An Octree Model Generation Algorithm For Flexible Body Cutting Simulation

In recent years,with the development of programmable Graphics Processing Unit and computer graphics,medical simulation played an increasingly important role in the medical field.Surgical simulation in medical simulation is that realistically simulate the organ model being deformed and even cut under the force of the surgical instrument.In order to realize the organ,the so-called ‘Deformable Object',reality of deforming and cutting.model need to be voxelized,so that it can be used to simulate by mathematical calculation.Because of organ models are mostly non-manifold or self-intersecting triangular geometry.Therefore,take advantage of distance field to voxelize non-manifold geometry is the key to solve the problem that it is difficult to voxelize human organ model.As many triangles used for cutting simulation are unoriented,non-manifold or selfintersecting,which leads to ambiguity in mathematical terms.A distance field is a representation where,at each point within the field,we know the distance from that point to the closest point on any object within the domain.In addition to distance,other properties may be derived from the distance field,such as the direction to the surface,and when the distance field is signed,we may also determine if the point is internal or external to objects within the domain.The distance field has been found to be a useful construction within the areas of computer vision,physics,and computer graphics.The algorithm of this paper firstly defines the offset surface of the unsigned distance field that extracts from any triangular geometry then automatically deletes internal components,after that the sign distance field is calculated from the offset surface,and the threshold value is worth to reconstruct the surface,which is very close to the original mode.At last,the reconstructed surface is voxelized.Also we can produce voxelized modal which is suitable for cutting simulation.This algorithm can accurately produce the body-element model of complex mesh,which contains both self-intersection and non-manifold geometry,and the cost of time and memory is low and the effect is better.