouple the coarse and fine regions; this enables the system to not
only have different resolutions in different regions, but also allows the
parent and child meshes to be updated at different frequencies. The multi-layer
mesh also addresses numerical integration issues.