I am currently learning about game engines, and for the engine math, there are functions called GetXAxis, GetYAxis, and GetZAxis that returned the X, Y and Z axes for a matrix. These functions return the x, y and z components of the first three rows of the 4x4 matrix as a normalized Vector3. The actual functions are simple enough, but I am having trouble conceptually understanding what exactly the axes of a matrix are. Are they the forward, left, and up vectors of a transformation?