Question

I have a 4*4 matrix and a 3d vector.
I need to translate my vector by the matrix.

Not too much crazy maths notation please because I don’t understand it.

An example in something close to java would be fab!

Answer 1

It quite easy once you see it.

(New-3d-point) = Metrix-4x4 x (Old-3d-point)

means …

|x_new|   |a1 a2 a3 a4|   |x_old|
|y_new| = |b1 b2 b3 b4| x |y_old|
|z_new|   |c1 c2 c3 c4|   |z_old|
|  1  |   |d1 d2 d3 d4|   |  1  |

means …

x_new = a1*x_old + a2*y_old + a3*z_old + a4
y_new = b1*x_old + b2*y_old + b3*z_old + b4
z_new = c1*x_old + c2*y_old + c3*z_old + c4

d1-d4 are there to make ‘1’ so you don’t need to use it.

Hope this helps.