I am calculating the normal vector to a plane ax+by+cz+d=0
According to the book:
The normal vector N is often normalized to unit length because in that case the equation
d = N ⋅Q + D
gives the signed distance from the plane to an arbitrary point Q. If d = 0, then the point Q lies in the plane. If d > 0, we say that the point Q lies on the positive side of the plane since Q would be on the side in which the normal vector points.
How to get the N (Normal vector)? Thank you