> There are free raytracing packages available that allow you to > describe a 3-dimensional object and render an image of it with > light sources placed at will. Has anybody used these to simulate > sundials? Seems like it should work.
Yes, I tried it with POVRAY. I defined a stone and a long cylinder as the shadow caster in this ray tracing software. The necessary POV-files were generated by a program calculating suns azimuth and elevation to put the light source in the correct direction. The small movie I generated shows the figure 8 line "painted" by the shadow through one year for the same mean time each day. I think this is of great educational interest but so far I had no time to make more movies (including the numbers, lines and so on on a sundial). - Daniel Roth
