Design And Implementation Of Physics Engine For Rigid Body And Cloth Simulation In3D Clothing Fitting System

With the continuous development of3D computer graphics, more and more peoplestart to use computers to simulate the real world. On this basis, a large number ofrelated areas and applications such as virtual reality, three-dimensional dynamicsimulation,3D animation, computer film special effects,3D games have emerged. Andphysical engine is a key tool for these applications, which can decide the core quality ofthese applications.This paper studies and summarizes the present situation of3D fitting system athome and abroad, analyzes the existing problems in the current system, determines theresearch direction and the research content of this paper, namely designing andimplementing the physics engine of3D fitting system, carrying out the simulation ofrigid body and simple cloth in the basis of depth study and discussion to the keytechnology of the physics engine.In the basis of analysis of system function and performance requirements, thefunction design, process design and detailed design of the system are carried out. Thephysics engine includes four functions: file processing function of the model, the rigidbody simulation function, cloth simulation function,3D display function. Among them,the rigid body simulation function needs model on various entity models which areentered into the system, real-time solve the motion equations, process the collisions ofrigid body, simulate rigid body physics movement; the cloth simulation functionrealizes some simple fabric, such as curtains, towels and so on. Its state of rest andstress state are both required simulated; when the rigid body simulation function andcloth simulation function complete the operation, the movement of objects need to bedisplayed with3D; in addition, the rigid model system needs comes from the externalinput, so the file processing function needs to be scheduled into the system accordancewith the file format of3D model, simulation and pretreatment of some models forengine, also need some auxiliary function such as reading and writing.Through the test on each module function of the system, and analysis of the testdata, the physics engine implemented in this paper is tested to achieves the expectedgoal. It can be seen according to the test data of each function, both in function andperformance, each function module is fundamental to the demand, although the system still has some problems, but these problems basically does not affect the normal use, thesystem and test data, also provide a detailed reference data for the future of the systemto maintain and upgrade.This paper mainly realizes the design and implementation of rigid body and clothsimulation in the3D fitting system. In rigid body simulation, this paper designs andrealizes an efficient and viable rigid body collision detection algorithm. Using Octree todivide the rigid models and using OBB algorithm to detect the intersection between twocells of the Octree. This method precisely handles the collision between the rigid bodies,at the same time, guarantees the real-time simulation. In cloth simulation, this paperadds the thought of Simple Linear Bending Stiffness in Particle Systems, which furtherenhances the reality of cloth simulation.