Affine transforms - matrix algebra

[Kirill.Prazdnikov]

Hi Pavel,

>     public Affine(double[] matrix)
>         // accepts arrays of length 6, 12 and 16.
>         // In case of 16 members the last four numbers must be 0, 0, 0, 1
>         // throws IllegalArgument if the above conditions are not met 

What is the point of setting 4x4 matrix of the last row must be 0,0,0,1 ?
Should we remove 4x4 case at all ?

Thanks