Subject:
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Re: Assembled parts, ~ and categories
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Newsgroups:
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lugnet.cad
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Date:
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Thu, 19 Nov 2009 20:10:03 GMT
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Viewed:
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9896 times
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In lugnet.cad, Sergio Reano wrote:
> > > requirement: http://www.ldraw.org/Article398.html).
>
> > > Hi,
> > > I read the above article and is OK, but many parts do not follow these
> > > requirements:
> > > for example part 71427C01.DAT distributed as official is named as assembly but
> > > contains the whole part definition inside with no references to any subparts but
> > > parts\P parts.
> > >
> > > In my personal opinion, from a programmer point of view, it could be a good
> > > practice to correctly code as assembly at least those parts that allow
> > > reciprocal movement in between them.
> > > For example a switch has a lever that moves while the base is static; a motor
> > > has an axle that rotate while the rest of the model is static.
> > >
> > > Other assembly should be multicolored parts (with the exclusion of patterned
> > > parts), since sometime these color can change.
> > >
> > > One more question: what does the suffixes "Dxx" and "Txx" stand for?
> > >
> > > regards...
> > >
> > > Sergio
> >
> > Please understand that the LDraw Parts Library is over 12 years old and
> > standards evolve over time. Things that were done in 1999, when 71427c01.dat was
> > created, wouldn't necessarily be done the same way now.
> >
> > *dNN.dat files are parts with stickers applied
> > *tNN.dat files are non-standard, and the only representative in the official is
> > in fact a ~Moved to (i.e re-direct) file .
> >
> > Chris
>
> I can understand the problem of aged parts, but, again from a programmer
> approach, I have to manage both "old" and "new" parts, so it will be very
> helpful if all parts can follow the same coding and naming standard.
>
> Please, consider the following example to understand what kind of problem I get:
> when I open a part, if it not an assembly I load all its graphics definition in
> the same memory storage since the whole parts moves. If it is an assembly,
> instead, I will load each "subpart" in different storage since one or more of
> them can move while other doesn't.
>
> If something is wrong then it could happen that some mechanism wont move or the
> whole part move (like in the motor example) and so the whole model will move
> since the motor chassis is "connected" to the rest of the model.
>
> If someone can correct the old parts, I can build and send the list of parts
> needing fixes.
>
> Sergio
Maybe you are trying to interpret too much from the naming convention. A
composite part (*cNN.dat) isn't necessarily comprised of parts that can move
relative to each other, It might just be made of two or more separately moulded
elements that are connected in a fixed configuration. Even if the separate
elements are moveable, there is no assurance that the rotation origon can be
deduced. So I think you have some big challenges here.
One solution might be to extend the metadata in the parts files, or include
separate "connection" information in the library in some other form. This has
been talked about before as an "LDraw Connections Database" project.
Please be careful not to misuse the term "subpart". That has a semantic meaning
in LDraw that does not mean "constituent part". The term is used to refer to a
separate file of re-used lines and surfaces, that is rarely, if ever, a closed
solid.
If you have analysed the library to identify which composite parts are not built
of parts, then please post it so that authors can work on bringing the library
up to the current conventions. Or maybe you could even take in some of that work
yourself?
Chris
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Message is in Reply To:
 | | Re: Assembled parts, ~ and categories
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| (...) I can understand the problem of aged parts, but, again from a programmer approach, I have to manage both "old" and "new" parts, so it will be very helpful if all parts can follow the same coding and naming standard. Please, consider the (...) (14 years ago, 19-Nov-09, to lugnet.cad)
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