Subject:
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Overlapping polygons etc
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Newsgroups:
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lugnet.cad
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Date:
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Tue, 5 Aug 2003 13:05:18 GMT
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Viewed:
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542 times
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Hi all,
I'm currently working on http://www.peeron.com/inv/parts/30518
Firstly, if there's anyone else working on this please let me know, cos I'd
rather not ;)
But in case there isn't, I have a few questions:
1. Is there an "official" policy on overlapping & intersecting polygons? I have
(so far) included several in this part, as there are many cylinders
intersecting vertical planes etc, and avoiding the overlaps would take heaps
longer and produce *many* more polygons. I realise it may cause problems with
rendering the parts transparently, but is the extra work required to "do it
right" worth it in this case?
2. Should primitives be used where they aren't exactly right, but close enough?
There's a couple of situations with this part:
a) cylinder (stud) meets horizontal plane, but plane doesnt intersect
completely, the 3-4edge primitive is very close to providing the correct
intersection line, but it's a tiny bit too big, should I use it or manually do
the intersection, which would mean some renderers which substitute the stud may
not render very well.
b) Open wall ends of 2-4cyli touch outside wall of part - some renderers may
show vertical lines on outside wall. However in this case, the cylinder butts up
against the bottom of a stud2a, so if I manually do the cylinder, renderers that
substitute the stud may look strange with the un-substituted cylinder below it.
3. Approximations - The "slots" along the side of this part are slightly more
than 8LDU high and slightly more than 10LDU deep. However the 1x4 brick with
similar slots (http://www.peeron.com/inv/parts/2653) approximates to these
sizes, I guess I should too?
I've uploaded what I've done so far, as my explanations are probably not all
that clear. I was gonna just finish it & submit to the parts tracker, but I
figured there's so many questions, and I've taken quite a few shortcuts, it's
probably better to get opinions first.
http://www.brickshelf.com/gallery/RoscoHead/cad/30518.dat
I like to make parts as "correct" as possible, but if thats at the expense of
many extra polygons or possibility of bad rendering, it makes the decision
harder.
Thanks for any ideas
ROSCO
PS: I intend to work on http://www.peeron.com/inv/parts/30517 next.
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Message has 1 Reply:
 | | Re: Overlapping polygons etc
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| (...) My feeling on the matter is that while overlapping is not wrong, it should be avoided. I know from personal experience how time comsuming this can be. (...) In this case I'd say inline the primitive and trim (...) The problem is that the (...) (21 years ago, 5-Aug-03, to lugnet.cad)
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