Le 19-07-02 à 04:48, Deepak a écrit :
> Alain <kua### [at] videotronca> wrote:
>> Le 19-06-28 à 06:13, Deepak a écrit :
>>> Hi,
>>>
>>> I am new to try with Povray application. I am trying to test performance of
>>> various compiler like (gcc, clang) on CPU with
>>> scenes/advanced/benchmark/benchmark.pov (as suggested here-
>>> http://www.povray.org/download/benchmark.php)
>>>
>>> What I observed is the rendering is finishing in ~1.5 seconds only.
>>> So it's difficult to compare the results with various compiler for such short
>>> duration.
>>>
>>> Is there any large data set which runs for considerable time? or how to change
>>> or what parameter to change on .ini file to run it with considerable time.
>>>
>>>
>>> Thanks in advance for your help,
>>> Deepak
>>>
>>>
>>
>> Some things that you can do that will increase the rendering time :
>> (original values from the ini file)
>> For the INI file :
>> Increase the resolution. Something like 4000 by 4000 (512 by 512)
>> Lower the antialias threshold to 0.01 (0.3) and Sampling_method=2 (1)
>> Set High_Reproducibility=on (off)
>>
>> Within the scene itself :
>> Turn radiosity ON (this will have a large effect):
>> #declare use_radiosity = true; (false)
>> In the global_settings block:
>> Set max_trace_level to 255 (12)
>> Increase the radiosity count to 800 (80)
>> Set nearest_count to 20 (5)
>> Reduce error_bound to 0.2, or even 0.1 (0.5)
>> Change low_error_factor to 0.2 (0.5)
>> Increase recursion_limit to 3 (1)
>> Increase the photons quality:
>> Set photons{spacing 0.001} (0.007) [this will multiply the number of
>> photons shot by 49]
>>
>> Change the area_light:
>> light_source {
>>      <-0.7, 0.83, 0.24>*150000
>>      color rgb <3.43,2.87,1.95>
>>      #if (use_area_light=true)
>>         area_light 4000*x 4000*y  129,129 (4,4)
>>     adaptive 3 //added Will start sampling at 9 by 9
>>         jitter
>>         orient
>>         circular
>>      #end
>>
>>      media_attenuation on
>>      media_interaction on
>>
>> }
>>
>> In the definition of M_Watx4, add dispersion :
>>      interior {
>>         ior 1.31
>> dispersion 1.01 //added
>> dispersion_samples 20 //added, default = 7
>>         fade_distance 0.8
>>         fade_power 1001.0
>>         fade_color <0.02, 0.20, 0.06>
>>      }
>> Do the same for Mat_Glass :
>>      interior {
>>         ior 1.5
>> dispersion 1.02 //added
>> dispersion_samples 20 //added
>>         fade_distance 0.12
>>         fade_power 1001
>>         fade_color <0.6, 0.5, 0.7>
>>      }
>>
>> Change the media used for the clouds:
>> samples 120 (7,7)
> 
> 
> Hi Alain,
> 
> Thanks for your suggestion. I tried changing benchmark.pov and benchmark.ini
> files and observed that render time is increased too much. The application is
> running for hours. Is it expected?

Absolutely.

ALL of my suggestions are intended at making the render time go up.
Some, like radiosity and area_light, affect the rendering speed for 
every pixel. Anti aliasing make higher contrast areas take longer. 
Other, like adding dispersion, only affect the areas where you have 
transparent objects.

Increasing the resolution mean that there are now WAY more pixels to render.

> Also let me know if any specific option to run/render in parallel on multicore
> system.

POV-Ray version 3.7 automatically use all available cores.

> 
> I will Try your another suggestion too and update.
> 
> Thanks,
> Deepak
> 
> 

To see the impact of «adaptive», try adaptive 0 and compare with adaptive 3.

You can safely reduce the radiosity count to something more reasonable, 
like something in the 60 to 100 range.

I don't think that you ever reach the max_trace_level.

An anti aliasing threshold of 0.01 is uselessly low. Something like 0.05 
to 0.1 is more reasonable.


Alain

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