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Subject: 
Re: CW/CCW, vertex sequence, co-planar, convex, (115kB)
Newsgroups: 
lugnet.cad.dev
Date: 
Thu, 30 Sep 1999 16:28:48 GMT
Viewed: 
678 times
  
John VanZwieten wrote in message ...
Your idea for handling two instances of the same primitive would work.
Another, probably better, way would be to use mirroring to change the
CW/CCW-ness of the primitive to match the desired direction.  For a • primitive
like 2-4cyli.dat, you'd have to mirror and rotate the primitive to change • the
CW-ness and still have the primitive function the same.

The key as I see it would be to automate this process, probably with your • ray
tracing idea.  Doing it by hand would be a real drag.


A hypothetical batch dat fixer program could examine the primitives first
and flag the ones that were not closed volumes, since those would be the
only ones that would need to have their reference orientation matrices
mirrored and rotated.

I think there could be problems if some of those non-closed primitives are
asymmetrical.

-Gary



Message has 1 Reply:
  Re: CW/CCW, vertex sequence, co-planar, convex, (115kB)
 
(...) It wouldn't matter if they were closed-volume or not--they could still be turned inside out accidently. And an inside-out closed-volume primitive wouldn't do anybody any good. (...) Why? Steve (25 years ago, 1-Oct-99, to lugnet.cad.dev)

Message is in Reply To:
  Re: CW/CCW, vertex sequence, co-planar, convex, (115kB)
 
Gary Williams <graywolf@pcpros.net> wrote in message news:FIvo77.F2B@lugnet.com... (...) In the case I'm talking about, 1 primitive is used in 1 instance to be both an outer face and an inner face. In this case, you'd have to fix it manually by (...) (25 years ago, 30-Sep-99, to lugnet.cad.dev)

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