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Subject: 
Re: Modelling !
Newsgroups: 
lugnet.cad.dev
Date: 
Fri, 9 Jun 2000 19:59:19 GMT
Reply-To: 
rui.martins@link.NOMORESPAMpt
Viewed: 
2325 times
  
On Fri, 9 Jun 2000, Steve Bliss wrote:

> In lugnet.cad.dev, Rui Martins wrote:
> 
> > Has some of you may remember, I have modelled the super car (8880) wheels and
> > tires, but when I modeled it I used Metric measurements (millimeters).
> > 
> > I would Like to know if there is an approved standard for a convertion ratio,
> > between millimeters and Ldraw units ?
> > So that I can scale the modelled parts and have them corrected!
> 
> I believe the conversion is 0.4mm = 1 LDU.  At least, that's what I always
> use.

Thanks !

So, 1.00 mm = 2.5 LDU

> > I would also like to know when are we going to define orientation standards /
> > guidelines for when a part is created ?
> 
> Standards are already there.  They just aren't strictly enforced.  As I see
> it, there are two basic "orientation rules":

> 1. Do the same thing as other, similar parts which were previously modeled.
> 2. If there is inconsistency in the existing parts library, go with the
> majority or the senior parts.

I call this common sence, which I think everyone should use !

> If a part truly breaks new ground, and there aren't any sufficiently
> similar parts, then go with the following guidelines:

Are these your opinions only, or is assumed buy other people too ?
I agree with most of it !

> 1. If the part is symmetric along both horizontal dimensions, the wider
> dimension should go along the X-axis.
Check!

> 2. If the part is asymmetric along one horizontal dimension, that dimension
> should go along the Z-axis, with the front/tip of the part pointed toward
> Z-.
Check!

> 3. Center the part on X-Z.

Shouldn't we always center on the center of a stud or connection (like wheels)?
Not on Total X/Z size.

> 4. Generally, put the top of part (not including studs) at Y=0.
Check!

> 5. Rotating parts *may* be centered on the point of rotation.
Check !

Maybe this should be placed in http://www.ldraw.org somewhere, maybe open anew
section for modellers, like a getting started page, with rules and guidelines.

> > Since I have seen technic Axels(non-threaded/threaded), wheels, Wind Screens,
> > Windows, doors, etc...  with non matching orientations.
> > (example: Two wheels which have different rotation axis)
> > suppose you had diferent orientations for different bricks, that would be a
> > mess, so Why did this happen for the parts I mentioned before ?
> 
> Because we're all volunteers.

I know that !

what I meant was:
How did those parts get by us, without this beeing noticed ?

> > P.S. I know it is a huge task if we ever need to make all these parts have the
> > same orientation. We would probably have to make a program to correct our dat
> > files, when the parts were reoriented. Sigh..
> 
> Interesting thought.  If the program was programmed with all the version
> information of the parts (using the 0 Official L-CAD Update XXXXXXX line),
> it could be done.

I meant something along the lines of a program that would rotate/translate all
parts (which would be defined in a .CFG file or something) according to a
specific transformation matrix for each, and applied this to one of our personal
model files, correcting the parts, their references/placement.

See ya

Rui Martins



Message has 1 Reply:
  Re: Modelling !
 
(...) Some of this has come up in various discussions. I'm not sure if all of it has or not. (...) No, centering on a stud isn't necessary. Look at 3001.dat, the 2x4 brick. It is centered on X-Z, not on a stud. The same applies for all other (...) (26 years ago, 9-Jun-00, to lugnet.cad.dev)

Message is in Reply To:
  Re: Modelling !
 
(...) I believe the conversion is 0.4mm = 1 LDU. At least, that's what I always use. (...) Standards are already there. They just aren't strictly enforced. As I see it, there are two basic "orientation rules": 1. Do the same thing as other, similar (...) (26 years ago, 9-Jun-00, to lugnet.cad.dev)

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