Indication of positive and negative curvature values.

nodes/viz/viewer_draw_surface.py

@@ -213,26 +213,36 @@ class SvSurfaceViewerDrawNode(SverchCustomTreeNode, bpy.types.Node):
             update = updateNode)
 
     curvature_types = [
-        ('GAUSS', "Gauss", "Gauss curvature", 0),
-        ('MEAN', "Mean", "Mean curvature", 1),
+        ('GAUSS', "Gauss", "Gauss curvature - product of minimum and maximum curvature", 0),
+        ('MEAN', "Mean", "Mean curvature - average between minimum and maximum curvature", 1),
         ('MAX', "Maximum", "Maximum curvature", 2),
         ('MIN', "Minimum", "Minimum curvature", 3),
         ('DIFF', "Difference", "Difference between maximum and minimum curvature", 4)
     ]
 
     curvature_type : EnumProperty(
             name = "Curvature type",
+            description = "Type of surface curvature to be indicated by color",
             items = curvature_types,
             default = 'GAUSS',
             update = updateNode)
 
-    curvature_color: FloatVectorProperty(
-            name = "Curvature color",
+    curvature_max_color: FloatVectorProperty(
+            name = "Maximum curvature color",
+            description = "Color to be used to indicate positive curvature values",
             default = (0.9, 0.1, 0.0, 1.0),
             size = 4, min = 0.0, max = 1.0,
             subtype = 'COLOR',
             update = updateNode)
 
+    curvature_min_color: FloatVectorProperty(
+            name = "Minimum curvature color",
+            description = "Color to be used to indicate negative curvature values",
+            default = (0.0, 0.1, 0.9, 1.0),
+            size = 4, min = 0.0, max = 1.0,
+            subtype = 'COLOR',
+            update = updateNode)
+
     light_vector: FloatVectorProperty(
         name='Light Direction', subtype='DIRECTION', min=0, max=1, size=3,
         default=(0.2, 0.6, 0.4), update=updateNode)
@@ -278,10 +288,10 @@ def draw_buttons(self, context, layout):
 
         row = grid.row(align=True)
         row.prop(self, 'draw_curvature', icon='EVENT_C', text='')
-        row.prop(self, 'curvature_color', text='')
-        row.prop(self, 'curvature_type', text='')
-        #if self.draw_curvature:
-        #    grid.prop(self, 'curvature_type', text="Type")
+        row.prop(self, 'curvature_max_color', text='')
+        row.prop(self, 'curvature_min_color', text='')
+        if self.draw_curvature:
+            grid.prop(self, 'curvature_type', text="Type")
 
         row = layout.row(align=True)
         row.scale_y = 4.0 if self.prefs_over_sized_buttons else 1

utils/surface/bakery.py

@@ -123,30 +123,44 @@ def __init__(self, node, surface, resolution_u, resolution_v):
                 curvature_values = calc.mean()
             elif node.curvature_type == 'MAX':
                 c1, c2 = calc.values()
-                curvature_values = np.max((abs(c1), abs(c2)), axis=0)
+                #curvature_values = np.max((abs(c1), abs(c2)), axis=0)
+                curvature_values = np.max((c1, c2), axis=0)
             elif node.curvature_type == 'MIN':
                 c1, c2 = calc.values()
-                curvature_values = np.min((abs(c1), abs(c2)), axis=0)
+                #curvature_values = np.min((abs(c1), abs(c2)), axis=0)
+                curvature_values = np.min((c1, c2), axis=0)
             else: # DIFF
                 c1, c2 = calc.values()
-                m = np.min((abs(c1), abs(c2)), axis=0)
-                M = np.max((abs(c1), abs(c2)), axis=0)
+                m = np.min((c1, c2), axis=0)
+                M = np.max((c1, c2), axis=0)
+                #m = np.min((abs(c1), abs(c2)), axis=0)
+                #M = np.max((abs(c1), abs(c2)), axis=0)
                 curvature_values = M - m
 
             curvature_values[np.isnan(curvature_values)] = 0
             min_curvature = curvature_values.min()
             max_curvature = curvature_values.max()
+            surface_colors = np.zeros((resolution_u*resolution_v, 4))
+            surface_colors[:] = main_color
+            max_color = np.array(node.curvature_max_color)
+            min_color = np.array(node.curvature_min_color)
             if (max_curvature - min_curvature) < 1e-4:
-                surface_colors = np.empty((resolution_u*resolution_v, 4))
-                surface_colors[:] = main_color
+                curvature = (max_curvature + min_curvature)*0.5
+                if curvature > 0:
+                    surface_colors[:] = max_color
+                if curvature < 0:
+                    surface_colors[:] = min_color
             else:
-                c = (curvature_values - min_curvature) / (max_curvature - min_curvature)
-                print(f"C: min {min_curvature}, max {max_curvature}, c {c}")
-                c = c[np.newaxis].T
-                max_color = np.array(node.curvature_color)
-                min_color = 2*main_color - max_color
-                #print(f"C: min {min_color}, avg {main_color}, max {max_color}")
-                surface_colors = (1 - c)*min_color + c*max_color
+                if max_curvature > 0:
+                    positive = (curvature_values > 0)
+                    c = curvature_values[positive] / max_curvature
+                    c = c[np.newaxis].T
+                    surface_colors[positive] = (1 - c)*main_color + c*max_color
+                if min_curvature < 0:
+                    negative = (curvature_values < 0)
+                    c = (min_curvature - curvature_values[negative]) / min_curvature
+                    c = c[np.newaxis].T
+                    surface_colors[negative] = (1 - c)*min_color + c*main_color
         else:
             surface_colors = np.empty((resolution_u*resolution_v, 4))
             surface_colors[:] = main_color

utils/surface/data.py

@@ -134,9 +134,6 @@ def gauss(self):
         curvature = np.zeros_like(numerator)
         good = (denominator != 0)
         curvature[good] = numerator[good] / denominator[good]
-        print(f"G: num {numerator}")
-        print(f"G: den {denominator}")
-        print(f"G: c {curvature}")
         return curvature
 
     def curvature_along_direction(self, v1, v2):