[Bf-committers] Proposal to Change Mathutils Vectors

[Paul Melis]

On 12/07/2011 07:25 AM, Peter K.H. Gragert wrote:
> if A and B are matrices most of the cases A * B != B * A
> Matrix multiplication is NOT commutative.
> 
> Math:
> Matrix * Vector (Vector should be a column vector)
> Vector * Matrix (Vector should be a row vector)
> 
> Could be done differently in Blender as it was from time to time, but then
> it is not Math ..

>>> v = Vector([1,2,3])
>>> w = Vector([4,5,6])
>>> v*w
32.0

>>> w*v
32.0

Vector * Vector also *just works*, completely disregarding the fact that
one vector should be 1xN and the other Nx1 if you were to follow strict
math conventions. 3D math in computer graphics has always been very
pragmatic.

Regards,
Paul