Subject:
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Re: Question: polygons filling a t-shape
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Newsgroups:
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lugnet.cad
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Date:
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Thu, 4 Dec 2003 03:45:04 GMT
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Viewed:
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480 times
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In lugnet.cad, Travis Cobbs wrote:
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In lugnet.cad, Niels Karsdorp wrote:
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Hi,
I read somewhere (forgot where) that quads and triangles should not pass by
vertices, because this may cause gaps in some renderers.
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I suspect they will create artifacts in just about any renderer, but the
severity will vary from one to another.
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For L-shapes, the poligons should be created as on the right image:
But how should T-shapes (and H-shapes, too) be created?
(The black lines are edges, the red lines are seperators between polygons)
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The above looks fine. You could do it with one less LDraw primitive while
still preventing artifacts if you did it like so instead:
Note that all three shapes in the above diagram would be quads, with the
fourth point for quad number 2 being at the point the arrow points to. My
program LDView currently incorrectly removes that extra point, but I’ve
already updated the code to stop doing that, and the next release will act
correctly.
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Great diagrams, thanks!
But I thought that (rgarding quad 2 in the last diagram) collinear points were
considered an error by the checkers, so that when you submit your part to parts
tracker it would be flagged???
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Message has 2 Replies:
 | | Re: Question: polygons filling a t-shape
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| (...) I'm not sure if it does or not. After posting the previous post, I realized that I was mistaken about my alternate version being "ok". I just realized that it could result in the same rendering artifacts that using a triangle for polygon 2 (...) (21 years ago, 4-Dec-03, to lugnet.cad, FTX)
| | | Re: Question: polygons filling a t-shape
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| (...) Yes, L3P detects and warns about the collinear points of the quad. In the case of splitting the T why don't you just use triangles? The renderers do that anyway, but then you can take control of the splitting. I believe quads are mainly a (...) (21 years ago, 4-Dec-03, to lugnet.cad)
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Message is in Reply To:
| | Re: Question: polygons filling a t-shape
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| (...) I suspect they will create artifacts in just about any renderer, but the severity will vary from one to another. (...) The above looks fine. You could do it with one less LDraw primitive while still preventing artifacts if you did it like so (...) (21 years ago, 4-Dec-03, to lugnet.cad, FTX)
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