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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"Shalom" <sha### [at] homecom> wrote in message
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.
>

Have you tried radiosity?

- Nekar


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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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Or a shadowless light source at the camera location.
Alberto.

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