POV-Ray : Newsgroups : povray.newusers : Surface of revolution not rendering properly. Server Time
2 Jul 2024 11:38:53 EDT (-0400)
  Surface of revolution not rendering properly. (Message 1 to 4 of 4)  
From: D103
Subject: Surface of revolution not rendering properly.
Date: 9 Nov 2010 19:00:01
Message: <web.4cd9df12e4822cf2e5f70da10@news.povray.org>
I was recently trying to create a tap using a surface of revolution for its
base. When rendered, the image was covered with black areas.

After commenting out all the objects, I found that it was the sor that was
causing the problem.
When replaced with a lathe, the problem disappeared.

I was just wondering if anyone can tell me why the sor did this.

D103


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From: Warp
Subject: Re: Surface of revolution not rendering properly.
Date: 10 Nov 2010 10:24:53
Message: <4cdab945@news.povray.org>
D103 <nomail@nomail> wrote:
> I was recently trying to create a tap using a surface of revolution for its
> base. When rendered, the image was covered with black areas.

  Did you try adding the keyword 'sturm' to the sor?

-- 
                                                          - Warp


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From: D103
Subject: Re: Surface of revolution not rendering properly.
Date: 12 Nov 2010 21:20:00
Message: <web.4cddf41febf466994d0343c00@news.povray.org>
Warp <war### [at] tagpovrayorg> wrote:
> D103 <nomail@nomail> wrote:
> > I was recently trying to create a tap using a surface of revolution for its
> > base. When rendered, the image was covered with black areas.
>
>   Did you try adding the keyword 'sturm' to the sor?
>
> --
>                                                           - Warp

Yes, but nothing changed.

A couple of other things I noticed, the sor rendered correctly with radiosity
set to a count of 1, but this made the lighting very blotchy.

Also, in the scene I am using a scale where one pov-unit is equal to a metre, so
this makes the sor really quite small, with it's greatest radius being 0.025
units. Could this be causing the problem?

D103


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From: Alain
Subject: Re: Surface of revolution not rendering properly.
Date: 12 Nov 2010 21:46:06
Message: <4cddfbee@news.povray.org>


> Yes, but nothing changed.
>
> A couple of other things I noticed, the sor rendered correctly with radiosity
> set to a count of 1, but this made the lighting very blotchy.
>
> Also, in the scene I am using a scale where one pov-unit is equal to a metre, so
> this makes the sor really quite small, with it's greatest radius being 0.025
> units. Could this be causing the problem?
>
> D103
>
>

It's indeed a prety small radius and can result in FP acuracy problems. 
It can easily cause some problem, especialy if you have some large 
values elsewhere in your scene, like something at 1 000 000 unit away. 
This result in a 40 000 000 to 1 relative dimentions.

You may try making the sor about 100 times larger in it's definition and 
scale it down 100 times. In some cases that can help.



Alain


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