On 12/12/2012 04:55 PM, Alain wrote:

>
>> Now I have a question .... because holy crap my first stab at photons in
>> this scene took 28 hrs and it just didn't suit. I think some of the rays
>> are getting through the gaps between the peppercorns. I've been reading
>> (and re-reading) the docs on photons and I'm unclear about the setup I'm
>> using. I'd like to trim some time off that process and here's what I
>> have:
>>
>> union {
>>    object { PepperMill scale 1.01 #if (UsePhotons) split_union off #end }
>>    object { Peppercorns #if (UsePhotons) split_union off #end }
>>    translate <-120,0,12.5>
>>    rotate y*60
>>    #if (UsePhotons)
>>      photons { target reflection on refraction on collect off }
>>    #end
>>    }
>>
>> The peppercorns are a union of all the peppercorns is why I did it like
>> that, and just wanted a reality check so I don't waste another 28 hrs!
>
> I'm not sure that turning split_union off help you. If the union is
> split, you stop checking if you hit any object of the union, but, if you
> don't split it, each ray must test against all of your 2000 peper corns,
> even those on the oposite side or in the middle that have no hope of
> ever interacting with your photons...
> Anyway, do a test using only mockup spheres and one photons target
> object shining photons on the whole thing. Compare with and without
> split_union off.
>
> Not splitting the union of the peper mill itself may help in some cases,
> but it also may not.
> Do a test render with the empty peper mill and simple planes to collect
> the photons and compare the performances with and without split_union off.
>
> You don't need to use the conditional expression for your photons block.
> In a non-photons scene, any photons block is just silently ignored.
>
>
> Alain

Thanks for the nudge ...

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