# Normals

I know math by itself, but what I dont know is what math abstraction is applied where ?

For example, what can I do with normal vectors ?    What I can infer is, that by being normal, i.e. magnitude = 1, it doesnt matter the magnitude in multiplication (identity), i.e. it helps to set a direction for something, where magnitude is not considered. Whats that something ? Examples ?

By being slow for rotation, how can I convert Quaternions to matrices and what do we do in general in that case?

What math abstractions do we need to know in order to do what in 3D programming ?

I'm not really understanding what you're asking for, but is it an explanation about the usage of normals in 3d programming you want?

like this one: http://en.wikipedia.org/wiki/Surface_normal

sandstorm said:

I know math by itself, but what I don't know is what math abstraction is applied where ?

The good thing about an engine like jME is, that it hides the complex 3D math from you, so you can use more time to think about your games logic and stuff.
I wouldn't worry too much about Math, until you stumble upon a specific problem somewhere.

sandstorm said:

What math abstractions do we need to know in order to do what in 3D programming ?

I think its more important to know the common techniques used in 3D graphics than to know the detailed math behind it.

I think what you meant was normalized… (i.e. of size 1) instead of normal (as in, perpendicular to a surface).

On the quaternions thing… jME does not support the use of Matrices directly, so you would have to either modify the engine core or use quaternions for everything, which is not that bad at all anyways.