Subject:
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Re: Accuracy of curved surfaces
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Newsgroups:
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lugnet.cad
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Date:
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Wed, 7 Apr 2004 04:21:29 GMT
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Viewed:
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843 times
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In lugnet.cad, Niels Karsdorp wrote:
> I am working on 'Electric Train 12V Brick 2 x 4 with Power Pickup'
> (Step 8 in: http://library.brickshelf.com/scans/0000/0727/0727-03.html)
> This part contains some curved surfaces that cannot be done with primitives
> (very odd angles, like 41.112 degrees, 36.082 degrees and 21.786 degrees, so I
> have to create these using triangles, quads and conditional lines.
> My question now is: how accurate do I have to create these surfaces, ie. how
> many angles?
Generally, I create curved surfaces by using the appropriate primitives. Once I've
got the primitive sized to create the surface, I inline it and clip out anything that
falls outside of the desired surface. So I'd use the primitive to determine the
number of angles.
However, the number of segments to use probably depends more upon the radius of
curvature, rather than angles in degrees. Up to about radius 30LDU, I'd definitely
stick with the regular primitives, which have 16 segments per circle, or 1 segment =
22.5 degrees. Above radius 60LDU, I'd definitely use the 48-segment primitives (1
segment = 7.5 degrees). Between 30LDU and 60LDU radius, it's a judgement call. IMO.
Steve
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Message has 1 Reply:
 | | Re: Accuracy of curved surfaces
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| (...) I forgot to mention the radii, these are between 50 and 65 LDU. I first tried 11.25 degrees, this didn´t look round enough. Later I changed this to 3.75 degrees. Now I changed this back to 7.5 degrees, which looks good enough in L3Lab and (...) (20 years ago, 7-Apr-04, to lugnet.cad)
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Message is in Reply To:
| | Accuracy of curved surfaces
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| I have a parts-author question. I am working on 'Electric Train 12V Brick 2 x 4 with Power Pickup' (Step 8 in: (URL) part contains some curved surfaces that cannot be done with primitives (very odd angles, like 41.112 degrees, 36.082 degrees and (...) (21 years ago, 31-Mar-04, to lugnet.cad)
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