Printed in Great Britain. GLOBULAR DYNAMICS A CONNECTED PARTICLE SYSTEM FOR ANIMATING VISCO.pdf

Comput. Graphics Vol. 13, No. 3, pp. 305-309, 1989 Printed in Great Britain. 0097-8493/89 $3.00 + .00 ? 1989 Pergamon Press plc Computer Graphics in Canada GLOBULAR DYNAMICS: A CONNECTED PARTICLE SYSTEM FOR ANIMATING VISCOUS FLUIDS GAVIN MILLER Apple Computer, Inc., The Advanced Technology Group, 20525 Mariani Ave., M5:22Y, Cupertino, CA 95014 and ANDREW PEARCE Alias Research, Inc., 500-110 Richmond St., E., Toronto, Ontario, Canada M5C 1P1 Abstract— Connected particle systems can depict many objects difficult to model in any other fashion. We present a method for animating viscous fluids by simulating the forces of such particles interacting with each other. This method allows for collision detection between the particles and obstacles, both stationary and mobile, and it allows solid objects to break and melt. An approximate method for covering the particles with an isosurface for efficient rendering is also presented. 1. INTRODUCTION We are interested in modeling materials such as lava, mud, slime, oil and salad dressing, as well as breakable, meltable solids. Existing techniques which could be considered include bicubic patches[1] and blobby molecules[2]. However, problems arise with both methods. It is difficult to model amorphous shapes with bicubic patches since they cannot be broken into arbitrary pieces. Blobby molecules do model amorphous shapes but two problems arise: 1. Blobs need a dynamic model for animation which includes collision detection and blob to blob interaction. 2. We wish, to render many blobs with limited memory, using existing fast rendering hardware to produce animations quickly and inexpensively. Particle systems[3] provide a dynamic model for the trajectories and collisions but do not take into account particle interaction. Soft objects[4] apply some motion control to blobs but ignore collisions between blobs. Recently, elastically deformable models[5] were proposed which provide a technique for computing the shape changes of continuous