Ray Tracing a Swept Sphere
Leipelt Andreas, Mathematisches Seminar der Universität Hamburg Hamburg, Germany. E-mail address: leipelt@GEOMAT.math.uni-hamburg.de
This gem presents the basic algorithms required for ray tracing the swept surface (Hanrahan 1989) generated by sweeping a sphere along a path. These surfaces look like wound tubes with varying thickness, resembling plant stems or exhaust pipes.
Introduction
For ray tracing this interesting modeling primitive, one needs to solve the following problems:
• Compute the intersections with a ray.
• Determine the axis-aligned bounding box.
• Decide if a point is inside or not.
• Compute the surface normal at an intersection point.
In order to ease the computation, it is assumed ...
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