up

Gets the basis vector representing the Y-axis of the coordinate system after this matrix's transformation. This is commonly referred to as the "up" vector.

For a row-major matrix, this vector is extracted directly from the first three elements of the second row: (m10, m11, m12).

If the matrix includes scaling, this vector's length will reflect that scaling, and it is not guaranteed to be a unit vector. To get a pure direction, normalize this vector.