Subject:
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Re: "Hold" placed on tyre (was Re: Tyre for this wheel, does it exist in the distro?
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Newsgroups:
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lugnet.cad.dat.parts
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Date:
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Mon, 13 May 2002 16:48:36 GMT
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Viewed:
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2335 times
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In lugnet.cad, Larry Pieniazek writes:
> Yes I got what I needed, thanks. However I voted "hold" on the part. The
> reasons I gave in the hold had to do with the sidewall bead width, plus I
> found another "flaw" which I need advice on. What's the right group to
> discuss? cad.dat.parts?
Based on the charter, cad.dat.parts would not be the right group (unless the
tyre had been posted to cad.dat.parts, and you posted a follow-up to that
posting). But there seems to be a need for group(s) for focus(s)ed
discussion of part files, and there aren't any better groups around...
> FUT set there because I think so.
>
> anyway... The number of segments used in the tyre to approximate a circular
> tyre rim (sidewall bead) does not match the number of segments used in the
> wheel that it mates with.
>
> This means that at extreme zoom you can see places where there is a gap
> between the wheel rim lip and the tyre sidwall bead, and other places where
> the tyre sidewall bead and the wheel rim overlap. Slightly and only visible
> at extreme mag.
>
> What is policy on this?
There isn't a policy on this - I don't think this has been brought up before.
> Is this a valid reason for a hold?
It *might* be. But I don't think it really can be, except in a sort of
minor way (bear with me, I'll try to make it clear).
> The tyre has the
> number of segments that it ought to because of the tread pattern it uses.
> The wheel has the number of segments that it does because it's built using
> primitives, i think. Changing the wheel to match the tyre would be hard (and
> if you rotated the tyre by a non segment number of degrees you 'd still have
> overlaps) Changing the tyre to match the wheel would be enve harder because
> it would mean you did not have a nice segment primitive, each segment would
> have to be done separately and you'd STILL have the overlap problem on
> rotation.
I think you've got the crux of it, here. Even if we make the tyre and wheel
mate nicely in the standard orientation, it will still be very easy to
'mismatch' them with a slight rotation. So, really, there is no perfect fix
for the problem.
However, approaching it from a slightly different direction...
The wheel and tyre should be modeled as 'round' surfaces. By definition,
the curved primitives are 'round'. So, if the wheel part is modeled with
primitives, then it's OK. Likewise, if the tyre is modeled with primitives,
then it's OK. But, like you said, the tyre is modelled from a 1/24 segment
subfile.
Probably the best solution would be to remove the inner bead from the 1/24
subfile, and replace it with regular primitives (or 48-segment primitives)
in the main part file.
> Believe it or not this is the first time I have ever used a tyre in a model.
> I bet this "problem" applies to many tyres... does it?
It could - I don't know, but I'll assume it does.
> Does this matter or should I release the hold? It's a nice tyre in all other
> respects.
You might try email Bill and see if he's willing to change the file at this
point. It doesn't make the file any more or less right, but it could impact
your willingness to give this one a passing review.
> Is there a FAQ entry about this?
Nope. Want to write one?
> (Steve I warned you I'd be asking dumb questions once I could review things!)
It's not a dumb question. Try harder next time.
Steve
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Message has 1 Reply:
 | | Suggest a group ...
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| (...) Snipped the rest and FUT to admin.suggestions. More on the actual issue later. I would like to suggest that a group (groups?) be created for focused discussion of parts files so that cad.dat.parts can return to being a group that has dat files (...) (22 years ago, 13-May-02, to lugnet.cad.dat.parts, lugnet.admin.suggestions)
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