# The render options box : radiosity tab

## The radiosity tab.

Radiosity is an alternative, and more efficient, way to calculate participations of every object to ambient light. It is still considered as experimental but works quitte well, although it is a bit complex to use for newbies. If you don't know how radiosity works please consider refering to Povray documentation.

ADC bailout

You can specify an adc_bailout for radiosity rays. Use adc_bailout = 0.01 / brightest_ambient_object for good results. Default is 0.01.

Always sample

You can force POV-Ray to only use the data from the pretrace step and not gather any new samples during the final radiosity pass. This may reduce splotchiness. To do this, use always_sample off, by default it is on. It can also be usefully when reusing previously saved radiosity data.

Brightness

The brightness keyword specifies a float value that is the degree to which objects are brightened before being returned upwards to the rest of the system. The default value is 1.0. In cases where you would raise the global_settings{ambient_light value} to increase the over all brightness in a non-radiosity scene, you can use brightness in a radiosity scene.

Count

Count defines the number of rays computed for each radiosity sample calculation.

Error bound

Error bound defines the level of tolerated errors. The lower you set it the better quality will be.

Gray_threshold

Gray threshold defines the participation of colors in radiosity calculation.

Low error factor

Low error bound is a corrective value for error bound used for pretrace calculations.

Max Sample

Max samples defines a limit to sample calculation for objects, in order to avoid too bright surfaces.

Minimum reuse

Nearest count

Pretrace

Affected by normals

Radiosity estimation can be affected by object normals.

Affected by media

Radiosity estimation can be affected by media.