# Matrices ?

Greetings !

Can anyone please explain to me, preferably with as
little math and as much theory as possible , how
matrices work in terms of forms and dimensions and what's
the relevant mechanism ?

I mean, I used to program Star Trek spaceships for a computer
game I once made using matrices. But, nobody ever explained
to me how and why it works, those were just meaningless tables
with sprecific relevant operators to me. I also know the
I can hardly remember it now), but not how and why it works for geometrical forms in various dimensions and stuff.

Thanks !

Live long and prosper.

Guybrush Threepwood
OK so maybe this is a response for a restricted area of matices use but here goes.
I program in OpenGL and I think the other 3D programming stuff has the same principles. To make a 3D scene you have to use coordinate transformation. These transformations (translation, rotation, scaling) can be written as a linear sistem between the coordinates in the old reference system, and the coordinates in the new reference system. Any linear equation system can be expressed in a matriceal form. So this is one of the reasons you use matrices. Also basic matrix operations are easy to program.

STAii
Or, in other words ...
You can do all the world transformation without matrices, it is only that matrices is a convinient way to save points, data, and transformations.
(i learned that while trying to learn Direct3D)

plus
One of the most interesting things about matrices are than, due to the method of multiplication A * B is not necessarily the same as B * A.

Sting
One of the most interesting things about matrices are than, due to the method of multiplication A * B is not necessarily the same as B * A.

Yep, Matrix multiplication is noncommutative and I know some people who failed exams because of it (even though the teacher had mentioned many times).

Guybrush Threepwood
Originally posted by plus
One of the most interesting things about matrices are than, due to the method of multiplication A * B is not necessarily the same as B * A.

true, true...
that's why in OpenGL a rotation, followed by a translation doesn't have the same result as a translation followed by a rotation. To do that you have to make some matrix multiplication and since it's not commutative the results are dependent of the order in which you multiply.