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 CAD / Development / Organizations / LDraw / 1923
1922  |  1924
Subject: 
Re: [Parts Tracker] More BFC Primitives
Newsgroups: 
lugnet.cad.dev.org.ldraw
Date: 
Mon, 8 Apr 2002 16:30:52 GMT
Viewed: 
444 times
  
In lugnet.cad.dev.org.ldraw, Kyle McDonald wrote:

First I'd like to suggest that *if* there is a 'standard' winding for
LDRAW parts that it be CW. I make this suggestion based on the following:
[snip]

OK, sounds reasonable to me.

(Though once the winding in the files is well documented, it should
  be trivial to programatically convert the files to a 'standard'
  winding. No?)

Yes.

Second, on the subject of the 0 BFC INVERTNEXT meta command, I'd like
to make sure I understand the suggested usage, and possibly make an
argument for a change (If I understand it correctly)
[snip more]

You understand the usage correctly.  Except there's no special tie
between a 'mirroring' subfile reference and the INVERTNEXT command.
Authors won't explicitly use one to 'undo' the other.

My problem with this method is that now I have to examine the
matrix watching for mirroring that I need to undo. Up until
now I've been able to pass the matrix from the .DAT file straight
on to the rendering engine, without examining the contents.
I'd prefer to be able to continue to do that.

The problem here is that non-inverting mirroring is very commonplace in
LDraw parts, and in some places it can't be avoided (except by
inlining).  For example, most parts that appear in a right- and
left-hand pair (wings, exhaust pipes, etc) are set up so that only one
file has the full DAT code -- the other file of the pair just has a
mirrored reference to its partner.

Doing a parse-time test on each subfile reference matrix (to determine
if the matrix is mirroring or not) should not be a big hit on
performance.

Steve



Message has 1 Reply:
  Re: [Parts Tracker] More BFC Primitives
 
Steve Bliss wrote: > In lugnet.cad.dev.org.ldraw, Kyle McDonald wrote: > [snip more] > > You understand the usage correctly. Except there's no special tie > between a 'mirroring' subfile reference and the INVERTNEXT command. > Authors won't (...) (22 years ago, 9-Apr-02, to lugnet.cad.dev.org.ldraw)

Message is in Reply To:
  Re: [Parts Tracker] More BFC Primitives
 
Hello, Comments below... Travis Cobbs wrote: > In lugnet.cad.dev.org.ldraw, Steve Bliss writes: > >>In lugnet.cad.dev.org.ldraw, Tony Hafner writes: >> >>>In lugnet.cad.dev.org.ldraw, Steve Bliss writes: >>> >>>>>Um... Not to stir the pot or (...) (22 years ago, 6-Apr-02, to lugnet.cad.dev.org.ldraw)

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