Subject:
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Re: Primitive tolerances
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Newsgroups:
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lugnet.cad.dev
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Date:
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Thu, 20 Nov 2003 15:47:49 GMT
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Viewed:
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1743 times
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In lugnet.cad.dev, Paul Easter wrote:
> Can someone tell me what kind of accuracy tolerances we should be working within
> when it comes to scalable primitives?
>
> http://www.ldraw.org/cgi-bin/ptdetail.cgi?f=p/48/4-4ring3.dat
>
> I have placed a hold vote on this ring. Most all the numbers are within .0002.
> Is that acceptable or should the numbers be corrected. Can someone else give
> this part a close look over?
>
> dat file / prim-gen
> .3916 -> .3915
> .5221 -> .522
> .7765 -> .7764
> 1.0353 -> 1.0352
> 2.7716 -> 2.7717
> 2.8978 -> 2.8977
> 2.9743 -> 2.9742
> 3.6955 -> 3.6956
> 3.8637 -> 3.8636
> 3.9658 -> 3.9656
> I stopped tracking numbers at this point. There may be more that vary.
>
> I have been comparing this part to what "my" primitive generator says. I need to
> know if my primitive generator is giving us the correct numbers or not.
>
> Also see this thread for some reference information.
> http://news.lugnet.com/cad/?n=10209
>
> Paul
Generally parts only need to be authored to 3 decimal places. We decided on 4
DPs for the scalable primitives so that they could be scaled x10 without
degrading the quality of the part.
One could argue that p/48 primitves should be coded with more DPs since they
might be scaled more than x10.
So I would recommend that they do use 4 DPs, and use the algorithm that
multiplies the already rounded value from p/48/1-4disc,.
Chris
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Message is in Reply To:
 | | Primitive tolerances
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| Can someone tell me what kind of accuracy tolerances we should be working within when it comes to scalable primitives? (URL) have placed a hold vote on this ring. Most all the numbers are within .0002. Is that acceptable or should the numbers be (...) (21 years ago, 19-Nov-03, to lugnet.cad.dev)
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