Is there a way with SOR and lathe objects to limit the sweep to an arc 
of x degrees, where 0 < x < 360 ? -- WITHOUT differencing of any kind?
--Thanks
MMW

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In article <3DE### [at] attnet>, Mark M Wilson <mrm### [at] attnet> 
wrote:

> Is there a way with SOR and lathe objects to limit the sweep to an arc 
> of x degrees, where 0 < x < 360 ? -- WITHOUT differencing of any kind?

Well, you could use intersections instead...not what you want, I think. 
There is no way to do that without some kind of CSG or clipped_by.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/

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It seems like it _should_ be possible, considering how verbally easy the 
idea is to convey -- not that there's necessarily a correlation between 
the way an idea is expressed in words rather than equations! :-)

Maybe a feature for a future version?

--Mark


Christopher James Huff wrote:

> In article <3DE### [at] attnet>, Mark M Wilson <mrm### [at] attnet> 
> wrote:
> 
> 
>>Is there a way with SOR and lathe objects to limit the sweep to an arc 
>>of x degrees, where 0 < x < 360 ? -- WITHOUT differencing of any kind?
>>
> 
> Well, you could use intersections instead...not what you want, I think. 
> There is no way to do that without some kind of CSG or clipped_by.
> 
>

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In article <3DE### [at] attnet>, Mark M Wilson <mrm### [at] attnet> 
wrote:

> It seems like it _should_ be possible, considering how verbally easy the 
> idea is to convey -- not that there's necessarily a correlation between 
> the way an idea is expressed in words rather than equations! :-)
> 
> Maybe a feature for a future version?

It would be very easy to do, and maybe it will someday be 
implemented...but there is already an easy way to do it, using CSG or 
clipped_by, and it is a very special-purpose feature, so there probably 
isn't much interest.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/

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> It seems like it _should_ be possible, considering how verbally easy the
> idea is to convey -- not that there's necessarily a correlation between
> the way an idea is expressed in words rather than equations! :-)


The math behind it would be exactly the same as the math behind a CSG.

Why can't you use a CSG?

 - Slime
[ http://www.slimeland.com/ ]

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Since you had replied to my earlier posting about efficiency of CSG op's 
and bounding, you may have gathered that I'm "on a mission" to root out 
inefficiently coded CSG's, so I suppose I'm a little overzealous now in 
trying to find the most efficient ways of describing some of my scene 
elements. :-)
--MMW

Christopher James Huff wrote:


> 
> It would be very easy to do, and maybe it will someday be 
> implemented...but there is already an easy way to do it, using CSG or 
> clipped_by, and it is a very special-purpose feature, so there probably 
> isn't much interest.
> 
>

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I've nothing against CSG's; see my reply to CJH's posting (12-04-02, 
2:38 pm) on this thread.
--MMW

Slime wrote:


> Why can't you use a CSG?
> 
>  - Slime
> [ http://www.slimeland.com/ ]
> 
> 
>

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In article <3dee7287$1@news.povray.org>, "Slime" <slm### [at] slimelandcom> 
wrote:

> The math behind it would be exactly the same as the math behind a CSG.

Not really. An intersection or difference with 2 planes does quite a bit 
more than necessary for this, there are a lot of possible optimizations 
that could save some processing power. It is too little for too much of 
a special case to get anyone excited about it though...

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/

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"Mark M Wilson" <mrm### [at] attnet> wrote in message
news:3DE### [at] attnet...

>  I'm "on a mission" to root out inefficiently coded CSG's,
>  so I suppose I'm a little overzealous now in
> trying to find the most efficient ways of describing some of my scene
> elements. :-)
> --MMW

Then code what you can as a mesh approximation, and stop top posting. A
partial lathe mesh would be simple. I'm sure that some have done it, and
there is likely an example somewhere in p.b.s-f.

 -Shay

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What's "top posting?"  Whatever it is, it seems to really bother you!
Mind your tone.

Shay wrote:
> and stop top posting.  
> A partial lathe mesh would be simple.

Sorry, not for this newbie. ;-)

--Mark

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