POV-Ray : Newsgroups : povray.newusers : Skybox Issue Server Time
28 Jul 2024 18:15:33 EDT (-0400)
  Skybox Issue (Message 1 to 8 of 8)  
From: Simon
Subject: Skybox Issue
Date: 10 Oct 2007 15:04:23
Message: <470d2237$1@news.povray.org>
I've posted an image in p.b.i

Short version: I've got some images to use for a skybox, 112.5 degree 
viewing angle on the images and they should all match up perfectly.

I've only got the sides not the top and bottomin place but I can already see 
that the images don't join smoothly. I've set ambient 0 diffuse 1

I believe I need to stop light being effected by the angle of incidence, 
unless someone else can point out the obvious?

Would someone please kick me in the right direction?


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From: Zeger Knaepen
Subject: Re: Skybox Issue
Date: 10 Oct 2007 15:26:30
Message: <470d2766$1@news.povray.org>
"Simon" <povray@*NOSPAM*SOWare.co.uk> wrote in message 
news:470d2237$1@news.povray.org...
> I've posted an image in p.b.i
>
> Short version: I've got some images to use for a skybox, 112.5 degree 
> viewing angle on the images and they should all match up perfectly.
>
> I've only got the sides not the top and bottomin place but I can already 
> see that the images don't join smoothly. I've set ambient 0 diffuse 1

try the opposite: ambient 1 diffuse 0

cu!
-- 
#macro G(b,e)b+(e-b)*C/50#end#macro _(b,e,k,l)#local C=0;#while(C<50)
sphere{G(b,e)+3*z.1pigment{rgb G(k,l)}finish{ambient 1}}#local C=C+1;
#end#end _(y-x,y,x,x+y)_(y,-x-y,x+y,y)_(-x-y,-y,y,y+z)_(-y,y,y+z,x+y)
_(0x+y.5+y/2x)_(0x-y.5+y/2x)            // ZK http://www.povplace.com


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From: Simon
Subject: Re: Skybox Issue
Date: 10 Oct 2007 15:33:29
Message: <470d2909$1@news.povray.org>
"Zeger Knaepen" <zeg### [at] povplacecom> wrote in message 
news:470d2766$1@news.povray.org...
> "Simon" <povray@*NOSPAM*SOWare.co.uk> wrote in message 
> news:470d2237$1@news.povray.org...
>> I've posted an image in p.b.i
>>
>> Short version: I've got some images to use for a skybox, 112.5 degree 
>> viewing angle on the images and they should all match up perfectly.
>>
>> I've only got the sides not the top and bottomin place but I can already 
>> see that the images don't join smoothly. I've set ambient 0 diffuse 1
>
> try the opposite: ambient 1 diffuse 0
>
> cu!
> -- 
> #macro G(b,e)b+(e-b)*C/50#end#macro _(b,e,k,l)#local C=0;#while(C<50)
> sphere{G(b,e)+3*z.1pigment{rgb G(k,l)}finish{ambient 1}}#local C=C+1;
> #end#end _(y-x,y,x,x+y)_(y,-x-y,x+y,y)_(-x-y,-y,y,y+z)_(-y,y,y+z,x+y)
> _(0x+y.5+y/2x)_(0x-y.5+y/2x)            // ZK http://www.povplace.com
>

Thanks for the reply - you're quite right - I'm having a slow day :)

Having tried that, however, it's still the same. (For your ref, I have a 
rgb1 light source at the origin - I used it when placing walls and never 
removed it, hence the fact the image I posted wasn't black)


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From: Simon
Subject: Re: Skybox Issue
Date: 10 Oct 2007 15:35:31
Message: <470d2983$1@news.povray.org>
Hmmm there's something strange going on here. With ambient 0 diffuse 0, I 
can still see the box (although it's darker). Would it help if I posted the 
code?


"Zeger Knaepen" <zeg### [at] povplacecom> wrote in message 
news:470d2766$1@news.povray.org...
> "Simon" <povray@*NOSPAM*SOWare.co.uk> wrote in message 
> news:470d2237$1@news.povray.org...
>> I've posted an image in p.b.i
>>
>> Short version: I've got some images to use for a skybox, 112.5 degree 
>> viewing angle on the images and they should all match up perfectly.
>>
>> I've only got the sides not the top and bottomin place but I can already 
>> see that the images don't join smoothly. I've set ambient 0 diffuse 1
>
> try the opposite: ambient 1 diffuse 0
>
> cu!
> -- 
> #macro G(b,e)b+(e-b)*C/50#end#macro _(b,e,k,l)#local C=0;#while(C<50)
> sphere{G(b,e)+3*z.1pigment{rgb G(k,l)}finish{ambient 1}}#local C=C+1;
> #end#end _(y-x,y,x,x+y)_(y,-x-y,x+y,y)_(-x-y,-y,y,y+z)_(-y,y,y+z,x+y)
> _(0x+y.5+y/2x)_(0x-y.5+y/2x)            // ZK http://www.povplace.com
>


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From: Samuel Benge
Subject: Re: Skybox Issue
Date: 10 Oct 2007 17:14:12
Message: <470d40a4$1@news.povray.org>
Simon wrote:
> Hmmm there's something strange going on here. With ambient 0 diffuse 0, I 
> can still see the box (although it's darker). Would it help if I posted the 
> code?

Simon,

Are the images PNG files? If so, try using a different format. PNGs 
store gamma and alpha information, both of which can give unexpected 
results down the line.

Does your scene have fog? Is the skybox 'hollow'? If you are still 
seeing the box even with ambient 0 diffuse 0, then fog may be affecting 
your scene.

How did you create the images? Are you interested in trying something 
new? Rune's Illusion Include file lets you render a backdrop and place 
it into an existing scene (onto an object such as a skybox). It will 
work great if the camera does not move.

Link:
http://runevision.com/show.asp?id=96

Beyond that, make sure that ambient 1 and diffuse 0 are the *only* 
finish attributes in the box's texture.

Sam


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From: Simon
Subject: Re: Skybox Issue
Date: 10 Oct 2007 17:52:18
Message: <470d4992@news.povray.org>
thanks for the idea, I'll have a look at Rune's site. Unfortunately, I do 
want the camera to move. I have however, solved that problem:

What you all failed to account for was my stupidity:

 I rendered the skybox images in Bryce and failed to unlink the sun and the 
camera. The upshot? images with mis-matched light levels when joined (but 
perfectly matching borders).

Sorry for the hassle.

Having said that, the image on the skysphere seems very "faded". Is there 
any way I can make it more vibrant?

Sorry again and thanks for any further help

-Simon


"Samuel Benge" <stb### [at] THIShotmailcom> wrote in message 
news:470d40a4$1@news.povray.org...
> Simon wrote:
>> Hmmm there's something strange going on here. With ambient 0 diffuse 0, I 
>> can still see the box (although it's darker). Would it help if I posted 
>> the code?
>
> Simon,
>
> Are the images PNG files? If so, try using a different format. PNGs store 
> gamma and alpha information, both of which can give unexpected results 
> down the line.
>
> Does your scene have fog? Is the skybox 'hollow'? If you are still seeing 
> the box even with ambient 0 diffuse 0, then fog may be affecting your 
> scene.
>
> How did you create the images? Are you interested in trying something new? 
> Rune's Illusion Include file lets you render a backdrop and place it into 
> an existing scene (onto an object such as a skybox). It will work great if 
> the camera does not move.
>
> Link:
> http://runevision.com/show.asp?id=96
>
> Beyond that, make sure that ambient 1 and diffuse 0 are the *only* finish 
> attributes in the box's texture.
>
> Sam


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From: Simon
Subject: Re: Skybox Issue
Date: 10 Oct 2007 18:01:09
Message: <470d4ba5$1@news.povray.org>
Oh and no fog and also, for your ref, I'm creating the box out of 6 
infinitely thin cubes

"Samuel Benge" <stb### [at] THIShotmailcom> wrote in message 
news:470d40a4$1@news.povray.org...
> Simon wrote:
>> Hmmm there's something strange going on here. With ambient 0 diffuse 0, I 
>> can still see the box (although it's darker). Would it help if I posted 
>> the code?
>
> Simon,
>
> Are the images PNG files? If so, try using a different format. PNGs store 
> gamma and alpha information, both of which can give unexpected results 
> down the line.
>
> Does your scene have fog? Is the skybox 'hollow'? If you are still seeing 
> the box even with ambient 0 diffuse 0, then fog may be affecting your 
> scene.
>
> How did you create the images? Are you interested in trying something new? 
> Rune's Illusion Include file lets you render a backdrop and place it into 
> an existing scene (onto an object such as a skybox). It will work great if 
> the camera does not move.
>
> Link:
> http://runevision.com/show.asp?id=96
>
> Beyond that, make sure that ambient 1 and diffuse 0 are the *only* finish 
> attributes in the box's texture.
>
> Sam


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From: Thomas de Groot
Subject: Re: Skybox Issue
Date: 11 Oct 2007 07:26:39
Message: <470e086f$1@news.povray.org>
"Simon" <povray@*NOSPAM*SOWare.co.uk> schreef in bericht 
news:470d4992@news.povray.org...
>
> Having said that, the image on the skysphere seems very "faded". Is there 
> any way I can make it more vibrant?
>

When using image_maps, I often use a diffuse of 0.7 or 0.8 to correct 
exactly that.

Thomas


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