POV-Ray : Newsgroups : povray.bugreports : Is sphere_sweep known to be troublesome? Server Time
16 Jun 2024 11:02:31 EDT (-0400)
  Is sphere_sweep known to be troublesome? (Message 21 to 28 of 28)  
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From: Woody
Subject: Re: Is sphere_sweep known to be troublesome?
Date: 28 Mar 2010 01:40:03
Message: <web.4baeea5d2e5cb7c2876671bb0@news.povray.org>
Almost forgot.

Is this something that can be fixed in the future version or the next beta?


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From: Thorsten Froehlich
Subject: Re: Is sphere_sweep known to be troublesome?
Date: 28 Mar 2010 04:33:38
Message: <4baf1462$1@news.povray.org>
On 28.03.10 07:25, Woody wrote:
> Sorry for joining the conversation late. I only saw the thread after making the
> post at
>
> http://news.povray.org/web.4baed21667547a80876671bb0%40news.povray.org
>
> It appears ot be of the same problem.

No, that code uses a linear spline for which bounding works.

	Thorsten


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From: clipka
Subject: Re: Is sphere_sweep known to be troublesome?
Date: 28 Mar 2010 09:43:16
Message: <4baf5cf4@news.povray.org>
Am 28.03.2010 10:33, schrieb Thorsten Froehlich:
> On 28.03.10 07:25, Woody wrote:
>> Sorry for joining the conversation late. I only saw the thread after
>> making the
>> post at
>>
>> http://news.povray.org/web.4baed21667547a80876671bb0%40news.povray.org
>>
>> It appears ot be of the same problem.
>
> No, that code uses a linear spline for which bounding works.

Given that the bug reported by the OP has two components - garbled 
geometry /and/ a missing bounding box - I'd rather say yes, as far as 
the garbled geometry is concerned.


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From: Woody
Subject: Re: Is sphere_sweep known to be troublesome?
Date: 28 Mar 2010 10:40:01
Message: <web.4baf697d2e5cb7c2c41e4df50@news.povray.org>
Thorsten Froehlich <tho### [at] trfde> wrote:
> On 28.03.10 07:25, Woody wrote:
> > Sorry for joining the conversation late. I only saw the thread after making the
> > post at
> >
> > http://news.povray.org/web.4baed21667547a80876671bb0%40news.povray.org
> >
> > It appears ot be of the same problem.
>
> No, that code uses a linear spline for which bounding works.
>
>  Thorsten

I'm assuming when you refer to bounding you are referring to the specific
bounding mentioned in the documentation at
http://www.povray.org/documentation/view/3.6.1/323/

When doesn't this work?
For what type of splines?
I'm having trouble choosing a bounding box, or size and position, that gets rid
of these unwanted effects.

Any suggestions?


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From: Thorsten Froehlich
Subject: Re: Is sphere_sweep known to be troublesome?
Date: 28 Mar 2010 12:01:17
Message: <4baf7d4d$1@news.povray.org>
On 28.03.10 15:43, clipka wrote:
> Am 28.03.2010 10:33, schrieb Thorsten Froehlich:
>> On 28.03.10 07:25, Woody wrote:
>>> Sorry for joining the conversation late. I only saw the thread after
>>> making the
>>> post at
>>>
>>> http://news.povray.org/web.4baed21667547a80876671bb0%40news.povray.org
>>>
>>> It appears ot be of the same problem.
>>
>> No, that code uses a linear spline for which bounding works.
>
> Given that the bug reported by the OP has two components - garbled
> geometry /and/ a missing bounding box - I'd rather say yes, as far as
> the garbled geometry is concerned.

The geometry problems are the result of the bounding going wrong.

	Thorsten


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From: clipka
Subject: Re: Is sphere_sweep known to be troublesome?
Date: 28 Mar 2010 13:36:54
Message: <4baf93b6$1@news.povray.org>
Am 28.03.2010 18:01, schrieb Thorsten Froehlich:

> The geometry problems are the result of the bounding going wrong.
>
> Thorsten

No, definitely not - geometry code *MUST NOT* rely on any undesired 
surfaces being eliminated by bounding - if only because rotating the 
object may grow the bounding box.


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From: Thorsten Froehlich
Subject: Re: Is sphere_sweep known to be troublesome?
Date: 28 Mar 2010 18:06:55
Message: <4bafd2ff$1@news.povray.org>
On 28.03.10 19:36, clipka wrote:
>> The geometry problems are the result of the bounding going wrong.
>>
>> Thorsten
>
> No, definitely not - geometry code *MUST NOT* rely on any undesired
> surfaces being eliminated by bounding - if only because rotating the
> object may grow the bounding box.

I think there is some miscommunication: I am not saying that the bounding 
and the object depend on each other in any unusual way. I am just saying 
that for certain cases with cubic splines the bounding will be too small.

	Thorsten


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From: clipka
Subject: Re: Is sphere_sweep known to be troublesome?
Date: 28 Mar 2010 19:16:13
Message: <4bafe33d$1@news.povray.org>
Am 29.03.2010 00:06, schrieb Thorsten Froehlich:

> I think there is some miscommunication: I am not saying that the
> bounding and the object depend on each other in any unusual way. I am
> just saying that for certain cases with cubic splines the bounding will
> be too small.

Well, that's what we /will/ see once the bounding has been 
"quasi-fixed". But obviously it's not what we're seeing in the OP's 
scenario.


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