Subject:
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Re: The use of type 5 lines for smoothing of objects.
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Newsgroups:
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lugnet.cad.dev
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Date:
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Fri, 17 May 2002 17:00:37 GMT
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Viewed:
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658 times
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In lugnet.cad.dev, Martijn Zwaal writes:
> I somewhat disagree with that. I do averaging at Dat file level and you can
> see that it works for cylinders. There should be no difference between
> connections of cylinder segments and sphere segments. If you inspect the 1/8
> sphere primitive with ML-Cad you can see that the control points of the
> optional lines are too far away form the primitive. If you extrapolate the
> sphere those points should lie on the sphere. They should be the same as the
> other control points but mirrored in the symmetry planes. You can also see
> that there are 31 optional lines in the file, but there are 30 edges. The
> 11th and the 30th are on the same edge I think. So the primitive needs to be
> fixed.
I guess I misunderstood your normal calculation. I thought you were basing
it on the normals of the the faces, not the normals formed by the type 5
lines and their control points. Using the control points makes sense,
except for one problem.
The problem is that the sphere primitive is actually correct. There was a
discussion about it a couple of weeks ago (that I started), and it was
determined that the sphere primitive's current setup is correct:
http://news.lugnet.com/cad/dev/?n=7169
I also posted a summary in this post (which is hopefully intelligable):
http://news.lugnet.com/cad/dat/parts/?n=3630
The reason the lines are like they are is that they produce a correct
silhouette when joined to more sphere segments, while also working when
joining a hemisphere to a cylinder. One other fallout of this is that the
cylinder primitives will likely be updated. (In fact, I believe that the
quarter cylinder already has been.)
--Travis Cobbs (tcobbs@REMOVE.halibut.com)
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Message is in Reply To:
 | | Re: The use of type 5 lines for smoothing of objects.
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| (...) normal (...) the (...) I somewhat disagree with that. I do averaging at Dat file level and you can see that it works for cylinders. There should be no difference between connections of cylinder segments and sphere segments. If you inspect the (...) (22 years ago, 17-May-02, to lugnet.cad.dev)
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