Plane equation Conversion
Converts a Plane equation from/to cartesian, normal and parametric form
• cartesian form : a.x+b.y+c.z+d = 0
• normal form: definined by a point M0 of the plane (x0 y0 z0) and a perpendicular vector to plane `\vecn` (u v w)
• parametric form : defined by a point M0 of the plane (x0 y0 z0) and two vector of the plane `\vece`(u v w) and `\vecf`(r s t). Plane equation is (p and q are two real numbers) :
x = x0+p*u+q*r
y = y0+p*v+q*s
z = z0+p*w+q*t