Merge pull request #5162 from nortikin/snap_curves

"Snap curves" node

docs/nodes/curve/snap_curves.rst

@@ -0,0 +1,100 @@
+Snap Curves
+===========
+
+Functionality
+-------------
+
+This node takes two or more NURBS curve objects, and modifies them in such a
+way that they become connected: end point of first curve coincides with start
+point of the second curve, and so on. It is possible to define, which curve
+must become "main" , and which curve should be adjusted in order to match the
+"main" curve.
+
+Optionally, this node can also adjust directions of curves at their start and
+end points.
+
+For this node, direction and order of curves are important. If you have several
+curves with arbitrary directions, you may want to use "Sort Curves" node first,
+to ensure that the end of each curve is near the beginning of the next curve.
+
+This node can work with NURBS and NURBS-like curves only. It adjusts curves by
+moving their control points, while trying to move all points as less as
+possible. This means that curve structure is important for this node. For
+example,
+
+* If the curve has a lot of control points, the node will have to move only one
+  or two of it's control points near the end, so that most of the curve will be
+  left unchanged.
+* If the curve has only a few of control points, for example 3 or 4, then
+  movement of 1 or 2 control points can move almost whole curve.
+* For curves with higher degree, each control point controls wider span of the
+  curve. So when adjusting curves with higher degree, wider span of the curve
+  will be moved.
+
+Inputs
+------
+
+This node has the following inputs:
+
+* **Curve1**. First curve to process. This input is available and mandatory
+  only if **Input Mode** parameter is set to **Two Curves**.
+* **Curve2**. Second curve to process. This input is available and mandatory
+  only if **Input Mode** parameter is set to **Two Curves**.
+* **Curves**. List of curves to be processed. This input is available and mandatory
+  only if **Input Mode** parameter is set to **List of Curves**.
+
+Parameters
+----------
+
+This node has the following parameters:
+
+* **Input Mode**. The available options are **Two Curves** and **List of
+  Curves**. The default option is **Two Curves**.
+* **Bias**. This defines where two curves should meet. The available options are:
+
+  * **Middle**. The meeting point will be defined as middle between end of
+    first curve and start of second curve.
+  * **Curve 1**. First curve will be considered "main", so it's end point will
+    not be moved; start point of the second curve will be moved to end point of
+    the first curve.
+  * **Curve 2**. Second curve will be considered "main", so it's start point
+    will not be moved; end point fo the first curve will be moved to start
+    point of the second curve.
+
+  The default option is **Middle**.
+* **Tangents**. This defines whether the node should adjust directions of
+  curves at their ends, and how exactly. The available options are:
+
+  * **No matter**. The node will not bother about curve directions, and try to
+    move curve ends properly while moving control points as less as possible.
+  * **Preserve**. The node will try to preserve directions of the curves at their ends.
+  * **Medium**. The node will adjust the directions of curves at their ends in
+    such a way, that their tangent vectors will be equal to average between
+    tangent vector of the first curve at it's end and tangent vector of the
+    second curve at it's beginning.
+  * **Curve 1**. The node will preserve the direction of the first curve at
+    it's end, and adjust the direction of the second curve at it's beginning to
+    match the first curve.
+  * **Curve 2**. The node will preserve the direction of the second curve at
+    it's beginning, and adjust the direction of the first curve at it's end to
+    match the second curve.
+
+  The default option is **No matter**.
+
+* **Cyclic**. If checked, the node will also try to connect the end point of
+  last curve to the start point of the first curve, in order to create a closed
+  loop. Unchecked by default.
+
+Outputs
+-------
+
+This node has the following output:
+
+* **Curves**. The resulting curves.
+
+Example of Usage
+----------------
+
+.. image:: ../../../docs/assets/nodes/curve/snap_curves.gif
+   :target: ../../../docs/assets/nodes/curve/snap_curves.gif
+

index.yaml

@@ -96,6 +96,7 @@
         - SvNurbsCurveNodesNode
         - ---
         - SvNurbsCurveMovePointNode
+        - SvSnapCurvesNode
         - ---
         - SvCurveInsertKnotNode
         - SvCurveRemoveKnotNode

menus/full_by_data_type.yaml

@@ -291,6 +291,7 @@
         - SvProjectCurveSurfaceNode
         - ---
         - SvNurbsCurveMovePointNode
+        - SvSnapCurvesNode
         - ---
         - SvCurveInsertKnotNode
         - SvCurveRemoveKnotNode

menus/full_nortikin.yaml

@@ -182,6 +182,7 @@
         - icon_name: OUTLINER_OB_CURVE
         - extra_menu: AdvancedObjectsPartialMenu
         - SvNurbsCurveMovePointNode
+        - SvSnapCurvesNode
         - SvExApplyFieldToCurveNode
     - T SURFACES:
         - icon_name: SURFACE_DATA

nodes/curve/snap_curves.py

@@ -0,0 +1,139 @@
+# This file is part of project Sverchok. It's copyrighted by the contributors
+# recorded in the version control history of the file, available from
+# its original location https://github.com/nortikin/sverchok/commit/master
+#
+# SPDX-License-Identifier: GPL3
+# License-Filename: LICENSE
+
+import numpy as np
+
+import bpy
+from bpy.props import FloatProperty, EnumProperty, BoolProperty, IntProperty
+
+from sverchok.node_tree import SverchCustomTreeNode
+from sverchok.data_structure import updateNode, zip_long_repeat, ensure_nesting_level, get_data_nesting_level
+from sverchok.utils.curve import SvCurve
+from sverchok.utils.curve.nurbs import SvNurbsCurve
+from sverchok.utils.curve.nurbs_solver_applications import (
+        snap_curves,
+        BIAS_CURVE1, BIAS_CURVE2, BIAS_MID,
+        TANGENT_ANY, TANGENT_PRESERVE, TANGENT_MATCH,
+        TANGENT_CURVE1, TANGENT_CURVE2
+    )
+
+class SvSnapCurvesNode(SverchCustomTreeNode, bpy.types.Node):
+    """
+    Triggers: Snap Curves
+    Tooltip: Snap ends of curves to common point, optionally controlling curve tangents.
+    """
+    bl_idname = 'SvSnapCurvesNode'
+    bl_label = 'Snap NURBS Curves'
+    bl_icon = 'OUTLINER_OB_EMPTY'
+    sv_icon = 'SV_SNAP_CURVES'
+
+    bias_modes = [
+            (BIAS_MID, "Middle point", "Snap to middle point between end of first curve and start of second curve", 0),
+            (BIAS_CURVE1, "Curve 1", "Snap start of second curve to the end of the first curve", 1),
+            (BIAS_CURVE2, "Curve 2", "Snap end of first curve to the start of the second curve",
+             2)
+        ]
+
+    tangent_modes = [
+            (TANGENT_ANY, "No matter", "Tangents will probably change", 0),
+            (TANGENT_PRESERVE, "Preserve", "Preserve tangent vectors of all curves at both ends", 1),
+            (TANGENT_MATCH, "Medium", "Adjust tangent vectors of curves so that they will be average between end tangent of the first curve and start tangent of the second curve", 2),
+            (TANGENT_CURVE1, "Curve 1", "Preserve tangent vector of the first curve at it's end, and adjust the tangent vector of the second curve to match", 3),
+            (TANGENT_CURVE2, "Curve 2", "Preserve tangent vector of the second curve at it'send, and adjust the tangent vector of the first curve to match", 4)
+        ]
+
+    input_modes = [
+        ('TWO', "Two curves", "Process two curves", 0),
+        ('N', "List of curves", "Process several curves", 1)
+    ]
+
+    def update_sockets(self, context):
+        self.inputs['Curve1'].hide_safe = self.input_mode != 'TWO'
+        self.inputs['Curve2'].hide_safe = self.input_mode != 'TWO'
+        self.inputs['Curves'].hide_safe = self.input_mode != 'N'
+        updateNode(self, context)
+
+    input_mode : EnumProperty(
+        name = "Input mode",
+        items = input_modes,
+        default = 'TWO',
+        update = update_sockets)
+
+    bias : EnumProperty(
+            name = "Bias",
+            items = bias_modes,
+            update = updateNode)
+
+    tangent : EnumProperty(
+            name = "Tangents",
+            items = tangent_modes,
+            update = updateNode)
+
+    cyclic : BoolProperty(
+            name = "Cyclic",
+            default = False,
+            update = updateNode)
+
+    def sv_init(self, context):
+        self.inputs.new('SvCurveSocket', "Curves")
+        self.inputs.new('SvCurveSocket', "Curve1")
+        self.inputs.new('SvCurveSocket', "Curve2")
+        self.outputs.new('SvCurveSocket', "Curves")
+        self.update_sockets(context)
+
+    def draw_buttons(self, context, layout):
+        layout.prop(self, 'input_mode', text='')
+        layout.prop(self, 'bias')
+        layout.prop(self, 'tangent')
+        layout.prop(self, 'cyclic')
+
+    def get_inputs(self):
+        curves_s = []
+        if self.input_mode == 'TWO':
+            curve1_s = self.inputs['Curve1'].sv_get()
+            curve2_s = self.inputs['Curve2'].sv_get()
+            level1 = get_data_nesting_level(curve1_s, data_types=(SvCurve,))
+            level2 = get_data_nesting_level(curve2_s, data_types=(SvCurve,))
+            nested_input = level1 > 1 or level2 > 1
+            curve1_s = ensure_nesting_level(curve1_s, 2, data_types=(SvCurve,))
+            curve2_s = ensure_nesting_level(curve2_s, 2, data_types=(SvCurve,))
+            for inputs in zip_long_repeat(curve1_s, curve2_s):
+                curves_s.append( list( *zip_long_repeat(*inputs) ) )
+        else:
+            curves_s = self.inputs['Curves'].sv_get()
+            level = get_data_nesting_level(curves_s, data_types=(SvCurve,))
+            nested_input = level > 1
+            curves_s = ensure_nesting_level(curves_s, 2, data_types=(SvCurve,))
+        return nested_input, curves_s
+
+    def process(self):
+        if not any(socket.is_linked for socket in self.outputs):
+            return
+
+        curves_out = []
+        nested_input, curves_s = self.get_inputs()
+        for curves in curves_s:
+            curves = [SvNurbsCurve.to_nurbs(c) for c in curves]
+            if any(c is None for c in curves):
+                raise Exception("Some of curves are not NURBS!")
+            new_curves = snap_curves(curves,
+                                     bias = self.bias,
+                                     tangent = self.tangent,
+                                     cyclic = self.cyclic)
+            if nested_input:
+                curves_out.append(new_curves)
+            else:
+                curves_out.extend(new_curves)
+
+        self.outputs['Curves'].sv_set(curves_out)
+
+def register():
+    bpy.utils.register_class(SvSnapCurvesNode)
+
+def unregister():
+    bpy.utils.unregister_class(SvSnapCurvesNode)
+