Research And Improvement Of Cloth Tearing And Collision Detection Algorithm With Fluid

In computer graphics,the interaction between cloth and fluid is very general,and it is involved in the fields of film,television entertainment,medical simulation and so on.The motion process of cloth and fluid has different physical characteristics,the interaction between them increases the complexity of each other’s movements,among the more common problems are fluid penetration through the cloth,the penetration of the cloth itself and the tearing of the cloth.In some applications,the interaction between cloth and fluid not only emphasizes accuracy,but also requires real-time.Therefore,to meet the above requirements,it is necessary to modify the traditional collision detection method or improve the calculation efficiency.Firstly,combining the mass spring model and the position-based dynamic method to model the cloth,cancel the internal force of the spring between the particles,introduce the tensile constraint and the bending constraint to control the particle,the positions and velocities of colliding particles were modified during the collision.The verlet integral was optimized by reducing the simulation accuracy to simulate the phenomenon of cloth and fluid collision more rapidly.Secondly,the collision between the cloth and the fluid is detected by the dilated continuous collision detection method,the collision response between the cloth and fluid is treated by the improvement contact force based on the punishment,and increase the interaction factor to record the first contact time between the cloth and the fluid.Then within the time slice,the k-DOPs inflation bounding volume hierarchy is used to detect the self-collision of the cloth,and the constraint is introduced to process the self-collision response.Thirdly,the tearing effect is increased,the basic tearing method is optimized,the tearing threshold is set for the particle of the cloth,so the tearing trajectory of the particle is predicted,and the tearing damping is obtained by calculating the tearing threshold,which is used to eliminate the cloth shaking phenomenon in the tearing process.After the collision of the cloth and fluid,the force generated by the cloth particle and the fluid particle will be superimposed,and the system will update the position and velocity of the cloth particle and the fluid particle according to the numerical calculation of constraint dynamics and collision force,so as to realize the simulation of the movement process of the cloth and the fluid.Finally,in the hardware system for the Intel i7-4790 CPU and graphics card for the NVIDIA GeForce GTX 750 Ti simulation experiments,using the Unity physics engine combined with the c# language,developed and completed the experiment of collision detection when the cloth tears and interacts with the fluid.