Fix zero division errors for Ellipse curve.

utils/curve/primitives.py

@@ -512,10 +512,26 @@ def second_derivative_array(self, ts):
         return vs
 
     def to_nurbs(self, implementation=SvNurbsMaths.NATIVE):
-        scale = Matrix([[1,0,0], [0, self.b/self.a, 0], [0, 0, 1]]).to_4x4()
+        if self.a == 0 and self.b == 0:
+            coef_x = 0
+            coef_y = 0
+            radius = 0
+        elif self.a == 0:
+            coef_x = 0
+            coef_y = 1
+            radius = self.b
+        elif self.b == 0:
+            coef_x = 1
+            coef_y = 0
+            radius = self.a
+        else:
+            coef_x = 1
+            coef_y = self.b/self.a
+            radius = self.a
+        scale = Matrix([[coef_x,0,0], [0, coef_y, 0], [0, 0, 1]]).to_4x4()
         matrix = Matrix(self.matrix).to_4x4()
         matrix.translation = Vector(self.get_center())
-        circle = SvCircle(matrix = matrix @ scale, radius = self.a,
+        circle = SvCircle(matrix = matrix @ scale, radius = radius,
                     center = self.get_center())
         return circle.to_nurbs(implementation)
 

utils/geom.py

@@ -1501,6 +1501,8 @@ def c(self):
         """
         a = self.a
         b = self.b
+        if a < b:
+            raise Exception("Major semi-axis of the ellipse can not be smaller than minor semi-axis")
         return sqrt(a*a - b*b)
 
     @property

utils/math.py

@@ -334,6 +334,12 @@ def np_normalize_vectors(vecs):
     vecs[nonzero] = vecs[nonzero] / norms[nonzero][:,np.newaxis]
     return vecs
 
+def np_multiply_matrices_vectors(matrices, vectors):
+    vectors = vectors[np.newaxis]
+    vectors = np.transpose(vectors, axes=(1,2,0))
+    r = matrices @ vectors
+    return r[:,:,0]
+
 def weighted_center(verts, field=None):
     if field is None:
         return np.mean(verts, axis=0)