Is there a way to control the angle of a linear_sweep in a prism object?  in
AutoCAD this would be equivalent to an extrusion angle, where a 2-d group of
joined lines is extruded outward or inward according to a certain angle. .
.I feel sure POV has some way to accomodate this but I can't figure out how,
from the docs.



Mike Metheny
lon### [at] vtedu
http://loneshepherd.ml.org/

"When one's words are no better than silence, one should keep silent."

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On Tue, 2 Feb 1999 02:38:03 -0500, Mike Metheny <lon### [at] vtedu> wrote:
>Is there a way to control the angle of a linear_sweep in a prism object?  in
>AutoCAD this would be equivalent to an extrusion angle, where a 2-d group of
>joined lines is extruded outward or inward according to a certain angle. .
>.I feel sure POV has some way to accomodate this but I can't figure out how,
>from the docs.

There is no such thing available directly, but you can roll your own
by using a normal linear_sweep and transforming it by a shear matrix.
I'll leave the calculation of the requisite matrix to someone else,
though.  It's too early in the morning and I haven't had my caffeine
yet. :)

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Ron Parker wrote:
> 
> On Tue, 2 Feb 1999 02:38:03 -0500, Mike Metheny <lon### [at] vtedu> wrote:
> >Is there a way to control the angle of a linear_sweep in a prism object?  in
> >AutoCAD this would be equivalent to an extrusion angle, where a 2-d group of
> >joined lines is extruded outward or inward according to a certain angle. .
> >.I feel sure POV has some way to accomodate this but I can't figure out how,
> >from the docs.
> 
> There is no such thing available directly, but you can roll your own
> by using a normal linear_sweep and transforming it by a shear matrix.
> I'll leave the calculation of the requisite matrix to someone else,
> though.  It's too early in the morning and I haven't had my caffeine
> yet. :)

http://www.erols.com/vansickl/matrix.htm  :)

-- 
Ken Tyler

tyl### [at] pacbellnet

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On Tue, 02 Feb 1999 05:40:08 -0800, Ken <tyl### [at] pacbellnet> wrote:
>Ron Parker wrote:
>> I'll leave the calculation of the requisite matrix to someone else,
>> though.  It's too early in the morning and I haven't had my caffeine
>> yet. :)
>
>http://www.erols.com/vansickl/matrix.htm  :)

I was in fact originally going to write "I'll leave the calculation
of the requisite matrix to John VanSickle." but I changed my mind
at the last second.

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Have you experimented with the conic_sweep option? According to the docs, that
will shrink teh extrusion. I assume that it shrinks to zero... the docs arent'
clear or I can't read all of the sudden : )

Mike Metheny wrote:

> Is there a way to control the angle of a linear_sweep in a prism object?  in
> AutoCAD this would be equivalent to an extrusion angle, where a 2-d group of
> joined lines is extruded outward or inward according to a certain angle. .
> .I feel sure POV has some way to accomodate this but I can't figure out how,
> from the docs.
>
> Mike Metheny
> lon### [at] vtedu
> http://loneshepherd.ml.org/
>
> "When one's words are no better than silence, one should keep silent."

--
Josh English
eng### [at] spiritonecom
www.spiritone.com/~english

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