You may suppress the output to the console of the Debug, Fatal, Render, Statistic or Warning text streams. For example the Statistic_Console=off option or the -GS switch can turn off the Statistic stream. Using on or +GS you may turn it on again. You may also turn all five of these streams on or off at once using the All_Console option or +GA switch.

Note that these options take effect immediately when specified. Obviously any Error or Warning messages that might occur before the option is read are not be affected.

You may direct a copy of the text streams to a text file for the Debug, Fatal, Render, Statistic or Warning text streams. For example the Statistic_File=s option or the +GSs switch. If the string s is true or any of the other valid true strings then that stream is redirected to a file with a default name. Valid true values are true, yes, on or 1. If the value is false the direction to a text file is turned off. Valid false values are false, no, off or 0. Any other string specified turns on file output and the string is interpreted as the output file name.

Similarly you may specify such a true, false or file name string after a switch such as +GSfile. You may also direct all five streams to the same file using the All_File option or +GA switch. You may not specify the same file for two or more streams because POV-Ray will fail when it tries to open or close the same file twice.

Note that these options take effect immediately when specified. Obviously any Error or Warning messages that might occur before the option is read will not be affected.

Graphical interface versions of POV-Ray such as Mac or Windows have extensive online help. Other versions of POV-Ray have only a few quick-reference help screens. The +? switch, optionally followed by a single digit from 0 to 8, will display these help screens to the Banner text stream. After displaying the help screens, POV-Ray terminates. Because some operating systems do not permit a question mark as a command line switch you may also use the +H switch. Note however that this switch is also used to specify the height of the image in pixels. Therefore the +H switch is only interpreted as a help switch if it is the only switch on the command line and if the value after the switch is less than or equal to 8.

The Quality=n option or +Qn switch allows you to specify the image rendering quality. You may choose to lower the quality for test rendering and raise it for final renders. The quality adjustments are made by eliminating some of the calculations that are normally performed. For example settings below 4 do not render shadows. Settings below 8 do not use reflection or refraction. The values correspond to the following quality levels:

Radiosity is an additional calculation which computes diffuse inter-reflection. It is an extremely slow calculation that is somewhat experimental. The parameters which control how radiosity calculations are performed are specified in the radiosity section of the global_settings statement. See section "Radiosity" for further details.

POV-Ray uses a variety of spatial sub-division systems to speed up ray-object intersection tests. The primary system uses a hierarchy of nested bounding boxes. This system compartmentalizes all finite objects in a scene into invisible rectangular boxes that are arranged in a tree-like hierarchy. Before testing the objects within the bounding boxes the tree is descended and only those objects are tested whose bounds are hit by a ray. This can greatly improve rendering speed. However for scenes with only a few objects the overhead of using a bounding system is not worth the effort. The Bounding=off option or -MB switch allows you to force bounding off. The default value is on.

The Bounding_Threshold=n or +MBn switch allows you to set the minimum number of objects necessary before bounding is used. The default is +MB25 which means that if your scene has fewer than 25 objects POV-Ray will automatically turn bounding off because the overhead isn't worth it. Generally it's a good idea to use a much lower threshold like +MB5.

Additionally POV-Ray uses systems known as vista buffers and light buffers to further speed things up. These systems only work when bounding is on and when there are a sufficient number of objects to meet the bounding threshold. The vista buffer is created by projecting the bounding box hierarchy onto the screen and determining the rectangular areas that are covered by each of the elements in the hierarchy. Only those objects whose rectangles enclose a given pixel are tested by the primary viewing ray. The vista buffer can only be used with perspective and orthographic cameras because they rely on a fixed viewpoint and a reasonable projection (i. e. straight lines have to stay straight lines after the projection).

The light buffer is created by enclosing each light source in an imaginary box and projecting the bounding box hierarchy onto each of its six sides. Since this relies on a fixed light source, light buffers will not be used for area lights.

Reflected and transmitted rays do not take advantage of the light and vista buffer.

The default settings are Vista_Buffer=on or +UV and Light_Buffer=on or +UL. The option to turn these features off is available to demonstrate their usefulness and as protection against unforeseen bugs which might exist in any of these bounding systems.

In general, any finite object and many types of CSG of finite objects will properly respond to this bounding system. In addition blobs and meshes use an additional internal bounding system. These systems are not affected by the above switch. They can be switched off using the appropriate syntax in the scene file (see "Blob" and "Mesh" for details). Text objects are split into individual letters that are bounded using the bounding box hierarchy. Some CSG combinations of finite and infinite objects are also automatically bound. The end result is that you will rarely need to add manual bounding objects as was necessary in earlier versions of POV-Ray unless you use many infinite objects.