Simple classification technique for 3D highly heterogeneous domains and its application in defibrillation modeling

An efficient method is developed and implemented for classification of three dimensional objects with different material properties and highly irregular boundaries. The ray “tube” tracing technique proposed here was developed as a part of a software for automatic generation of unstructured three dimensional finite element grids. It operates on volumes tessellated in tetrahedral elements and region boundaries represented by surface triangles. This method is object independent and appropriate for convex and concave regions, with many depth levels. It is simple and gives a significant speedup (up to 15 times) compared to the traditional ray tracing by confining the search and the computationally expensive procedures to about 7% of all surface triangles for a given region. The “tube” construction, is based on the distance between the centroid of the surface primitives and the ray. Complex structures with different conductivity properties are typical in large-scale finite element modeling in electrocardiology (including the torso, skeletal muscle, lungs, epicardium, heart with major blood vessels, different electrode configurations, etc.). The classification algorithm was successfully applied to a variety of problems calculating defibrillation induced potential fields using physiologically realistic geometries