Am 14.11.2017 um 10:57 schrieb Stephen:
> On 14/11/2017 08:03, Thomas de Groot wrote:
>> On 13-11-2017 21:27, Stephen wrote:
>>> The tunic and wings are emissive df3s, made from Poser models.
>>>
>>> I think I need a dragon and a rocky scene to complete this. :)
>>>
>>>
>>
>> Yes indeed although I like this ballet school setting with the mirrors. 
> 
> It is old enough to have been made in Moray. :-)
> 
>> A couple of things, if I may: (1) the overhead lights should be dimmed
>> - probably by at least 50 % (if not 25%) also for compensating the
>> light reflections from the mirrors. 
> 
> The lighting is problematic. The light in the hall of mirrors brightens
> when I switch on radiosity. I did not mean this to turn into an
> experiment in radiosity but it looks looks like it is going to be. I
> have a normal area light in there to even things out.

Problems with different "quality levels" of illumination are to be
expected here, due to the huge mirrors as well as the glowing wings.


In reality, objects in the room would be lit by...:

(1) Light coming directly from the light sources.

(2a) Light bouncing off diffuse objects.
(2b) Light emitted by glowing stuff.

(3a) Light bouncing off diffuse objects and then the mirrors.
(3b) Light emitted by glowing stuff and bouncing off the mirrors.

(4) Light coming from the light sources and bouncing off the mirrors.

(5) Light bouncing off the mirrors and then diffuse objects.


To simulate (1), "classic" raytracing will do.

To simulate (2) and (3), you need to enable radiosity.

To simulate (4), you need to enable photons.

To simulate (5), you need to enable both radiosity and photons.

If any of these are not simulated, the corresponding portion of
illumination will simply be missing, causing the image to appear darker.

The lack of illumination from (2), (3) and (5) can be compensated for to
some degree, by making use of the "ambient" mechanism.


As far as overall brightness goes, you should ideally use renders with
radiosity and photons as a yardstick, and set up "ambient" accordingly
for fast test renders.

(As a faster alternative to photons for this particular scene, you might
try using mirrored copies of your primary light sources,
`projected_through` the corresponding mirrors. Make sure to properly
account for any dimming effect if your mirrors aren't 100% reflective.)

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