Real-time Bleeding Simulation Based on Moving Particle Semi-implicit Method

Computer graphics and virtual reality technologies have enables us to develop several medical systems such as preoperative planning, intra-operative navigation and surgical simulation systems. The training for each part of human bodies is available, which parts are head, eye, liver, bone and so on; however, real-time simulation of blood vessel deformation or bleeding is not available with the present systems. Blood vessels are one of the most important organs and placed everywhere in the body. On the other hand, there have been many researches for fluid simulation using hydrodynamics. They aim to achieve the precise result of fluid behavior with many particles and take huge calculation time for the simulation. As the result, it is too difficult to visualize the fluid simulation in real-time. Therefore, this paper describes the method of real-time bleeding simulation based on Moving Particle Semi-implicit (MPS) method. Fluid simulation is usually performed on Navier-Stokes equation. For incompressible fluid such as blood, constant density condition is necessary and it takes huge amount of time to calculate each particle position. This paper suggests a method to modify particle positions in order to satisfy constant density condition, and a fast method searching for neighborhood particles by using hash function, which maps 3 dimensional space to 1 dimensional memory array. This paper also suggests a smooth rendering method of blood surface, which is composed of many small spheres. As the result of some experiments, real-time visualization of bleeding for surgical simulators has become possible under the condition that the particle number is under 3,000. Keyword Computer Graphics, Virtual Reality, Hydrodynamics, Real-time simulation, Medical systems