Sascha Ledinsky wrote:

> andrel wrote:
> 
>> The way I do it is as follows:
>> For both representations I compute the values at the 16
>> points (0,0),(1/3,0),(2/3,0),(1,0),(0,1/3),(1/3,1/3),...(1,1)
>> as a function of the input parameters. This wil give a 16 by
>> 16 matrix.
> 
> 
> 16 x 16 ?
you have 16 points and 16 parameters.
for the bezier the 16 control points and for the
hermite 4 points, 4 x 2 first order derivatives
and 4 second order derivatives.

Therefore: you start with 16 values and do a matrix
multiplication to get 16 other values. So it must
be a 16 by 16 matrix (and if it was not square you
could not invert it).

The 'interpolation' is independent (and the same) for the
x, y, and z coordinates.

Perhaps I should add that I am a bit lazy and have not
done the inversion by hand. I used a program to do
it for me.

	Andrel

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