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 CAD / Development / 7822
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Subject: 
Re: Detemining Bad Vertex Sequence
Newsgroups: 
lugnet.cad.dev
Date: 
Thu, 12 Sep 2002 16:45:28 GMT
Viewed: 
2001 times
  
In lugnet.cad.dev, Don Heyse writes:
> In lugnet.cad.dev, Steve Bliss writes:
> > What would be especially good is if there was an option to test and flip
> > adjacent polygons.  Once the winding of one polygon is known, adjacent
> > polygons can be automatically wound correctly.
> 
> I'm not so sure this is completely true because we allow overlapping
> and intersecting polygons.  In fact, there is nothing which prevents
> a single polygon face from being partly on the outside and partly on
> the inside.  You can't automagically fix that without breaking up the
> polygon.

Right.  There are definitely situations in ldraw parts that won't fit the
nice all-polygons-in-a-mesh model.  That's why I said that auto-rewind
should be an 'option'.  Meaning, the user can turn it off.

Although for a part to be BFC compliant, it *can't* have any polygons that
are both inside and outside.  In this case, it wouldn't matter if the
program had auto-rewind or not - the user would have to break up the polygon
manually, then apply correct winding.

Steve



Message is in Reply To:
  Re: Detemining Bad Vertex Sequence
 
(...) I'm not so sure this is completely true because we allow overlapping and intersecting polygons. In fact, there is nothing which prevents a single polygon face from being partly on the outside and partly on the inside. You can't automagically (...) (24 years ago, 12-Sep-02, to lugnet.cad.dev)

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