The POVRAY topics:
OPTICAL DESIGN AND MODELING WITHNovember 2005
POVRAY AND ZEMAX
( Rev. Jan 2006, June 22 2008, August 2008))
I was horrified yesterday (21 June 2008 ) when I attempted to play the movies on my recent replacement PC ( Windows XP), Media Player sent an error message to the effect that it could not open the files ( avi and m1v). Later that day, I went to a Vista PC, and found that that PC would play them OK. Today, (22 June) I installed k1codec395f.exe and found that they did run, using the very much older version of Media Player.
Although primarily of use for
more visually attractive images of optical systems, POVRAY has a number
of advantages in the visualisation of the primary and straylight images
created by real optical systems.
An essential capability to
POVRAY is the
conversion from the traditional optical prescription sequential
notation of 'Radius, Thickness, Index, Aperture, Aspheric Data' to the
co-ordinate notation of CSG objects. I've placed at this
four 'include' files which allow this conversion to be performed,
albeit manually. It would be highly desirable if someone
code that performed this conversion automatically - but I have found
that using a pre-programmed text in an include file even the most
complex system can
be converted to POVRAY notation.
recently ( December 2005 ) come across another optical design program
'OpTaliX' at www.optenso.de which
does indeed feature an ability to export traditional optical
design prescriptions in POVRAY format.
At least a rudimentary
familiarity with the POVRAY code, Version 3.6 is required.
installed on a PC, I'd expect that the zipped *.pov and *.inc files
Just to show to a traditional optical designer what is possible in POVRAY, this is a movie of a model of a 'brilliant' cut diamond.
If you're willing to wait a lot longer (for a 14MB file)
It shows POVRAY's ability to create virtual chromatic images in the diamond volume and real images on the table. Notice that the image is 'photorealistic' - no rays are present. But POVRAY cannot create optical systems to meet a design aim. Its purpose is to provide a pleasing illusion of reality.And just to show to a POVRAY user, this is a ZEMAX raytrace lens design model of a highly stylised human eye. Notice that the geometry of the lens object and the paths of energy transport are shown as lines, or rays, on a 2-D representation of reality. Although the image is not 'photorealistic' this is the design representation which is an essential part of the optical system creation process.
In reality, the eye is rather more complex than this model. More detail on the lens itself, as it affects the treatment of cataract is shown here. http://www.crstoday.com/PDF%20Articles/0806/CRST0806_PR.pdf
And, if you're not squeamish, you might enjoy this movie of cataract surgery, in which the lens, clouded by age in my case, or excessive ultra-violet radiation in sunlight, typical in the tropics, is destroyed by ultrasound and replaced with a plastic equivalent. http://www.youtube.com/watch?v=poGJSFLmrnc
I have recently ( August 2008) had such surgery, very successfully, at the hands of Mr.Simon Horgan of Harley Street, London. His website http://www.iiiicare.com/profile.htm offers further information on the biology of the eye.
POVRAY is only of use for optical engineering assessment if it can be trusted to yield correct physical results. This page compares results from the two programs when assessing an apparently simple 'non-sequential-components' situation.
Many optical scenes are constructed by lens shaped objects. Go to this page for a full description of the objects via html files. These 'include' files are used to create the objects in the three scenes.
The first scene is a four element lens zooming laser projector system constructed from three of the lens components, with the ray paths visualised both by traditional raypath diagrams from ZEMAX and by scattering in a POVRAY 'media' atmosphere.
The second scene shows how a complex system with a zooming lens and an internal scanning mirror and a de-rotation prism can be animated.
The third scene shows a conversion of a Pro-Engineer CAD object to a POVRAY scene file using the SLP2POV conversion utility.
The technology of thermal infrared cameras has evolved over the last 65 years. This page shows some results of modeling how the performances have improved over the last 30 years.