Le 17-07-28 à 05:44, gregors a écrit :
> Hello
> 
> Every time when I tried to render the scene I've got different results. The
> difference was in the lighting of the scene. In the scene there is only one HDR
> sky_sphere.
> 
> I am using official 3.7 build on Windows and unofficial MacOS build 3.7.1.
> 
> Is there something I've missed?
> 
> Here are two examples of the resulting image: https://ibb.co/gR9VkQ
> 
> Here is complete test scene:
> 
> #version 3.7;
> 
> #include "colors.inc"
> #include "finish.inc"
> 
> #default{
>    finish{
>      ambient 0
>      diffuse 1
Not a good idea. A value around 0.6 to 0.8 will give more realist 
results.> to    }
> }
> 
> global_settings {
>    radiosity {
>      pretrace_start 0.08
>      pretrace_end   0.04
Should be smaller, like 0.01 or even 0.005
>      count 35
MUCH to small for a pure radiosity scene. Ok in a scene using regular 
light_source.
Use at least 75, probably more.
Also, you should try the 2 parameters variation. The second value set a 
pool of samples directions. It help reduce artefacts.
try this :
count 160, 5555
> 
>      nearest_count 5
Maybe a little small.
Take advantage of the adaptive version :
nearest_count 5, 20
>      error_bound 1.8
Maybe a little smaller, like 0.9
This is OK when NOT using pure radiosity, but illuminating your scene 
with light_source.
>      recursion_limit 3
> 
>      low_error_factor .5
OK, but you may want to try something smaller here also. Good values 
range between 0.1 and 0.5
>      gray_threshold 0.0 // OK
>      minimum_reuse 0.015 // OK
>      brightness 1 // OK
> 
>      adc_bailout 0.01/2 // Probably OK
>    }
> }
> 
> sky_sphere{
>    pigment{
>      image_map {
>        hdr "..\kitchen_probe.hdr"
Take note that it's a single direction probe. It have a blind spot and 
you can see the camera.
>        map_type 1
>        interpolate 4
>      }
>    } // end of pigment
> } //end of skysphere -----
> 
> // perspective (default) camera
> camera {
>    location  <0.0, 1.2, -2.0>
>    look_at   <0.0, 0.5,  0.0>
>    right     x*image_width/image_height
> }
> 
> 
> // scene
> sphere{ <0,0,0>, 0.5
>    texture{
>      pigment{ DimGray }
>      finish{ Dull }
>    } // end of texture
>    translate <0, 0.5, 0>
> }
> 
> plane{
>    <0,1,0>, 0  hollow // normal vector, distance to zero ----
Why add «hollow»? It have absolutely no effect in this scene.
>    texture{
>      pigment{ Gray }
>      finish{ Dull }
>    } // end of texture
> }
> 
> 

Alain

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