An Efficient Method for Displaying Marks on Soft Grounds Created by Objects

Abstract

In recent years there has been a particular interest in secondary phenomena caused by the motion of objects in CG animation. Examples of such secondary phenomena include footprints that a character leaves in its wake, tire marks caused by cars and bicycles, and marks made by objects such as balls falling onto or being dragged along the ground. In this paper, we propose a deformation algorithm for the ground surface when it is in contact with objects. The deformation algorithm is divided into three steps: (1) The detection of the collision between the objects and the ground surface, (2) The compression and displacement of the ground material, (3) The erosion at a steep slope. The deformation of the ground surface is calculated in real time by using graphics hardware for collision detection, and by calculating the erosion step in limited regions on the surface of the ground.