For Finding value of A , B , C , D
a1 = x2 - x1 NEW_LINE b1 = y2 - y1 NEW_LINE c1 = z2 - z1 NEW_LINE a2 = x3 - x1 NEW_LINE b2 = y3 - y1 NEW_LINE c2 = z3 - z1 NEW_LINE A = b1 * c2 - b2 * c1 NEW_LINE B = a2 * c1 - a1 * c2 NEW_LINE C = a1 * b2 - b1 * a2 NEW_LINE D = ( - A * x1 - B * y1 - C * z1 ) NEW_LINE