POV-Ray : Newsgroups : povray.newusers : How do I stop background colour colouring everything in my scene : Re: How do I stop background colour colouring everything in my scene Server Time: 20 Jun 2019 19:28:35 GMT
  Re: How do I stop background colour colouring everything in my scene  
From: Alain
Date: 25 Feb 2019 19:02:39
Le 19-02-25 à 10:01, cloudyroo a écrit :
> "omniverse" <omn### [at] charternet> wrote:
>> "cloudyroo" <nomail@nomail> wrote:
>>> If I add a blue background to a scene with a grey floor and white sphere I end
>>> up with a pretty blue everything (like so: https://imgur.com/a/w9dF3Q1).
>>> Is there a way to stop this or another way to colour only the sky/background?
>>> Thanks!
>>
>> You seem to be using radiosity; if so, try adding the keyword gray_threshold (or
>> grey_threshold) to that part of your scene and use a value greater than the
>> default of 0.
>> It will diminish color transference by that amount as a percentage, 0.5 being
>> 50%.
> 
> Won't that lessen transference of colours from everything?
> The description of background says "Any ray that does not hit an object will be
> colored with this color". I'd thought that would mean it's solely a background
> color and doesn't interact with the scene.
> Is there no way to achieve that effect without changing the way objects in the
> scene interact with eachother?
> 
> 

You may add a large sphere around your scene as follow :

sphere{0 e5 // Very large
    pigment{rgb 0.5} // Tweak to your taste
    finish{diffuse 0 ambient 0 emission 1}
  // Won't be affected by lights nor radiosity
    no_image // So that you don't see it directly
    no_reflection // So that it don't appears in reflections
    no_shadow // Just in case you have any light outside the sphere
    hollow // to suppress a warning and allow the use of fog and medias
  }



Alain


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