On 09/20/2012 01:34 AM, Alain wrote:

>> On 09/17/2012 07:28 AM, James Holsenback wrote:
>>> Already tried that incantation. Still think photons and light_group is a
>>> no go. I'll prepare a better example when I get a chance.
>>
>> OK ... below is a simplified scene used to show the problem I'm having.
>> The scene is initially setup with the Key_Light as the photon source and
>> /without/ the light_group ... it shows that indeed it does shoot photons
>> properly.
>>
>> Now remove comments from around the light_group code in the Ring
>> definition, and in the Key_Light change reflection/refraction from /on/
>> to /off/ (now I want the Stone_Light to be the photon source) and see
>> what I mean.
>>
>> Maybe not related but why does the stone shadow /still/ appear to be
>> coming from the Key_Light and /not/ the Stone_Light ... I have
>> global_lights set to off in the light_group!
>>
>
> It looks like photons from a light_group are indeed broken. They don't
> even show on an added object added in the light_group placed to receive
> them.
 >
> Any object can intercept light from any light and cause shadows. The
> appartenance to a light_group don't change that.
> Also, any object outside the light_group can cause shadow on an object
> of a light_group if it's situated between the light and it's associated
> object(s).
>
> The only objects that don't cause shadows are those having an explicite
> no_shadow attribute.
> The only light that don't cause any shadow are shadowless ones. They
> also never cause any highlight and, by default, never cast any photons.
> I don't know if you can force a shadowless light to cast photons by
> adding photons{refraction on reflection on}.
>
> Remove caustics 1.0. It's only good at simulating caustics under a body
> of water on a relatively flat and level surface.
>
> There is no reason to remove the photons block in a non-photons scene or
> in a test render without photons. In this case, the photons block will
> simply be ignored.
>
> In the global_settings, you must NOT use both spacing and count in the
> photons block. Use only one OR the other.
>
> autostop 1 is the same as not using autostop.

thanks for the sanity check (i'll file a bug report) and the additional 
information is also useful as photons use is one of my weak areas.

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