Subject:
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Re: Finding a rotation matrix for a triangle
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Newsgroups:
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lugnet.cad
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Date:
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Tue, 29 Nov 2005 14:02:15 GMT
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Viewed:
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1511 times
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In lugnet.cad, Niels Bugge wrote:
> In lugnet.cad, Timothy Gould wrote:
> > I think you are getting two things a little crossed here but I will try to
> > answer you questions.
>
> Heh, probably ;-)
>
> Well, perhaps I got the math part, and definition process a bit mixed up: I'd
> just like to have a program that, from a three coordinates on a plane, can
> give me a rotation vector+angle that I can enter in MLCad... And I'm a total
> hack when it comes to math: A perpendicular vector just seemed like the
> perfect starting point for a program that should give you an output that
> could help you place a primitive on the right side of a plane.
>
> But I'm afraid I'm in way over my head with the wikipedia formula: It looks
> like it will need (a lot of) modifications to give an output that can be used
> in MLCad (xyz_+ angle_). And the addition of the mystical t-thing...
>
> ...anyone?
>
> Anyways, thanks for the formula for the perpendicular vector Tim: I have this
> wierd feeling that I'm going to need it for something, althought I can't put
> my finger on it right now...
>
> Cheers NB
Hi Niels,
There isn't really a meaningful way to get an angle out of a plane defined by
three points. What would the angle mean? The xyz, angle formula in MLCad just
says rotate the vector angle degrees around the vector xyz but in the case of a
triangle, what would that angle be?
If you are thinking of a specific way of obtaining the angle from the triangle,
please let me know and I can work out the formla for you.
One thing that can be done is to find an orthogonal basis set which spans the
plane which might be useful. If this is of interest to you I can write some code
for it.
Tim
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Message has 1 Reply:
 | | Re: Finding a rotation matrix for a triangle
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| (...) The angle of the plane defined by the three points: I need to slap a primitive directly onto the triange with the correct angle. Now, if I should only slap this edge-primitive onto some rect-primitive, I should be able to copy the angle (...) (19 years ago, 5-Dec-05, to lugnet.cad, FTX)
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Message is in Reply To:
| | Re: Finding a rotation matrix for a triangle
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| (...) Heh, probably ;-) Well, perhaps I got the math part, and definition process a bit mixed up: I'd just like to have a program that, from a three coordinates on a plane, can give me a rotation vector+angle that I can enter in MLCad... And I'm a (...) (19 years ago, 29-Nov-05, to lugnet.cad, FTX)
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