Dose anyone know how to scale a 2D vector about an arbitrary axis? Like the vector (10, 10) scaled about the axes (1, 0) by 2 = (20, 10), only I need to be able to scale it on any axis, not just the x or y. This should be a simple problem, but I can’t figure out how to do it. Thanks for any help.

I think you can solve your problem by first rotating your vector by an angle A, then scaling, then rotating back by -A. You can find the value of A by doing some trig/geometry; determine how much you''d need to rotate the xy axes to make them equivalent to your other axes. Tell me if you want some more information.

Suppose you want to scale vector v on the axis a by a factor k

(a is normalized)

Project v on a :
v = (a*v)*a + (v-(a*v)*a)
Then scale the part colinear to a
newv = k*(a*v)*a + (v-(a*v)*a)
You''re done