Ray is an optical simulation system, developed jointly by Wolf-Dieter Heker (ray tracing) and Robert Hemingway (user interface). The example scenario shows a human eye. On the left there is a light source "flood". You can move the whole light source by moving point lf0'flood. Change the direction by moving the small unlabelled point right to lf0'flood. Click on cp0'flood to toggle between the characteristics of "flood": green means parallel, blue divergent, black convergent and red is free form. Above "flood", there is a yellow point labeled "flood rays". You can move this slider to change the number of rays.
Please change the flood back to parallel state (green).
Right to the light source, you can see a lens labeled "glasses". Click on the green point labeled "ch0'glasses" and the glasses will disappear; the point changes to red. The poor man has lost his glasses and you can see that the light is no more focused on the retina.
Now have a look at the iris, represented by two black segments. Move the lower end of the upper segment to close the iris (the lower segment will automatically keep the diaphragm symmetric). You will realize that blinking the eyes helps to get a sharp image in case you have lost your glasses.
Restore the iris to its original state and click again on "ch0'glasses"; the glasses will come back.
Now move the blue point below "ch0'glasses". This is a slider that lets you control the refractive index of the glasses. Click on the pink points near the center of the glasses to change the shape of the lens. Move the point "n0'glasses" to move the complete lens. Press the button "drag mode" on the upper right. Move "n0'glasses" to move the edge of the lens only. The lens will keep its symmetry to the axis defined by the black points.
Now click on "n0'glasses" to change the surface properties of the lens. Click and move to experiment.
Click on button "Controls" and then on "Clear All". Now move MakePt to the left of the canvas. Click on buttons "Sources", "Laser", Lenses", "Para/Flat", "Others", "Prism", "Mirrors", "Mirror" and have fun.
