It was mentioned in another thread that beta 3.7 treats radiosity differently.
How has it changed, or where can I find information on that? Of the greatest
importance to me, is how radiant intensity calculated for radiosity is
influenced by diffuse and ambient settings (both global and object).

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On 21.02.10 05:40, Ken Willmott wrote:
> It was mentioned in another thread that beta 3.7 treats radiosity differently.
> How has it changed, or where can I find information on that? Of the greatest
> importance to me, is how radiant intensity calculated for radiosity is
> influenced by diffuse and ambient settings (both global and object).

Your best source of information are the release notes. They come with every 
beta and are available on the download website.

	Thorsten

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> It was mentioned in another thread that beta 3.7 treats radiosity differently.
> How has it changed, or where can I find information on that? Of the greatest
> importance to me, is how radiant intensity calculated for radiosity is
> influenced by diffuse and ambient settings (both global and object).
>
>

Mostly, all object must have ambient set to zero unless they are to 
actualy emit light. This have not changed since radiosity was introduced.

Diffuse determine how an object will affect it's surrounding depending 
on the illumination it receives. No major changes from previous versions 
in the basic principles.

The main differences is in HOW the sampling is actualy done and the 
multi-threaded capability allowing you to benefit from multicore CPUs 
and multiple CPUs.
Also, some radiosity settings work a little diferently in the beta.

/Most/ radiosity should render the same as with version 3.6.

For all radiosity scenes, whatever the version used, you should have:
#default{finish{ambient 0}} early in your scene. Best place: before any 
#include and #declare of texture and material.

Seting ambient_lights 0 or some very small value is NOT something to do, 
as it will screw things whenever you have some ambient light source.
The purpose of that setting is to tint the ambient component of the finish.

Then, check any include and alter them so that they don't set any 
ambient unless the finish obviously should emit light, as the Luminous 
finish.


Alain

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Alain <aze### [at] qwertyorg> wrote:

> > It was mentioned in another thread that beta 3.7 treats radiosity differently.
> > How has it changed, or where can I find information on that? Of the greatest
> > importance to me, is how radiant intensity calculated for radiosity is
> > influenced by diffuse and ambient settings (both global and object).
> >
> >
>
> Mostly, all object must have ambient set to zero unless they are to
> actualy emit light. This have not changed since radiosity was introduced.
>
> Diffuse determine how an object will affect it's surrounding depending
> on the illumination it receives. No major changes from previous versions
> in the basic principles.
>
> The main differences is in HOW the sampling is actualy done and the
> multi-threaded capability allowing you to benefit from multicore CPUs
> and multiple CPUs.
> Also, some radiosity settings work a little diferently in the beta.
>
> /Most/ radiosity should render the same as with version 3.6.
>
> For all radiosity scenes, whatever the version used, you should have:
> #default{finish{ambient 0}} early in your scene. Best place: before any
> #include and #declare of texture and material.
>
> Seting ambient_lights 0 or some very small value is NOT something to do,
> as it will screw things whenever you have some ambient light source.
> The purpose of that setting is to tint the ambient component of the finish.
>
> Then, check any include and alter them so that they don't set any
> ambient unless the finish obviously should emit light, as the Luminous
> finish.
>
>
> Alain

I've implemented that setting. I now use:
#default{finish{ambient 0 diffuse 1}

It's a good idea, but I run into trouble with skies. Since radiosity (by my
experiment) uses both ambient and diffuse light, I get into a juggling act with
trying to illuminate both the camera and the scene evenly. It's hard to balance
the direct light from the sky to make it look natural, and have the right
illumination level in the shadows. I use light groups to colour balance as well,
so things can get complicated.

I believe this setting would be over-ridden by libraries, which isn't too great.
Of course, it won't affect textures defined in your sources.

The weird thing for me now is that radiosity doesn't seem to respect (or
understand) light groups. I know this is a curious complaint, and even way ahead
of my own needs, but it raises interesting questions in my mind...

Such as, should the radiosity for an object be calculated using only the light
sources in its light group?
Currently, it seems to me that this is not the case.

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> Alain<aze### [at] qwertyorg>  wrote:

>>> It was mentioned in another thread that beta 3.7 treats radiosity differently.
>>> How has it changed, or where can I find information on that? Of the greatest
>>> importance to me, is how radiant intensity calculated for radiosity is
>>> influenced by diffuse and ambient settings (both global and object).
>>>
>>>
>>
>> Mostly, all object must have ambient set to zero unless they are to
>> actualy emit light. This have not changed since radiosity was introduced.
>>
>> Diffuse determine how an object will affect it's surrounding depending
>> on the illumination it receives. No major changes from previous versions
>> in the basic principles.
>>
>> The main differences is in HOW the sampling is actualy done and the
>> multi-threaded capability allowing you to benefit from multicore CPUs
>> and multiple CPUs.
>> Also, some radiosity settings work a little diferently in the beta.
>>
>> /Most/ radiosity should render the same as with version 3.6.
>>
>> For all radiosity scenes, whatever the version used, you should have:
>> #default{finish{ambient 0}} early in your scene. Best place: before any
>> #include and #declare of texture and material.
>>
>> Seting ambient_lights 0 or some very small value is NOT something to do,
>> as it will screw things whenever you have some ambient light source.
>> The purpose of that setting is to tint the ambient component of the finish.
>>
>> Then, check any include and alter them so that they don't set any
>> ambient unless the finish obviously should emit light, as the Luminous
>> finish.
>>
>>
>> Alain
>
> I've implemented that setting. I now use:
> #default{finish{ambient 0 diffuse 1}
>
> It's a good idea, but I run into trouble with skies. Since radiosity (by my
> experiment) uses both ambient and diffuse light, I get into a juggling act with
> trying to illuminate both the camera and the scene evenly. It's hard to balance
> the direct light from the sky to make it look natural, and have the right
> illumination level in the shadows. I use light groups to colour balance as well,
> so things can get complicated.
>
> I believe this setting would be over-ridden by libraries, which isn't too great.
> Of course, it won't affect textures defined in your sources.

Any finish that set ambient to any valus always override the default. 
That's by design. Otherwise, there would be no way to have any texture 
other than the default.
Several include libraries where made for versions 1, 2 and early 3 
before radiosity's introduction. Several textures used unrealistic 
ambient setings to "make them look good". metals.inc and golds.inc are 
main offenders in that domain and use some insane ambient values for all 
defined textures.
Some textures from stone.inc and texture.inc also have high ambient 
finishes.

>
> The weird thing for me now is that radiosity doesn't seem to respect (or
> understand) light groups. I know this is a curious complaint, and even way ahead
> of my own needs, but it raises interesting questions in my mind...
>
> Such as, should the radiosity for an object be calculated using only the light
> sources in its light group?
> Currently, it seems to me that this is not the case.
>
>

Radiosity sampling don't bother with actual light_source. If an object 
is illuminated, it have an effect on the radiosity samples.

So, any object, not part of a light_group, near an object in a 
light_group WILL receive some light indirect from that object in exactly 
the same way it would if tere was NO light_group at all.
Same thing for any object IN a light_group near any object outside it's 
own light_group. Those will be affected by the indirect light from any 
nearby object.

If, for any reason, you don't want the objects from the light_group to 
affect the radiosity sampling, you can add "no_radiosity". Keep in mind 
that this will also disable those object radiosity effect on other 
objects from the light_group.
That flag is valid ONLY with the latest and future betas.
It act just like no_reflection, no_shadow and no_image.
no_radiosity make the affected object invisible to radiosity rays.


Alain

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