switched to another formulation of the algorithm which computes surface normal of triangle: this is necessary for inside/outside check

field.py

@@ -934,23 +934,20 @@ class Features3d:
     # @staticmethod
     # def ray_triangle_intersect(self):
 
-    def ray_triangle_intersect(r0,dr,v0,v1,v2):
+    def ray_triangle_intersect(R,dR,A,B,C): 
-        v0v1 = v1-v0
+        E1     = B-A
-        v0v2 = v2-v0
+        E2     = C-A
-        pvec = np.cross(dr,v0v2)
+        N      = np.cross(E1,E2)
-        det = np.dot(v0v1,pvec)
+        det    = -np.dot(dR,N)
-        if np.abs(det)<1e-6: 
+        invdet = 1.0/det
-            return float('-inf')
+        AO     = R-A
-        invDet = 1.0 / det
+        DAO    = np.cross(AO,dR)
-        tvec = r0-v0
+        # u,v,1-u-v are the barycentric coordinates of intersection
-        u = np.dot(tvec,pvec)*invDet
+        u      =  np.dot(E2,DAO)*invdet
-        if u<0 or u>1: 
+        v      = -np.dot(E1,DAO)*invdet
-            return float('-inf')
+        # Intersection point is R+t*dR
-        qvec = np.cross(tvec,v0v1)
+        t      =  np.dot(AO,N)*invdet
-        v = np.dot(dr,qvec)*invDet
+        return (t,t*np.dot(N,dR)) if (np.abs(det) >= 1e-6 and u >= 0.0 and v >= 0.0 and (u+v) <= 1.0) else None
-        if v<0 or u+v>1: 
-            return float('-inf')
-        return np.dot(v0v2,qvec)*invDet
 
     def clean_points(self,report=False):
         nfaces_ = self._faces.shape[0]