Hello!

I'd like to know, whether someone has used radiosity for rendering scene
with computer monitor in dark room? I want to create such scene and it
seems just to ask for radiosity. But if I use radiosity, then image on
computer screen gets smeared and patchy (I use image_map for computer
screen contents). Has someone done this before and which radiosity
settings were used in such case? Or will I be better off with just
adding area light before computer screen?

Thanks in advance!

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Fact is that the radiosity picks up on even the darker areas and
propagates them into the diffuse reflection too. So what happens is you
can mess up the object textures when highly contrasting textures (or
environment) exist. You could try lowering the distance_maximum to negate
the effect on it but that particular setup, ie. monitor in darkened room,
is just plain going to be tough I think. Mainly because I'm sure you want
the screen glow to react with nearby objects, maybe even a distant wall. I
would suggest a white unseen plane somewhere like just behind the camera
or something but you'd simply get the white from it showing up everywhere
too.
There's a chance that you could make the image_map finish with a very high
ambient and low diffuse. I'm conjecturing a lot here, but what the heck.

This brings to mind a possible solution if POV-Ray itself were changed. A
container based radiosity instead of global. Similar to media and fog. Oh,
well, there's my thoughts.


Vahur Krouverk wrote:
> 
> Hello!
> 
> I'd like to know, whether someone has used radiosity for rendering scene
> with computer monitor in dark room? I want to create such scene and it
> seems just to ask for radiosity. But if I use radiosity, then image on
> computer screen gets smeared and patchy (I use image_map for computer
> screen contents). Has someone done this before and which radiosity
> settings were used in such case? Or will I be better off with just
> adding area light before computer screen?
> 
> Thanks in advance!

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Vahur Krouverk wrote:

> Hello!
>
> I'd like to know, whether someone has used radiosity for rendering scene
> with computer monitor in dark room? I want to create such scene and it
> seems just to ask for radiosity. But if I use radiosity, then image on
> computer screen gets smeared and patchy

    I haven't used Radiosity that much... but the first thing that came to
mind was the radiosity settings themselves.  The doc's plainly say that this
sorta thing can happen if the param's aren't set high enough.
May I suggest really CRANKING the settings?   (note,  this is SLOW,  REALLY
SLOW!)  Pay close attention,  as some of these will probably have to be
changed based on the distance/scale/units of your particular scene.


 radiosity {
               count 1990                // Ensure that we get good,
accurate samples
               error_bound 0.1          // And calculate lots of them.
(more important than count)
               gray_threshold 0.5
               distance_maximum 4         // Scene-dependant!
               low_error_factor 0.7        // force many extra samples to be
calculated...
               nearest_count 9               // so we can average them
together for smoothness
               minimum_reuse 0.001     // get quite tightly into corners
               brightness 3.3                // doesn't really matter.  Not
used in final output.
               recursion_limit 1           // Try this = 2, but drop the
count to maybe 300
            }

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