Dialog Box - called from: File menu
POV-Ray is a program which draws a 3D image pixel-by-pixel, calculating all possible light-ray paths. It allows for much more elaborate lighting effects than the OpenGL or Direct3D software used in the 3D Drawing Modes in ATOMS. Some obvious effects are shadows and refraction but there are many possibilities. Backgrounds and other objects may be added as well. The files are text (ASCII) and may be edited.
Since the calculation is much more elaborate than that done by OpenGL, this is not a method that can be used for real-time display on the screen - POV-Ray images may take many minutes to complete.
The POV-Ray package, with instructions, samples, etc., may be obtained from www.povray.org.
While adding shadows to ball-and-stick or space-filling structure drawings may make them more "realistic", it also may tend to complicate things. Shadows are usually most beneficial to Cavities mode drawings of crystals. The default output from ATOMS has shadows, but this can be changed by adding the keyword "shadowless" after the color definition in the "light_source" definition near the beginning of the file.
Cavities - use spheres. Povray can show Cavities in its own way, using "constructive solid geometry". For this, it only needs the unit cell and the atoms. This makes for a smaller file and usually gives a much smoother appearance than the standard method used for cavities in ATOMS. If this box is not checked, the POV-ray rendering is exactly the same as that shown on screen.
Currently only one unit cell is shown, and crystal axes cannot be shown.