[Radiance-general] ambient bounces

[Jia Hu]

Sorry, I just want to clarify my question.

For the methods used in Radiance, there are three parts to calculate: direct
component, specular indirect component, and diffuse indirect component.

For the direct and specular components, the value of contribution is got by
hitting the source, is there any limit for the number of bounces for these
two component?

 But for diffuse component, how can we define the value after the number of
bounces (the value of "ab" ) is exceeded since the diffuse
component considers those without hitting any source? The rays hitting the
source will be discarded because the other components have considered them.

Thank you,
jia

On Tue, Apr 20, 2010 at 7:39 AM, Jia Hu <hujia06 at gmail.com> wrote:

> Thank you very much, Christopher and Thomas.
>
> If I specify the value of "-av", does that mean the ray without hitting a
> source will get some values (or contribution) that is related to "av". In
> other words, "av" makes ray without hitting a source have some
> contributions?
>
> Regards,
> Jia
>   On Tue, Apr 20, 2010 at 5:02 AM, Thomas Bleicher <
> tbleicher at googlemail.com> wrote:
>
>> Jia.
>>
>> If the number of bounces is exceeded without hitting a source or
>> infinity the value specified with "-av" (ambient value) is used. The
>> default value is "0 0 0" so you won't get any artificial contribution.
>>
>> You can use rvu to read the average value of a scene on the screen.
>> This gives you a first approximation of -av.
>>
>> Regards,
>> Thomas
>>
>> On Tue, Apr 20, 2010 at 6:11 AM, Jia Hu <hujia06 at gmail.com> wrote:
>> > Hello all:
>> >
>> > If ab (ambient bounces) =3, after a ray reaches three times of diffuse
>> > bounces and does not hit any lighting source, then how should Radiance
>> > define the value of this ray, for example, radiance or irradiance, in
>> order
>> > to calculate the radiance at the viewpoint using backward ray tracing?
>> I
>> > read chapters about calculation methods in the book, Rendering with
>> > radiance, but still a little confused.
>> >
>> > Thank you in advance.
>> > Jia
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>> >
>> >
>>
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