Using the POV raytracer to illustrate physics and math concepts
The POV raytracer is a free program that can be used to
build virtual computer models that are then photographed using a virtual camera. The computer uses the known
laws of optics, together with some clever computer shortcuts, to produce photorealistic images. The POV
raytracer can be used to make purely artistic images, but it can also be used to help visualize complicated
physical and mathematical concepts. It can also be used to teach students about the interaction of light and matter.
I should point out that POV has a very steep learning curve. You should not expect to sit down and produce high
quality three-dimensional images within a matter of minutes. However, once you have mastered POV, it is possible to
create some really remarkable images within a short amount of time.
Before I discuss how to use POV for scientific purposes, I should emphasize that it can be used purely for creative art.
One of my favorite POV artists is Gilles Tran
who has created some remarkable works of art, including the following:
Note that Gilles Tran often provides free POV
models so you can experiment with his works of art and build your own.
Now for some more scientific references.
The video below shows a wave traveling through the blue medium towards the green medium. The incident wavefronts can be seen
in the form of the shadows they cast on the surface of the blue medium. The colored balls initially move parallel to the
incident wave. You can think of them as the heads of surfers riding the wave. When they encounter the boundary at the green
medium, the colored balls are reflected and travel parallel to the reflected wave. The wave velocity in the green medium
is significantly higher than the velocity in the blue medium, and the angle of incidence is sufficiently large to prevent the
waves from propagating into the green medium. This phenomenon is known as total internal reflection and is usually depicted using
ray optics without any light entering the fast (green) medium. Nonetheless, there is a disturbance present in the green medium
that decays exponentially with distance. This disturbance is known as an evanescent wave. The incident and reflected waves give
rise to an interference pattern with maxima that move parallel to the surface of the blue-green boundary. If the blue medium
is a piece of photographic film, then the maxima create a series of lines within the film. When developed, these lines form a
Paul Nylander has created some wonderful physics images
including this image, which appeared on the cover of the September 2009 issue of Physics Today and inspired my 3D dipole image.