Subject:
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Re: Lego Brick Dimensions Changes?
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Newsgroups:
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lugnet.cad
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Date:
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Tue, 26 Nov 2002 18:50:17 GMT
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Viewed:
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407 times
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The LDraw standards for dimensions make up a self-consistent system, though
that system has some fundamental differences when compared to real-world bricks.
> Does the LDU dimensions used in LDraw correspond to any real units of
> measure and how accurate are those converted dimensions? Better yet if you
> actually have measured stuff out that would be great.
The general rule is that a plate is 1/8th of an inch, so one ldraw unit is
1/64th of an inch. But that's not quite dead on. I did some measurement
and calculation a while back. See this post for what I found:
http://news.lugnet.com/cad/?n=5284
For differences between various parts, LDraw doesn't have to consider
real-world physics. Plates in ldraw have essentially the same geometry as
bricks. But in the real world, plates have to flex more to bind with the
same force. Likewise, a 2x2 brick will have to flex more than a 2x8 brick.
LDraw also uses simplified geometry to make it easier to deal with. The two
most obvious examples are stud height and bottom tube outside diameter.
It's pretty trivial to demonstrate that a stud is taller than half of a
tile's thickness. And simple geometry tells us that there's no way the
outside of a bottom stud works out to an even number. What should these
numbers really be? I'm working on them for a rendering project, though I'm
not exactly spending a ton of time on it right now.
LDraw is a wonderful system for its intended purpose- generating
instructions. And you can make really neat images with it. But if you want
to model the parts themselves as realistically as possible, you have to
depart a bit from the standards.
--
Tony Hafner
www.hafhead.com
In lugnet.cad, Sun Yun writes:
> Has anyone taken the time to measure a standard 2x4 brick or plate in
> detail? More than just outer height width and length but inner wall
> thicknesses, cylinder diameters etc.
>
> I've been spending time working out the relationships and proportions of
> bricks and plates as they correspond from different axes(I hope that makes
> sense). As I was messing around I noticed differences between the wall
> thicknesses as well between various bricks, which made me wonder what the
> actual dimensions were. If your curious just pick up a 2x4 and a 2x8 and
> you should notice a difference in not only the design on the inner wall but
> different thicknesses as well.
>
> Does the LDU dimensions used in LDraw correspond to any real units of
> measure and how accurate are those converted dimensions? Better yet if you
> actually have measured stuff out that would be great.
>
> Any help would be much appreciated.
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Message has 1 Reply:
 | | Re: Lego Brick Dimensions Changes?
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| (...) This is one prime number relationship in the system. If cell spacing is 20 and stud radius is 6, then a diagonal distance between two studs is 20 * Sqrt(2) - 12, or about 16.28. This is the tube outside diameter. The inside diameter ought to (...) (22 years ago, 26-Nov-02, to lugnet.cad)
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Message is in Reply To:
| | Lego Brick Dimensions Changes?
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| Has anyone taken the time to measure a standard 2x4 brick or plate in detail? More than just outer height width and length but inner wall thicknesses, cylinder diameters etc. I've been spending time working out the relationships and proportions of (...) (22 years ago, 26-Nov-02, to lugnet.cad)
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