POV-Ray : Newsgroups : povray.general : Emissive object not showing up Server Time
28 Mar 2024 21:40:40 EDT (-0400)
  Emissive object not showing up (Message 1 to 5 of 5)  
From: Mike Horvath
Subject: Emissive object not showing up
Date: 6 Aug 2018 07:55:25
Message: <5b68372d$1@news.povray.org>
I have created this object at the center of my scene, but it is not 
visible. What mistakes have I made? Thanks.

Mike


sphere
{
	0, RWorld_Sun_Radius
	hollow
	material
	{
		texture
		{
			pigment {rgbt 1}
		}
		interior
		{
			media
			{
				emission 100000
				density
				{
					spherical
					density_map
					{
						[0 rgb 0]
						[1 rgb 1]
					}
					scale RWorld_Sun_Radius
				}
			}
		}
	}
}


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From: Le Forgeron
Subject: Re: Emissive object not showing up
Date: 6 Aug 2018 11:18:35
Message: <5b6866cb$1@news.povray.org>
Le 06/08/2018 à 13:55, Mike Horvath a écrit :
> I have created this object at the center of my scene, but it is not
> visible. What mistakes have I made? Thanks.
> 
> Mike
> 
> 
> sphere
> {
>     0, RWorld_Sun_Radius
>     hollow
>     material
>     {
>         texture
>         {
>             pigment {rgbt 1}
>         }
>         interior
>         {
>             media
>             {
>                 emission 100000
>                 density
>                 {
>                     spherical
>                     density_map
>                     {
>                         [0 rgb 0]
>                         [1 rgb 1]
>                     }
>                     scale RWorld_Sun_Radius
>                 }
>             }
>         }
>     }
> }

rgbt ? the t is for transmit, 1 would go for 100% transmission

Have you tried an homogeneous media ?

Any clue about the value of RWorl_Sun_Radius ?

Is material legit there ? (I would have expected texture & interior
alone), material was to transport them together with finish too.


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From: Alain
Subject: Re: Emissive object not showing up
Date: 6 Aug 2018 13:03:31
Message: <5b687f63$1@news.povray.org>
Le 18-08-06 à 11:18, Le_Forgeron a écrit :
> Le 06/08/2018 à 13:55, Mike Horvath a écrit :
>> I have created this object at the center of my scene, but it is not
>> visible. What mistakes have I made? Thanks.
>>
>> Mike
>>
>>
>> sphere
>> {
>>      0, RWorld_Sun_Radius
>>      hollow
>>      material
>>      {
>>          texture
>>          {
>>              pigment {rgbt 1}
>>          }
>>          interior
>>          {
>>              media
>>              {
>>                  emission 100000
>>                  density
>>                  {
>>                      spherical
>>                      density_map
>>                      {
>>                          [0 rgb 0]
>>                          [1 rgb 1]
>>                      }
>>                      scale RWorld_Sun_Radius
>>                  }
>>              }
>>          }
>>      }
>> }
> 
> rgbt ? the t is for transmit, 1 would go for 100% transmission
> 
> Have you tried an homogeneous media ?
> 
> Any clue about the value of RWorl_Sun_Radius ?
> 
> Is material legit there ? (I would have expected texture & interior
> alone), material was to transport them together with finish too.
> 
material is legit. Here, it really does nothing. It's only a wrapper to 
make it possible to have a texture and an interior bundled together the 
convenience.

The possible problem could be one of scale. If the scene contain 
elements in the single unit range and other in the 10e6+ range, things 
tend to break down.

What is the ratio between the length of the camera's location and 
RWorld_sun_radius ? Is the camera farther than 1000000 units from the 
origin ?

You may want to use a scale of over 1000 Km per unit. Even up to 10E6 Km 
per unit.


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From: Mike Horvath
Subject: Re: Emissive object not showing up
Date: 6 Aug 2018 13:43:57
Message: <5b6888dd$1@news.povray.org>
On 8/6/2018 1:03 PM, Alain wrote:
> The possible problem could be one of scale. If the scene contain 
> elements in the single unit range and other in the 10e6+ range, things 
> tend to break down.
> 
> What is the ratio between the length of the camera's location and 
> RWorld_sun_radius ? Is the camera farther than 1000000 units from the 
> origin ?
> 
> You may want to use a scale of over 1000 Km per unit. Even up to 10E6 Km 
> per unit.
> 

// 1 unit = 100 miles
#declare RWorld_Sun_Diameter = 10000;
#declare RWorld_Ring_Radius = 950000;
#declare RWorld_Camera_Distance = 10;
#declare RWorld_Camera_Scale = RWorld_Ring_Radius * 1.1;

I think it did have something to do with scale. The problem went away, 
but don't know how or why.

Here's the new version:

sphere
{
	0, RWorld_Sun_Radius
	hollow
	material
	{
		texture
		{
			pigment {rgbt 1}
		}
		interior
		{
			media
			{
				emission 10/RWorld_Sun_Radius
				density
				{
					spherical
					density_map
					{
						[0.0 rgb 0]
						[0.1 rgb RWorld_Light_Point_Color]
						[1.0 rgb RWorld_Light_Point_Color]
					}
					scale RWorld_Sun_Radius
				}
			}
		}
	}
}


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From: Thomas de Groot
Subject: Re: Emissive object not showing up
Date: 7 Aug 2018 02:39:10
Message: <5b693e8e$1@news.povray.org>
On 6-8-2018 19:43, Mike Horvath wrote:
> I think it did have something to do with scale. The problem went away, 
> but don't know how or why.
> 

That is probably true. To avoid confusion, I generally scale the 
container at the end, e.g.:

sphere {
   0, 1
   hollow
   material {
     texture {
       pigment {rgbt 1}
     }
     interior {
       media {
         emission 10/MyScale
         scattering 3/MyScale
         density {
           spherical
           density_map {MyMap}
         }
       }
     }
   }
   scale MyScale
}

-- 
Thomas


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