TITLE: Crab Angel Wing NAME: Bill Newcum COUNTRY: USA EMAIL: bill@astconsulting.com WEBPAGE: none TOPIC: Internet Ray Tracing Competition, Stills COPYRIGHT: I SUBMIT TO THE STANDARD RAYTRACING COMPETITION COPYRIGHT. JPGFILE: crabsim.jpg RENDERER USED: POV-Ray for Windows v3.5 TOOLS USED: Java simulation program RENDERER TIME: 52 minutes HARDWARE USED: WinBook J4 laptop with 2 GHz Pentium IV and 512 Mb memory IMAGE DESCRIPTION: This picture is the result of a simulation of the motion of a blue crab's front left leg. My daughter was writing a paper on the defense zone of the blue crab and had to measure actual legs from crabs. I suggested that she also measure the angles of each joint, and offered to write a simulation program that would create surfaces that represent the movement of the tip of the crab leg. The intermediate surfaces are artifacts of the simulation. A crab can move its leg anywhere between the inner and outer surfaces. The simulation showe that a crab cannot defend its back. This image may not be the most attractive in your collection, but it could fit into the "most unusual" category. It illustrates a scientific use for rendering programs. DESCRIPTION OF HOW THIS IMAGE WAS CREATED: Crab legs have 5 leg sections. Each leg section has a hinged joint. The Java simulation program builds a 3D model of a leg one section at a time, and rotates each joint a few degrees for each iteration of the simulation. The result of a single interation is a small patch, or mesh. After thousands of iterations that represent the full range of motion in each joint, the combined meshes yielded a the set of surfaces shown in the image. A 2.3 Mb zip file of the POV-Ray input model is available. The POV-Ray model includes multiple camera and light source combinations that allow the image to be viewed from different angles.