Am 31.03.2017 um 19:08 schrieb muyu:
> clipka <ano### [at] anonymousorg> wrote:
>> Am 24.03.2017 um 00:14 schrieb muyu:
>>
>>> For each leaf, 0.4957 is scatted directly. 0.4409 is transmitted and scatted. So
>>> as I understood, I should not use any filter. The two sides diffuse is the right
>>> choice. Am I right?
>>
>> Yes, you are.
> 
> For different wavelength, reflectances and transmitances vary a lot. Is it
> possible to set different value for different channels? I can save the radiosity
> data and reuse for other wavelength? My objective is to save the render time for
> different channels.

Currently the colours for reflectance and transmittance are both tied to
the pigment.


> Thanks. I build my own POV-Ray and change the DEPTH_MAX to 20000. Then the
> recursion limit comes to be 255. Is it right?

Something in that ballpark, at any rate.


> Surprisingly, the reflectance increases very very silightly even when I set
> recursion at 255. Here is the setting of the radiosity. I am wondering if I can
> further increase the reflectance. It is still 5 to 10% underestimate. Still some
> light is not absorbed?

A maximum recursion setting of 255 should be more than enough; I'm a bit
at a loss where the remaining light is swallowed -- are you sure your
reference is correct?


> Here it the *.ini file. I output the image as *.png. The transfer is linear? The
> setting of Antialias impacts the result...the Antialias_gamma = 1.0 or 0.0?

When using `File_Gamma=1.0`, PNG output does indeed use linear transfer.

`Antialias_Gamma` is not the colour space in which oversampling averages
are computed (that's always done in linear colour space) but rather the
colour space in which it is tested whether colours of adjacent pixels
are different enough to warrant oversampling. The default value should
be fine.

> 
> Antialias = on
> Antialias_Threshold = 0.0
> Antialias_Depth = 5
> Antialias_Gamma = 1.0
> Input_File_Name = "canopy_ERE_NIR.pov"
> File_Gamma = 1.0
> 
> width = 4000
> height = 4000
> 
> Pov-ray uses radiosity to simulate the diffuse light. Compared with Monte Carlo,
> physically we should get very similar result?

I think we should get virtually identical results, plus/minus some noise
(white noise in case of Monte Carlo, lower-frequency noise in case of
radiosity).

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