Alain Martel <kua### [at] videotronca> wrote:
> >
> > BTW:
> > I think that the docs'  'target' default of 1.0 [the numerical multiplier]
> > also needs a small clarification (...) The 1.0 value also works when
> > 'count' is used [instead of 'spacing'] but incrementally changing the float
> > value has no effect.
> >
>
> The value after target has an effect on the density of the photons for
> the target object.
>
> Even when using count, target 0.5 should cause that object to receive 4
> times as many photons compared to target 1/on/true. When using count,
> this only has an effect when there are at least two target objects.
>

My original tests used only one 'target' object, so I tested again using two,
and you're right: A changed multiplier value does work now (for both targets),
even when 'count' is used in the global photons block. This little 'switch' in
behavior is undocumented, as far as I can tell.

However: Given two (or more) 'target' objects in a scene, the photon behavior
for each can be unexpectedly different, depending on whether 'count' vs.
'spacing' is used:

A) With 'count':
     If two targets both use a value of 1.0 (or simply 'on'), the 'count' of
     photons is *split up evenly* between the two; each target gets half the
     count. But if one target uses 1.0 and the other 0.2, the 0.2 target *robs*
     photons from the 1.0 target, with the resulting visual caustic effect on
     surfaces looking different from each one. But the total photon
    'count' remains the same.

B) With 'spacing':
     Each target is *independent*-- they each respond to their individual
     spacing-multiplier values, no 'robbing' of photons...which means the total
     NUMBER of photons can increase, to suit the situation. This would
     produce a more logical and visually realistic result than 'count'.

Some of these behavioral differences are undocumented as well, or at least not
clearly.

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