Subject:
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Re: Line in the Sand
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Newsgroups:
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lugnet.cad.dev
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Date:
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Thu, 21 Oct 1999 01:00:39 GMT
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Viewed:
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1429 times
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Steve Bliss wrote in message <380e2b8e.12563517@lugnet.com>...
> 0 INVERT
>
> The INVERT meta-statement is a flag, indicating to the renderer that the
> following subfile reference has been intentionally inverted. If the next
> command-line is not a subfile reference, the INVERT is ignored.
>
> The INVERT flag is required in addition to the actual inversion, which
> occurs within the subfile command's transformation matrix.
An orientation matrix doesn't contain enough information to invert an
asymmetrical part; if you assume it does, this would result in a part with a
mirrored shape.
I propose that (1) INVERT be explicitly used instead of relying on negative
determinants, and (2) no matrix should ever have a negative determinant.
I don't know how many asymmetrical subparts there are, if any, so I don't
know if this is a relevant point or not.
-Gary
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Message has 1 Reply:
 | | Re: Line in the Sand
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| Gary Williams wrote in message ... (...) a (...) Well, what I meant to say is: Matrices with negative determinants may be used for mirroring a part, BUT the matrix should never be assumed to perform the actual inversion. If a matrix has a negative (...) (25 years ago, 21-Oct-99, to lugnet.cad.dev)
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Message is in Reply To:
| | Line in the Sand
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| OK, we've been discussing how to best extend the LDraw language to allow rendering engines to do backface-culling. We've got a pretty good agreement on most of what is needed. I think it would be productive, at this point, to work from a complete (...) (25 years ago, 20-Oct-99, to lugnet.cad.dev)
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