An algorithm for intersection of arbitrary polygons in space

        public static string Mypf_function () {var lee = 0;            float D1 = 0, d2 = 0; var ret = "Multipatch does not intersect!!            ";            Space two multipatch p1[0] = new Polytopepoint (0, 0, 1);            P1[1] = new Polytopepoint (0, 0, 2);            P1[2] = new Polytopepoint (2, 2, 2);            P1[3] = new Polytopepoint (2, 2, 1);            P2[0] = new Polytopepoint (2, 1, 0);            P2[1] = new Polytopepoint (0, 1, 0);            P2[2] = new Polytopepoint (0, 1, 3);            P2[3] = new Polytopepoint (2, 1, 3); var x1 = p1[1]. X-p1[0].            X var y1 = p1[1]. Y-p1[0].            Y var z1 = p1[1]. Z-p1[0].            Z var x2 = p1[2]. X-p1[0].            X var y2 = p1[2]. Y-p1[0].            Y var z2 = p1[2]. Z-p1[0].                         Z var a1 = P2[1]. X-p2[0].            X var B1 = p2[1]. Y-p2[0].            Y var C1 = p2[1]. Z-p2[0].            Z var a2 = p2[2]. X-p2[0].             X var b2 = p2[2]. Y-p2[0].            Y var C2 = P2[2]. Z-p2[0].            Z            Two-way vector var n1 = new Polytopepoint (y1 * z2-z1 * y2, z1 * x2-x1 * z2, x1 * y2-y1 * x2);            var n2 = new Polytopepoint (B1 * c2-c1 * B2, C1 * A2-A1 * c2, A1 * B2-B1 * A2);            The signed distance of the first plane point to the second plane var a=new float[4]; for (var i = 0; i < 4; i++) {A[i] = n1. X * (P2[i]. X-p1[0]. X) + N1. Y * (P2[i]. Y-p1[0]. Y) + N1. Z * (P2[i]. Z-p1[0].            Z);            }//Disjoint condition if (a[0] * A[1] > 0 && a[0] * A[2] > 0 && a[0] * A[3] > 0)            {return ret; }//Coplanar if (Math.Abs (a[0]) < 0.00000000000001 && Math.Abs (a[1]) < 0.00000000000001 &amp                ;& Math.Abs (a[2]) < 0.00000000000001 && Math.Abs (a[3]) < 0.00000000000001) { ret = "Two Multipatch coplanar!"                ";            return ret;  }//First plane point to the first plane of the signed distance var B = new Float[4];          for (var i = 0; i < 4; i++) {b[i] = n2. X * (P1[i]. X-p2[0]. X) + n2. Y * (P1[i]. Y-p2[0]. Y) + n2. Z * (P1[i]. Z-p2[0].            Z);                    } for (var i = 0, i < 3; i++) {for (var j = 0; J < 3; J + +) {                        On the second plane of the clamping edge on the existence of conditions if (a[i] * a[i + 1] < 0) {                            The existence condition if (b[j] * b[j + 1] < 0) for the clamping edge on the first plane { var L = p1[j + 1]. X-P1[J].                            X var m = p1[j + 1]. Y-P1[J].                            Y var n = p1[j + 1]. Z-P1[J].                             Z var o = p2[i + 1]. X-p2[i].                            X var p = p2[i + 1]. Y-p2[i].                            Y var q = p2[i + 1]. Z-p2[i].                            Z          On one or two sides, take a clip edge to the vector NT vertical var nt=new polytopepoint (M*q-n*p,n*o-l*q,l*p-m*o);                  if (Lee = = 0) {d1 = nt. X* (P1[i]. X-P2[J]. X) + NT. y* (P1[i]. Y-P2[J]. Y) + NT. z* (P1[i]. Z-P2[J].                                Z);                            lee++; } else {d2 = NT. X * (P1[i]. X-P2[J]. X) + NT. Y * (P1[i]. Y-P2[J]. Y) + NT. Z * (P1[i]. Z-P2[J].                            Z); }//Polygon intersection condition if (D1 * D2 < 0 | |    (Math.Abs (D1) < 0.00000000000001 && Math.Abs (D2) < 0.00000000000001)) A slight flaw puts the condition wide enough to intersect the intersection of {ret = "two Multipatch" as long as the cable intersects the Multipatch!                                  ";                            return ret;            }}}}} ret = "Exception";        return ret; }

　　

An algorithm for intersection of arbitrary polygons in space