Translations:Tutorial FreeCAD POV ray/48/en

Like other objects, the light can be modified with many options. The option creates a rectangular source, which is more realistic as it results in diffuse illumination that creates soft shadows. The keyword helps reduce the computation time of the light paths; the larger the value the more accurate the result will be; to avoid long rendering times you should use the smallest integer that gives an acceptable result ( or  is usually enough); to obtain the best result remove the keyword completely (long rendering time). The keyword helps improve the shadows by randomly shifting the position of the lights. The keywords and  turn the area light into a spherical source, which will produce better shadows when there are rounded objects in the scene. Including and  is helpful to attenuate the value of the light with distance, just like it happens with a real light source.