Subject:
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Re: Rotating a part?
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Newsgroups:
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lugnet.cad
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Date:
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Thu, 21 Jan 1999 20:28:28 GMT
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Viewed:
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764 times
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This seems designed to rotate points given an angle and a rotation axis.
I'm trying to determine what angle(s) to use given a line between two
points. Also, I'm not a programmer, so I'm basically stuck with formulas I
can use in a spreadsheet.
Perhaps being more specific will help. Each segment of the flexible hose is
a cylinder with a hemisphere sticking out the bottom end. The insertion
point is at the "apex" of the hemisphere. The cylinder is oriented around
the y axis. To look right, each segment should be oriented around a line
from its own insertion point to the insertion point of the next segment.
Using a beizier spline formula, I have calculated the insertion points of
all 50 segments of the hose. I have also used Linc's spreadsheet (and your
e-mail on the subject) to enable me to transform the part given angles of
rotation about x,y, and z axes. The "missing link" is that my initial
attempt to calculate how many degrees to rotate each segment (and on what
axes) was incorrect. At this point, it's more a math question than a
computer graphics question. Or, maybe I'm going about this the wrong way
and there is a way to transform the part directly based on it's insertion
point and the next insertion point.
-John Van
Steve Bliss wrote in message <36a76ead.7975214@lugnet.com>...
> On Thu, 21 Jan 1999 15:00:57 GMT, "John VanZwieten"
> <john_vanzwieten@msn.com> wrote:
>
> > L-cad is down, and I really would like help with this:
> >
> > I have point A (x,y,z) and point B (x',y',z'). I want to rotate a part
> > (with its insertion point at A) so that it is perpendicular to the line • AB.
> > How do I calculate the angles of rotation about each axis? Do I need to
> > rotate on three axes, or is two sufficient?
>
> Here's a better answer than the one I sent to L-CAD (which I assume is
> still in listserv limbo). This is a quote from the
> comp.graphics.algorithms FAQ. But first, info on where to get the
> complete FAQ:
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Message has 1 Reply:
 | | Re: Rotating a part?
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| Ah. You can't apply the solution given, because you need to find the axis of rotation. That axis is the vector which is normal to the vertical line through the current insertion point and the ending insertion point. There's probably also information (...) (25 years ago, 21-Jan-99, to lugnet.cad)
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Message is in Reply To:
| | Re: Rotating a part?
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| (...) Here's a better answer than the one I sent to L-CAD (which I assume is still in listserv limbo). This is a quote from the comp.graphics.algorithms FAQ. But first, info on where to get the complete FAQ: ===...=== Subject 0.03: How can I get (...) (25 years ago, 21-Jan-99, to lugnet.cad)
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