Subject:
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Re: Can someone explain the method to the madness...
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Newsgroups:
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lugnet.cad
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Date:
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Tue, 9 Mar 2004 15:46:11 GMT
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Viewed:
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1822 times
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In lugnet.cad, Orion Pobursky wrote:
> In lugnet.cad, Mike Thorn wrote:
> > Well, I don't know if it's madness or not, but it's driving {me} mad, at any
> > rate.
> >
> > Can some kind soul explain either or both of the following:
> >
> > 1) What is the conversion system for MLCAD units to POV units, when not using
> > LGEO?
>
> One to One
That is correct Orion.
> > 2) Why does L3P create matrices for the placement of elements instead of
> > using |translate|?
>
> Matrix is faster because a matrix defines rotation, translation, scaling, and
> skewing all in the same statement.
L3P uses matrix because a line type 1 already is a matrix.
It didn't occur to me to set the last three elements of the matrix as zeros
and printing them in a separate translate statement in stead.
Speed is only a parsing issue. Internally in PovRay all transformations
are multiplied together into one matrix.
> > I'm cracking my keyboard over my head trying to replace a |matrix| with a
> > |translate| so I can perform a clock animation on it, but I'm having
> > absolutely no success. Desperation drives one to ask many questions.
>
> You can translate without replacing the matrix. Here's a typical POV matrix:
>
> matrix <-1,0,0,0,1,0,0,0,-1,0,-56,30>
>
> The last 3 numbers are the object's postion (i.e. translation).
Yes, the equivalent is:
matrix <-1,0,0,0,1,0,0,0,-1, 0,0,0>
translate <0,-56,30>
/Lars
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Message is in Reply To:
 | | Re: Can someone explain the method to the madness...
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| (...) One to One (...) Matrix is faster because a matrix defines rotation, translation, scaling, and skewing all in the same statement. (...) You can translate without replacing the matrix. Here's a typical POV matrix: matrix (...) (23 years ago, 8-Mar-04, to lugnet.cad)
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