Merge pull request #1078 from nmaslarinos/RhinoSurface_curvature_fix

Rhino surface curvature fix

Author: gonzalocasas

CHANGELOG.md

@@ -27,6 +27,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 * Based all gltf data classes on `BaseGLTFDataClass`
 * Fixed `Color.__get___` AttributeError.
+* Fixed  `RhinoSurface.curvature_at` not returning a Vector, but a Rhino SurfaceCurvature class object 
 * Fixed `cylinder_to_rhino` conversion to match `compas.geometry.Cylinder` location.
 * Changed identification of cylinder brep face to non-zero in `compas_rhino.conversions.cylinder.Cylinder`.
 * Changed linter to `black`.
@@ -35,6 +36,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * Fixed bug in `_core.tangent` where the Circle's Plane was accessed instead of the centre.
 * Fixed the `test_tangent` to work with a properly defined circle
 * `RhinoBrep` serialization works now with surface types other than NURBS.
+
 ### Removed
 
 

src/compas_rhino/geometry/surfaces/surface.py

@@ -260,11 +260,20 @@ def curvature_at(self, u, v):
 
         Returns
         -------
-        :class:`~compas.geometry.Vector`
+        tuple[[float, float, float], [float, float, float], float, [float, float, float], float, [float, float, float], float, float] | None
+            A tuple containing the point, normal vector, maximum principal curvature value, maximum principal curvature direction,
+            minimun principal curvature value, minimun principal curvature direction, gaussian curvature value and mean curvature
+            value for the point at UV. None at failure.
 
         """
-        vector = self.rhino_surface.CurvatureAt(u, v)
-        return vector_to_compas(vector)
+        surface_curvature = self.rhino_surface.CurvatureAt(u, v)
+        if surface_curvature:
+            point, normal, kappa_u, direction_u, kappa_v, direction_v, gaussian, mean = surface_curvature
+            cpoint = point_to_compas(point)
+            cnormal = vector_to_compas(normal)
+            cdirection_u = vector_to_compas(direction_u)
+            cdirection_v = vector_to_compas(direction_v)
+            return (cpoint, cnormal, kappa_u, cdirection_u, kappa_v, cdirection_v, gaussian, mean)
 
     def frame_at(self, u, v):
         """Compute the local frame at a point on the curve.