Real-Time Plastic Deformation of Car Bodyworks

Abstract

Realism in video games is furthered each year. Particularly in racing and driving games, visual realism in the deformation of cars play a larger and larger role for the immersion in a virtual world. With the improvements of modern hardware, a new physically based simulation approach for the deformation of object has emerged. In this thesis a prototype is developed that aims to implement such a deformation system for car bodyworks. One of the many challenges is to generate visually appealing deformations, while remaining within the constraints of the real-time context. There is a variety of deformation techniques in the body of research. At their core, most work similarly. The deformable object is discretized into smaller units, so called particles. These particles are subject to the forces of the virtual environment and thus adjust the superordinate deformable object. The method of choice for this thesis’ prototype is position-based deformation, as it has many advantages for a real-time context. In position-based deformation, the particles are interconnect via constraints, which adjust their positions in relation to one-another. These constraints are solved each frame by an iterative Gauss-Seidel solver. It was integrated into a deformation module which is used by the physics engine Unity to compute deformation results. This configuration proved successful as it makes use of the strengths of both a third-party physics engine and a more performant module for time-critical algorithms. The prototype was developed based on an agile software development philosophy and was continuously improved and optimized. The prototype was analyzed regarding the computational performance and the visual results. Depending on its configuration, the system computes deformations within 5-150 ms per frame on an Intel i5-8500 CPU. The results suggest that the performance can be enhanced by using a more sophisticated solver method and by utilizing the GPU. The visual results are promising, but suggest that properties must be distributed thought an object in a non-uniform manner. This can generate a more visually interesting result, as it mimics the existence of vehicle parts that are varying in their structural rigidity.