feat: Implement weight cutout boundary smoothing for image depth cutout

- Added a new proposal for boundary smoothing in the weight cutout process, differentiating between Split edges and Outline smoothing requirements.
- Introduced a new capability `cutout-boundary-smoothing` to control smoothing strength and default values.
- Updated specifications to define the behavior of boundary-specific smoothing strength and default settings.
- Created tasks to verify the implementation of boundary behavior and asset updates.
- Developed comprehensive tests for depth symmetry and normal scaling to ensure expected behavior and performance.
- Introduced new attributes for normal mapping to facilitate persistent face attributes sharing between depth symmetry and image materials.
- Built a new node group for O Image Depth Symmetry, integrating the new smoothing capabilities and ensuring compatibility with existing workflows.

tools/nodes/groups/image_depth_cutout.py

@@ -1,7 +1,7 @@
 """Build O Image Depth Cutout."""
 import bpy
 from mathutils import Matrix
-from anyimage.operators.cutout_tool.shape import CUTOUT_Z_TO_X, NORMAL_SCALE_ATTRIBUTE_NAME
+from anyimage.operators.cutout_tool.shape import CUTOUT_Z_TO_X, NORMAL_REDUCTION_ATTRIBUTE_NAME
 from ..common.nodes import interface_socket, group_input, math_node, float_input, menu_switch, read_float_attribute, store_float_attribute, prepare_node_group, sample_field, evaluate_field
 from ..common.smoothing import expand_smooth
 from ..common.boundary_smoothing import smooth_cut_boundary
@@ -235,7 +235,7 @@ def build_shell_position(group, position, front, is_shell, fields):
     links.new(control.outputs["Thickness"], clamp.inputs["Value"])
     t = clamp.outputs[0]
     radius = _math(group, "MULTIPLY", _math(group, "SUBTRACT", front_z, fields["center"]), t)
-    rear = _math(group, "SUBTRACT", 1, read_float_attribute(group, "o_normal_scale"))
+    rear = read_float_attribute(group, NORMAL_REDUCTION_ATTRIBUTE_NAME)
     rear_radius = _math(group, "MULTIPLY", rear, _math(group, "ADD", radius, distance))
     direction = vector("SUBTRACT", fields["normal"], (0, 0, 1))
     rear_shift = vector("SCALE", direction, rear_radius)
@@ -277,7 +277,7 @@ def _build_depth_surface(group, geometry, controls):
     projection = project_depth_surface(
         group, geometry, camera, scale, controls.outputs["Reference Depth"], controls.outputs["Depth Scale"], split,
     )
-    projection = smooth_cut_boundary(group, projection)
+    projection = smooth_cut_boundary(group, projection, cut_vertex)
     # Clamped depth pixels can collapse adjacent outline samples after projection.
     edge = group.nodes.new("GeometryNodeInputMeshEdgeVertices")
     length = group.nodes.new("ShaderNodeVectorMath")
@@ -309,7 +309,7 @@ def _build_depth_surface(group, geometry, controls):
     front = build_front_fields(group, volume, normal, normal_weight)
     shell_fields = build_shell_fields(group, projection, volume, is_shell, normal_weight)
     shell = thicken_depth_surface(
-        group, projection, shell_fields["thickness"], back_mask=NORMAL_SCALE_ATTRIBUTE_NAME, weld_zero_thickness=True,
+        group, projection, shell_fields["thickness"], back_mask=NORMAL_REDUCTION_ATTRIBUTE_NAME, weld_zero_thickness=True,
     )
     fields = {
         name: sample_field(group, projection, value, data_type, index=shell["source_index"])
@@ -357,7 +357,7 @@ def build_image_depth_cutout_group():
     float_input(group, 'Reference Depth', 1.0, subtype='DISTANCE', parent=options)
     interface_socket(group, 'Depth Axis', 'INPUT', 'NodeSocketMenu', options).menu_expanded = True
     boundary_smooth = interface_socket(group, 'Boundary Smooth', 'INPUT', 'NodeSocketInt', options)
-    boundary_smooth.default_value, boundary_smooth.min_value, boundary_smooth.max_value = 0, 0, 16
+    boundary_smooth.default_value, boundary_smooth.min_value, boundary_smooth.max_value = 4, 0, 16
     boundary_smooth.description = 'Smooth geometry near the original outline and Depth Split edges. Zero disables boundary smoothing.'
     normal_smooth = interface_socket(group, 'Normal Smooth', 'INPUT', 'NodeSocketInt', options)
     normal_smooth.default_value, normal_smooth.min_value, normal_smooth.max_value = 64, 16, 512
@@ -372,7 +372,7 @@ def build_image_depth_cutout_group():
     area.inputs[1].default_value = 0.01
     group.links.new(base.outputs['Cleanup Threshold'], area.inputs[0])
     cleaned = _island_cleanup(group, base.outputs['Geometry'], area.outputs[0])
-    cleaned = store_float_attribute(group, cleaned, NORMAL_SCALE_ATTRIBUTE_NAME, 1.0, domain='FACE')
+    cleaned = store_float_attribute(group, cleaned, NORMAL_REDUCTION_ATTRIBUTE_NAME, 0.0, domain='FACE')
     controls = group_input(group.nodes, set())
     geometry = _build_depth_surface(group, cleaned, controls)
     geometry = expand_smooth(group, geometry, iterations_name='Smooth', weight_name='Smooth Weight')