POV-Ray : Newsgroups : povray.newusers : shiny plastic : Re: shiny plastic Server Time
20 Jun 2021 20:11:18 EDT (-0400)
  Re: shiny plastic  
From: Thomas de Groot
Date: 15 Oct 2018 02:30:47
Message: <5bc43417$1@news.povray.org>
On 14-10-2018 19:25, Stephen wrote:
> On 14/10/2018 16:55, Alain wrote:
>> Le 18-10-13 à 15:04, Stephen a écrit :
>>> For testing your TV material. Create a sphere with a no image flag. 
>>> This will allow the reflections of the sphere to be shown in the 
>>> reflections of your TV. Convert a HDRi to a png and create a material 
>>> using this and attach it to the sphere. The reflections should show up.
>>> Aside, some HDR images are in a cruciform format which should be used 
>>> with a box not a sphere.
>>>
>>> You can download some HDRIs from here:
>>> https://hdrihaven.com/hdris/category/?c=all
>>>
>>>
>>
>> There is no need to convert the HDRI to any other format as HDRI is 
>> directly supported in version 3.7 and later. You can use *.HDR or 
>> *.EXR files.
>>
>> For a rectangular longitude-latitude image :
>> sphere{0 Radius pigment{image_map{ hdr "Name.hrd" map_type 1 
>> interpolate 1} scale <-1,1,1>}finish{diffuse 0 emission 1}}
>>
>> The scale is to flip the image so that it show in the correct 
>> direction from the inside of the sphere.
>> Some probes may be to bright or dim. Adjust emission to get correct 
>> results.
>>
>>
> 
> 
> Of course you are right. I am still, mostly, using Pov ver 3.62 SDL.
> I really look forward to the news before the end of the year. :)
> 
> Apologies to David but the point still stands. Radiosity is a subject in 
> itself and takes time. In my opinion.
> 

One can diverge on this though ;-) In most if not all of my scenes, I 
have radiosity switched on from the start, and I rarely change the 
settings, with the exception of recursion_limit, media, and normal, 
which I adapt to the needs specific of my scene. See a sample xode 
example below (watch out for line breaks when copying):

   radiosity {
     pretrace_start 0.08           // start pretrace at this size
     pretrace_end   0.004          // end pretrace at this size
     count 50, 1000                // higher -> higher quality (1..1600) 
[35]
     nearest_count 10, 5           // higher -> higher quality (1..10) [5]
     error_bound 1                 // higher -> smoother, less accurate 
[1.8]
     recursion_limit 2             // how much interreflections are 
calculated (1..5+) [2]
     low_error_factor .3           // reduce error_bound during last 
pretrace step
     gray_threshold 0.0            // increase for weakening colors 
(0..1) [0]
     minimum_reuse 0.015           // reuse of old radiosity samples [0.015]
     maximum_reuse 0.1							    brightness 1                  // 
brightness of radiosity effects (0..1) [1]

     adc_bailout 0.01/2
     normal off                   // take surface normals into account [off]
     media off                    // take media into account [off]
     always_sample off           // turn sampling in final trace off [on]
     //max_sample 1.0              // maximum brightness of samples
   }


-- 
Thomas


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