POV-Ray : Newsgroups : povray.newusers : Lighting : Re: Lighting Server Time
5 Sep 2024 04:18:58 EDT (-0400)
  Re: Lighting  
From: JRG
Date: 12 Oct 2001 14:07:06
Message: <3bc7314a@news.povray.org>
You should try radiosity, together with a *properly shaped* area light if
you want.

--
Jonathan.
"Shalom" <sha### [at] homecom> ha scritto nel messaggio
news:3bc6e73a$1@news.povray.org...
> I've been using povray for some time now, but there's still one thing I
can't
> do properly - lighting. No matter what lighting model I use, it just
doesn't
> work.
>
> The problem is that I have a very, very large room, with 5 relatively
small
> objects in it. I am taking a couple of pictures of each of these objects
from
> several angles, as well as the whole room by itself. The problem is, that
even
> if I provide a large ambient value, Pov-ray does not shade shadows.
Therefore,
> if I only have 1 or 2 lights to light up this room, 1 side of all these
objects
> will always be in shadow, and not much better looking than a standard
scanline
> renderer.
>
> Of course, the first thing that comes to mind is an area light. However,
this
> doesn't work because the room is very, very large, and the objects are
spread
> around the room, and even an area light of 30 X 30 lights (which would
take
> HOURS to render) would still look like there are just 2 lights, 1 on each
side,
> which doesn't make very nice shadows.
>
> I could also put small area lights on top of each object, but that would
make
> it look like there's a lot of light concentration in a few areas in the
> pictures of the whole room.
>
> Currently, I'm using an interesting model I invented: 2 lights on the
exact
> same spot, both with 50% brightness, but one of them shadowless, and one
of
> them not. This way, shadowed areas are darker than non-shadowed areas, but
are
> still shaded.
>
> This method works quite well, but its not quite right. The best thing
would be
> this, but I don't think it's possible in Povray:
> Area lights, I believe, only use the extra light to calculate shadows, but
do
> all the shading based on the main light. It would be good to have the same
sort
> of thing as area lights, where the shading comes from 1 single spot, but
where
> the shadows are calculated based on a few lights just above each object.
This
> way, each object would have smooth shading, but one wouldn't need 100X100
> lights to cover a whole room, just a couple of lights for each object.
>
> Waiting for your ideas,
> Shalom
>


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