Re: pfDCS question

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John Rohlf (jrohlf++at++tubes)
Thu, 21 Oct 93 09:23:06 -0700

>> How do pfDCS calls affect each other? For example:
>>
>> pfDCS *dcs;
>>
>> pfDCSMat (dcs, some_matrix);
>> pfDCSRot (dcs, h, p, r);
>>
>> How about the reverse case?
>>
>> pfDCSRot (dcs, h, p, r);
>> pfDCSMat (dcs, some_matrix);
>
>I'm not sure if anyone answered this. The principal is
>one of replacement rather than concatentation. pfDCSMat
>"replaces" the entire 4x4 matrix. pfDCSRot replaces the
>rotational component of the matrix, preserving the
>existing scale or translation.
>

Also, the resulting DCS matrix is:

        M = S * R * T

i.e. - first you scale, then rotate, then translate

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