[Bf-cycles] BPT Caustic Samples?

[Brecht Van Lommel]

The simple answer is: no, adding a Caustic Samples parameter to
branched path tracing is not possible. By the time you know you're
tracing a caustic path you've already taken the sample.

On Tue, Aug 23, 2016 at 6:54 PM, Zauber Paracelsus <zauber at gridmail.org> wrote:
> Okay, are you trying to tell me how to implement it in blender's code or
> something?  Because I was just asking if it was possible.  I won't be able
> to implement it myself, as my current knowledge of C++ is only sufficient to
> make minor tweaks.
>
>
>
> On 08/23/2016 12:33 PM, Mohamed Sakr wrote:
>
> I know what do you mean, you want a sampling for caustics only, let's see
> how caustics are created:
> ray emit from the camera, hit a diffuse surface, bounce to a
> glossy/refraction surface (with low roughness), hit the light.
> so to get a better caustics you will need to increase diffuse samples.
>
> but on the material side, you can catch indirect caustics, but using is
> singular ray and is glossy/refraction rays for low roughness shaders.
>
> to catch direct caustics, you will need first bounce to be "is diffuse ray?"
> when your actual shader is a glossy/refraction material.
> to reduce caustic noise you will need to increase roughness of your
> glossy/refraction shader after the diffuse ray. (this will allow to catch
> more light paths).
> hope I didn't mess anything, if I mentioned anything wrong others may
> correct, thanks.
>
> On Tue, Aug 23, 2016 at 6:20 PM, Zauber Paracelsus <zauber at gridmail.org>
> wrote:
>>
>> Could you clarify your meaning?
>>
>> On 08/23/2016 12:09 PM, Mohamed Sakr wrote:
>> > I guess you can catch caustic samples using is singular ray?
>>
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