"Hugo" wrote:
> JRG wrote:
> > add an ambient 20 sky inside the one used for the global
> > illumination and put the no_image flag into it
> >
> > What I do here (and what I did elsewhere) is to add the
> > no_image flag to the wall where the window is... it looks
> > right, it doesn't need damn high settings hence the
> > low render time. :-)
>
> Thanks! I just read in the POV docs about the no_image keyword, because it
> seems strange to me that this should work any different than having a real
> wall to block the light.
>
> From what I understand, the faked wall will actually emit a strong light
> (because of ambient 20) but it isn't visible to the camera, only radiosity
> reacts to it.. And perhaps objects with reflection reacts to it also, in
> which case these objects will need uncommon finish statements.
>
> Sounds strange that this should allow for lower settings for radiosity.
>
> I'll experiment when I get the time.
> You are welcome to post an example.

Excuse my bad explanation.
Let's try again: :o)

first of all, keep in mind that no_image objects do not affect radiosity. This means
that I use the no_image flag because I don't want the object to affect radiosity yet
I want it to be visible through the reflections.
That said:
I don't use ambient 20 with the wall. I use it with a sphere, which I put inside the
*real* sky_sphere. Ambient 20 would mess up my radiosity setup, so I also use the
no_image flag in order to make this sky only visible through the reflections. It is
this very bright sky which causes those nice window highlights on the reflective
objects. Of course you also need another skysphere in order to light the scene.
As for the wall, I use the no_image flag so that the scene is lit just as if the wall
were not there. You see the wall in the reflections (actually the drawback is that it
is completely black) but it doesn't affect radiosity, and the skylight has so much
more room to pass through. This is the key: the no_image wall does _not_ block the
light.

--
Jonathan.

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