Nurbs Birail update 2.

refs #3884.

nodes/surface/nurbs_birail.py

@@ -106,10 +106,26 @@ def update_sockets(self, context):
         default = False,
         update = updateNode)
 
+    rotate_options = [
+            ('PATHS_AVG', "Paths average", "Rotate profile(s), trying to make it perpendicular to both paths", 0),
+            ('FROM_PATH1', "Perpendicular to Path 1", "Rotate profile(s), trying to make it perpendicular to the first path", 1),
+            ('FROM_PATH2', "Perpendicular to Path 2", "Rotate profile(s), trying to make it perpendicular to the second path", 2),
+            ('FROM_PROFILE', "By profile", "Try to use initial rotation of profile curve(s)", 3)
+        ]
+
+    profile_rotation : EnumProperty(
+            name = "Profile rotation",
+            description = "Defines how profile curves should be rotated",
+            items = rotate_options,
+            default = 'PATHS_AVG',
+            update = updateNode)
+
     def draw_buttons(self, context, layout):
         layout.prop(self, 'nurbs_implementation', text='')
         layout.prop(self, "scale_uniform")
         layout.prop(self, "auto_rotate_profiles")
+        layout.label(text="Profile rotation:")
+        layout.prop(self, "profile_rotation", text='')
         layout.prop(self, "explicit_v")
 
     def draw_buttons_ext(self, context, layout):
@@ -187,6 +203,7 @@ def process(self):
                                     metric = self.metric,
                                     scale_uniform = self.scale_uniform,
                                     auto_rotate = self.auto_rotate_profiles,
+                                    use_tangents = self.profile_rotation,
                                     implementation = self.nurbs_implementation
                                 )
                 new_surfaces.append(surface)

utils/curve/nurbs_algorithms.py

@@ -122,13 +122,18 @@ def concatenate_nurbs_curves(curves):
             raise Exception(f"Can't append curve #{i+1}: {e}")
     return result
 
-def nurbs_curve_to_xoy(curve):
+def nurbs_curve_to_xoy(curve, target_normal=None):
     cpts = curve.get_control_points()
 
     approx = linear_approximation(cpts)
     plane = approx.most_similar_plane()
     normal = plane.normal
 
+    if target_normal is not None:
+        a = np.dot(normal, target_normal)
+        if a > 0:
+            normal = -normal
+
     xx = cpts[-1] - cpts[0]
     xx /= np.linalg.norm(xx)
 
@@ -139,4 +144,19 @@ def nurbs_curve_to_xoy(curve):
     center = approx.center
     new_cpts = np.array([matrix @ (cpt - center) for cpt in cpts])
     return curve.copy(control_points = new_cpts)
-
+
+def nurbs_curve_matrix(curve):
+    cpts = curve.get_control_points()
+
+    approx = linear_approximation(cpts)
+    plane = approx.most_similar_plane()
+    normal = plane.normal
+
+    xx = cpts[-1] - cpts[0]
+    xx /= np.linalg.norm(xx)
+
+    yy = np.cross(normal, xx)
+
+    matrix = np.stack((xx, yy, normal)).T
+    return matrix
+

utils/surface/nurbs.py

@@ -8,7 +8,7 @@
         nurbs_divide, from_homogenous
     )
 from sverchok.utils.curve import knotvector as sv_knotvector
-from sverchok.utils.curve.nurbs_algorithms import interpolate_nurbs_curve, unify_curves, nurbs_curve_to_xoy
+from sverchok.utils.curve.nurbs_algorithms import interpolate_nurbs_curve, unify_curves, nurbs_curve_to_xoy, nurbs_curve_matrix
 from sverchok.utils.curve.algorithms import unify_curves_degree, SvCurveFrameCalculator
 from sverchok.utils.surface.core import UnsupportedSurfaceTypeException
 from sverchok.utils.surface import SvSurface, SurfaceCurvatureCalculator, SurfaceDerivativesData
@@ -910,6 +910,7 @@ def nurbs_birail(path1, path2, profiles,
         degree_v = None, metric = 'DISTANCE',
         scale_uniform = True,
         auto_rotate = False,
+        use_tangents = 'PATHS_AVG',
         implementation = SvNurbsSurface.NATIVE):
     """
     NURBS BiRail.
@@ -931,6 +932,8 @@ def nurbs_birail(path1, path2, profiles,
     * scale_uniform: If True, profile curves will be scaled along all axes
         uniformly; if False, they will be scaled only along one axis, in order to
         fill space between two path curves.
+    * auto_rotate: if False, the profile curves are supposed to lie in XOY plane.
+        Otherwise, try to figure out their rotation automatically.
     * implementation: surface implementation
 
     output: tuple:
@@ -992,16 +995,34 @@ def nurbs_birail(path1, path2, profiles,
     points1 = path1.evaluate_array(ts1)
     points2 = path2.evaluate_array(ts2)
 
-    tangents1 = path1.tangent_array(ts1)
-    tangents2 = path2.tangent_array(ts2)
-    tangents = 0.5 * (tangents1 + tangents2)
-    tangents /= np.linalg.norm(tangents, axis=1, keepdims=True)
+    orig_profiles = profiles[:]
+
+    if use_tangents == 'PATHS_AVG':
+        tangents1 = path1.tangent_array(ts1)
+        tangents2 = path2.tangent_array(ts2)
+        tangents = 0.5 * (tangents1 + tangents2)
+        tangents /= np.linalg.norm(tangents, axis=1, keepdims=True)
+    elif use_tangents == 'FROM_PATH1':
+        tangents = path1.tangent_array(ts1)
+        tangents /= np.linalg.norm(tangents, axis=1, keepdims=True)
+    elif use_tangents == 'FROM_PATH2':
+        tangents = path2.tangent_array(ts2)
+        tangents /= np.linalg.norm(tangents, axis=1, keepdims=True)
+    elif use_tangents == 'FROM_PROFILE':
+        tangents = []
+        for profile in orig_profiles:
+            matrix = nurbs_curve_matrix(profile)
+            yy = matrix @ np.array([0, 0, -1])
+            yy /= np.linalg.norm(yy)
+            tangents.append(yy)
+        tangents = np.array(tangents)
 
     binormals = points2 - points1
     scales = np.linalg.norm(binormals, axis=1, keepdims=True)
     if scales.min() < 1e-6:
         raise Exception("Paths go too close")
     binormals /= scales
+
     normals = np.cross(tangents, binormals)
     normals /= np.linalg.norm(normals, axis=1, keepdims=True)
 
@@ -1014,9 +1035,11 @@ def nurbs_birail(path1, path2, profiles,
 
     scales = scales.flatten()
     placed_profiles = []
-    for pt1, pt2, profile, scale, matrix in zip(points1, points2, profiles, scales, matrices):
+    prev_normal = None
+    for pt1, pt2, profile, tangent, scale, matrix in zip(points1, points2, profiles, tangents, scales, matrices):
+
         if auto_rotate:
-            profile = nurbs_curve_to_xoy(profile)
+            profile = nurbs_curve_to_xoy(profile, tangent)
 
         t_min, t_max = profile.get_u_bounds()
         pr_start = profile.evaluate(t_min)