William F Pokorny <ano### [at] anonymousorg> wrote:
> On 03/20/2017 10:30 AM, muyu wrote:
> >
> > No ideas at the moment. Maybe if you posted the resulting images, the
> > distribution of light within the canopy might give a hint.
> >
> > Here it is the setting of the radiosity:
> > #version 3.7;
>  >.....
> > disc {<9.5780,-10.5050,0.6040>, <0.7070,0.1830,0.6840>, 0.0500
> > texture {leaf_text}}
> > .....
> >
> > diffuse 0.4957 is front diffuse, 0.4409 is the transmitted light? Should I set
> > rgbt or rgbf?
> >
> > Is this the right way to consider the multi-scattering using Radiosity? I have
> > the impression that some processes are missing?
> >
> > Thax in advance.
> >
> Not been following closely, but on seeing some images and code some a
> few thoughts pop into my head.
>
> Just a thought, but in play here is perhaps that the 'disc' object has
> no thickness. This means rays which are nearly parallel with the plane
> of a disc will resolve somewhat noisily (more light transport than
> should be I suppose) and also that light will not attenuate/scatter in
> the leaf's thickness(1).
>
> Perhaps give us a short description of your Monte Carlo simulation
> "standard." Is this also done in POV-Ray? A stand along program or?
>
> Aside: I thought the second diffuse parameter required a proceeding
> comma, but if working OK for you must not be the case... :-)
>
> Bill P.
>
> (1) - More accurate leaves could be modeled in POV-Ray, but suspect it
> would be costly in terms of complexity and compute resource.

Thanks. The Monte Carlo simulation was generated by other softwares. I did not
know much details about it. But they were considered as the reference to
evaluate other methods.

1) Disc of negligible thickness...the same as in the Monte Carlo methods.

2) Now my simulations using Pov-ray radiosity were around 5 to 10% lower than
the reference even I set the recursion time as 20. I am wondering if Pov-ray
miss some physical processes or I can further improve the accuracy by tunning
some parameters. Brightness or light intensity etc...?

Thanks in advance.

Shouyang

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