Subject:
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Re: Some Words To BFC
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Newsgroups:
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lugnet.cad.dev
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Date:
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Thu, 6 Apr 2000 06:59:37 GMT
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Viewed:
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2214 times
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In lugnet.cad.dev, Steve Bliss writes:
> In lugnet.cad.dev, Michael Lachmann wrote:
>
> > I warn everbody to put to much additional into BFC since I found out, that • the
> > BFC overhead is not to
> > underastimate. To much additional checks would cost drawing speed and • therefor
> > make BFCed file-drawing slower.
>
> What would you suggest simplifying or removing?
I would suggest to make the meta-commands for the renderer as simple as
possible and move all other corrections to external programs or functions.
I believe that what we have of BFC in MLCad for example is good enough to work
with BFCed parts.
>
> > As an example I take the matrix-repair statement:
> > Checking the matrix for bad definitions is easy, but then you have to find
> > out, which of the values is wrong, and correct it.
>
> How do you mean? What is a 'bad definition' in a matrix? Having a
> negative determinant? And what do you have to do to correct it? My
> understanding was that the rendering program could handle this problem
> by reversing which winding it was expecting.
There was this case mentioned where the determinant of a matrix is 0 and
therefor BFCing has to be disabled (do you remember :-)).
It would be easy for a program to find the wrong values and replace the right
one with 1. I'm not talking about matrixes as we had them in the past like
1 0 0 0 0 0 0 0 1 .... would be easy to correct ... but again we would loose
time.
I still like the idea of preprocessing parts for BFCing especially as I'm
currently working on preprocessed parts anyway. I will try to use them in order
to increase rendering time.
Just for them who like to know: Preprocessed parts will be a MLCad thing in the
first step, where the program generates binary dat files which will have a new
extension e.g. ppd. There are no sub-files within the parts and therefor
rendering should be much faster. At least this should apply to MLCad and I
think other creation programs.
This stuff might not be useful for viewer-only programs.
I'll let you know what happens with it.
Michael
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Message is in Reply To:
 | | Re: Some Words To BFC
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| (...) What would you suggest simplifying or removing? (...) How do you mean? What is a 'bad definition' in a matrix? Having a negative determinant? And what do you have to do to correct it? My understanding was that the rendering program could (...) (25 years ago, 6-Apr-00, to lugnet.cad.dev)
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