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I'm not sure if this has been discussed before, but I discovered a problem with the use of type 5 lines at the edge of primitives. The basic problem is that there is no way for the primitive to know which direction any attached polygons are going to (...) (23 years ago, 4-May-02, to lugnet.cad.dev)
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| | Re: Type 5 lines at the edge of primitives
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(...) I'm not sure if I understand this properly - if the second "test" point is down the line where the cylinder joint (between two rects) would be if it was attached to a cylinder, won't that work? It'll mean the same line may occasionally be (...) (23 years ago, 5-May-02, to lugnet.cad.dev)
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| | Re: Type 5 lines at the edge of primitives
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(...) Hmm... Good point; I hadn't thought of that. But I'll have to check to be sure (it's hard to visualize). The way I currently have my sphere, the joins between the segments are always drawn either twice or not at all. If this does work, though, (...) (23 years ago, 5-May-02, to lugnet.cad.dev)
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| | Re: Type 5 lines at the edge of primitives
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(...) There was a discussion on this very issue in cad.dat.parts about 2 months ago. This one includes a link to a picture. (URL) don't think it was completely resolved though, as fixing it probably requires changing quite a few primitives and/or (...) (23 years ago, 5-May-02, to lugnet.cad.dev)
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| | Re: Type 5 lines at the edge of primitives
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(...) Well, I did as you suggested, and it solved the problem without introducing any new ones. I was also able to then visualize why it worked on a continuing sphere once I had it working. --Travis Cobbs (tcobbs@REMOVE.halibut.com) (23 years ago, 5-May-02, to lugnet.cad.dev)
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| | Re: Type 5 lines at the edge of primitives
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(...) Cool! Glad I could help! And after looking at the discussion Don linked to, I'm wondering if a similar thing could be done for type 5s on cylinder edges - make the second test point on the plane where a rectangle would be if it was butted up (...) (23 years ago, 6-May-02, to lugnet.cad.dev)
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| | Re: Type 5 lines at the edge of primitives
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(...) Yeah; I actually posted a response to that thread suggesting just this. (...) Well, it's only a problem if you don't add another type 5 line to the edge. And I agree that it's probably rare. --Travis Cobbs (23 years ago, 6-May-02, to lugnet.cad.dev)
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| | Re: Type 5 lines at the edge of primitives
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(...) Wow! This is so cool! These cooperating type 5 control points give us both first order continuity between the cylinder and the tangent plane, AND 2nd order continuity between adjacent cylinder parts. All with just a few small changes to a (...) (23 years ago, 6-May-02, to lugnet.cad.dev, lugnet.cad.dat.parts)
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| | Re: Type 5 lines at the edge of primitives [DAT]
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(...) Here is a model that demonstrates some of the problems with placing type 5 lines at the edge of the cylinder primitive. 0 1 16 0 0 0 10 0 0 0 10 0 0 0 10 1-4cyli.dat 1 16 0 0 20 10 0 0 0 10 0 0 0 0 -10 1-4cyli.dat 1 16 -20 0 20 10 0 0 0 10 0 0 (...) (23 years ago, 7-May-02, to lugnet.cad.dev)
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| | Re: Type 5 lines at the edge of primitives [DAT]
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(...) lines (...) And then there is matching a sphere with a torus Which is demonstrated with this file. 0 1 16 0 0 0 78 0 0 0 -78 0 0 0 78 1-8sphe.dat 1 16 0 0 0 90 0 0 0 90 0 0 0 90 t04i1333.dat 0 (23 years ago, 7-May-02, to lugnet.cad.dev)
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| | Re: Type 5 lines at the edge of primitives
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(...) I'm not following the problem with this one. Then again, I'm not sure where lines are supposed to be, and where they aren't--the construct is a bit abstract. (...) Hmm. The only way to avoid this problem is to not include the edge lines in the (...) (23 years ago, 7-May-02, to lugnet.cad.dev)
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| | Re: Type 5 lines at the edge of primitives [DAT]
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(...) There are too many numbers in the 2nd cylinder line. Cut and paste error? Give this one a spin. I think what he's trying to show is the type 5 line where the 2 quarter cylinders meet. 0 1 16 0 0 0 10 0 0 0 10 0 0 0 10 1-4cyli.dat 1 16 0 0 20 0 (...) (23 years ago, 7-May-02, to lugnet.cad.dev)
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