Documentation Talk:Reference Section 3.2

"An object can have both radiosity and an ambient term. However, it is suggested that if you use radiosity in a scene, you either set ambient_light to 0 in global_settings, or use ambient 0 in each object's finish. This lighting model is much more realistic, and POV-Ray will not try to adjust the overall brightness of the radiosity to match the ambient level specified by the user."

This is no longer true as of version 3.7.0 beta 38, as it automatically forces ambient_light to 0 in radiosity scenes (or, more true to the inner workings, pretends that the user had set it to 0), providing a dedicated mechanism instead for modelling glowing objects (emission).

maximum_reuse

The maximum_reuse parameter now governs the maximum effective radius of a sample more directly. When a new sample has been gathered after sample lookup returned insufficient samples, sample lookup is no longer run again; instead, the new sample is interpolated with the results of the earlier lookup. The actual number of samples required to satisfy the nearest_count setting is now influenced by sample quality, with high-quality samples reducing the effective number of samples required (down to 1/4 of the parameter value in extreme cases) and low-quality samples increasing the number, however this may change the balance between speed and quality for some scenes.

The above text is bogus; from the second sentence onward, it pertains to nearest_count instead (where it actually appears as well). The first sentence is probably rather obscure not only to new users, but also to users switching from POV-Ray 3.6 to 3.7, as the parameter does not exist in 3.6; the sentence pertained to a change between two betas in how the parameter works. The parameter's current functionality is akin to that of minimum_reuse, with the only difference that it is an upper bound rather than a lower one. (A similar functionality did already exist in 3.6, but the parmater was hard-coded. Some 3.7 beta exposed it to the user, while a later one changed details of the functionality to match that of minimum_reuse.) I suggest having a combined entry for both minimum_reuse and maximum_reuse.