From 655df71cd8a1f772a42b8033e4fc87e2ad6ac6a5 Mon Sep 17 00:00:00 2001
From: bklronin <therrmann23@gmail.com>
Date: Fri, 7 Aug 2026 15:44:53 +0200
Subject: [PATCH] - arc improvements, fillets, operations, bodys

---
 .idea/workspace.xml              |  99 +++++++------
 gui.ui                           |   7 +
 gui_ui.py                        |  70 ++++-----
 src/fluency/io/project_io.py     |   6 +
 src/fluency/models/data_model.py |  27 ++--
 src/fluency/ui/dialogs.py        | 240 +++++++++++++++++++++++++++++++
 src/fluency/ui/main_window.py    | 159 +++++++++++++++++++-
 src/fluency/ui/sketch_widget.py  | 137 +++++++++++++-----
 8 files changed, 619 insertions(+), 126 deletions(-)

diff --git a/.idea/workspace.xml b/.idea/workspace.xml
index c52df94..fd0e8d9 100644
--- a/.idea/workspace.xml
+++ b/.idea/workspace.xml
@@ -7,8 +7,11 @@
     <list default="true" id="8f0bafd6-58a0-4b20-aa2b-ddc3ba278873" name="Changes" comment="- arc improvements, fillets, operations, bodys">
       <change beforePath="$PROJECT_DIR$/.idea/workspace.xml" beforeDir="false" afterPath="$PROJECT_DIR$/.idea/workspace.xml" afterDir="false" />
       <change beforePath="$PROJECT_DIR$/gui.ui" beforeDir="false" afterPath="$PROJECT_DIR$/gui.ui" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/src/fluency/geometry_occ/sketch.py" beforeDir="false" afterPath="$PROJECT_DIR$/src/fluency/geometry_occ/sketch.py" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/src/fluency/sketch_solver.py" beforeDir="false" afterPath="$PROJECT_DIR$/src/fluency/sketch_solver.py" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/gui_ui.py" beforeDir="false" afterPath="$PROJECT_DIR$/gui_ui.py" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/src/fluency/io/project_io.py" beforeDir="false" afterPath="$PROJECT_DIR$/src/fluency/io/project_io.py" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/src/fluency/models/data_model.py" beforeDir="false" afterPath="$PROJECT_DIR$/src/fluency/models/data_model.py" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/src/fluency/ui/dialogs.py" beforeDir="false" afterPath="$PROJECT_DIR$/src/fluency/ui/dialogs.py" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/src/fluency/ui/main_window.py" beforeDir="false" afterPath="$PROJECT_DIR$/src/fluency/ui/main_window.py" afterDir="false" />
       <change beforePath="$PROJECT_DIR$/src/fluency/ui/sketch_widget.py" beforeDir="false" afterPath="$PROJECT_DIR$/src/fluency/ui/sketch_widget.py" afterDir="false" />
     </list>
     <option name="SHOW_DIALOG" value="false" />
@@ -46,47 +49,47 @@
     <option name="hideEmptyMiddlePackages" value="true" />
     <option name="showLibraryContents" value="true" />
   </component>
-  <component name="PropertiesComponent">{
-  &quot;keyToString&quot;: {
-    &quot;Python.2dtest.executor&quot;: &quot;Run&quot;,
-    &quot;Python.3d_windows.executor&quot;: &quot;Run&quot;,
-    &quot;Python.Unnamed.executor&quot;: &quot;Run&quot;,
-    &quot;Python.base.executor&quot;: &quot;Run&quot;,
-    &quot;Python.data_model.executor&quot;: &quot;Run&quot;,
-    &quot;Python.debug_dragging.executor&quot;: &quot;Run&quot;,
-    &quot;Python.draw_widget2d.executor&quot;: &quot;Run&quot;,
-    &quot;Python.draw_widget_solve.executor&quot;: &quot;Run&quot;,
-    &quot;Python.fluency.executor&quot;: &quot;Run&quot;,
-    &quot;Python.fluencyb.executor&quot;: &quot;Run&quot;,
-    &quot;Python.gl_widget.executor&quot;: &quot;Run&quot;,
-    &quot;Python.gui_ui.executor&quot;: &quot;Run&quot;,
-    &quot;Python.kernel.executor&quot;: &quot;Run&quot;,
-    &quot;Python.main.executor&quot;: &quot;Run&quot;,
-    &quot;Python.main_window.executor&quot;: &quot;Run&quot;,
-    &quot;Python.meshtest.executor&quot;: &quot;Run&quot;,
-    &quot;Python.occ_renderer.executor&quot;: &quot;Run&quot;,
-    &quot;Python.occ_to_mesh.executor&quot;: &quot;Run&quot;,
-    &quot;Python.render_backend.executor&quot;: &quot;Run&quot;,
-    &quot;Python.side_fluency.executor&quot;: &quot;Run&quot;,
-    &quot;Python.simple_mesh.executor&quot;: &quot;Run&quot;,
-    &quot;Python.sketch.executor&quot;: &quot;Run&quot;,
-    &quot;Python.vtk_widget.executor&quot;: &quot;Run&quot;,
-    &quot;Python.vulkan.executor&quot;: &quot;Run&quot;,
-    &quot;RunOnceActivity.OpenProjectViewOnStart&quot;: &quot;true&quot;,
-    &quot;RunOnceActivity.ShowReadmeOnStart&quot;: &quot;true&quot;,
-    &quot;RunOnceActivity.TerminalTabsStorage.copyFrom.TerminalArrangementManager.252&quot;: &quot;true&quot;,
-    &quot;RunOnceActivity.git.unshallow&quot;: &quot;true&quot;,
-    &quot;RunOnceActivity.typescript.service.memoryLimit.init&quot;: &quot;true&quot;,
-    &quot;codeWithMe.voiceChat.enabledByDefault&quot;: &quot;false&quot;,
-    &quot;git-widget-placeholder&quot;: &quot;feature/occ-migration&quot;,
-    &quot;last_opened_file_path&quot;: &quot;/Volumes/Data_drive/Programming/fluency&quot;,
-    &quot;node.js.detected.package.eslint&quot;: &quot;true&quot;,
-    &quot;node.js.selected.package.eslint&quot;: &quot;(autodetect)&quot;,
-    &quot;node.js.selected.package.tslint&quot;: &quot;(autodetect)&quot;,
-    &quot;nodejs_package_manager_path&quot;: &quot;npm&quot;,
-    &quot;settings.editor.selected.configurable&quot;: &quot;project.propVCSSupport.DirectoryMappings&quot;
+  <component name="PropertiesComponent"><![CDATA[{
+  "keyToString": {
+    "Python.2dtest.executor": "Run",
+    "Python.3d_windows.executor": "Run",
+    "Python.Unnamed.executor": "Run",
+    "Python.base.executor": "Run",
+    "Python.data_model.executor": "Run",
+    "Python.debug_dragging.executor": "Run",
+    "Python.draw_widget2d.executor": "Run",
+    "Python.draw_widget_solve.executor": "Run",
+    "Python.fluency.executor": "Run",
+    "Python.fluencyb.executor": "Run",
+    "Python.gl_widget.executor": "Run",
+    "Python.gui_ui.executor": "Run",
+    "Python.kernel.executor": "Run",
+    "Python.main.executor": "Run",
+    "Python.main_window.executor": "Run",
+    "Python.meshtest.executor": "Run",
+    "Python.occ_renderer.executor": "Run",
+    "Python.occ_to_mesh.executor": "Run",
+    "Python.render_backend.executor": "Run",
+    "Python.side_fluency.executor": "Run",
+    "Python.simple_mesh.executor": "Run",
+    "Python.sketch.executor": "Run",
+    "Python.vtk_widget.executor": "Run",
+    "Python.vulkan.executor": "Run",
+    "RunOnceActivity.OpenProjectViewOnStart": "true",
+    "RunOnceActivity.ShowReadmeOnStart": "true",
+    "RunOnceActivity.TerminalTabsStorage.copyFrom.TerminalArrangementManager.252": "true",
+    "RunOnceActivity.git.unshallow": "true",
+    "RunOnceActivity.typescript.service.memoryLimit.init": "true",
+    "codeWithMe.voiceChat.enabledByDefault": "false",
+    "git-widget-placeholder": "feature/occ-migration",
+    "last_opened_file_path": "/Volumes/Data_drive/Programming/fluency/src/fluency/Tesfiles",
+    "node.js.detected.package.eslint": "true",
+    "node.js.selected.package.eslint": "(autodetect)",
+    "node.js.selected.package.tslint": "(autodetect)",
+    "nodejs_package_manager_path": "npm",
+    "settings.editor.selected.configurable": "project.propVCSSupport.DirectoryMappings"
   }
-}</component>
+}]]></component>
   <component name="QodanaReportsService">
     <option name="descriptions">
       <ReportDescription localRun="true" path="/private/var/folders/kg/zm48w_r96yb68mlbzvb9gtq40000gn/T/qodana_output/qodana.sarif.json" reportGuid="5f5b823c-c594-48c5-ae1f-062e30303918" reportId="fluency/qodana/2024-02-04" />
@@ -94,11 +97,11 @@
   </component>
   <component name="RecentsManager">
     <key name="CopyFile.RECENT_KEYS">
+      <recent name="$PROJECT_DIR$/src/fluency/Tesfiles" />
       <recent name="$PROJECT_DIR$" />
       <recent name="$PROJECT_DIR$/src/fluency" />
       <recent name="$PROJECT_DIR$/src/fluency/rendering" />
       <recent name="$PROJECT_DIR$/drawing_modules" />
-      <recent name="$PROJECT_DIR$/modules" />
     </key>
     <key name="MoveFile.RECENT_KEYS">
       <recent name="$PROJECT_DIR$" />
@@ -480,7 +483,15 @@
       <option name="project" value="LOCAL" />
       <updated>1785941246695</updated>
     </task>
-    <option name="localTasksCounter" value="46" />
+    <task id="LOCAL-00046" summary="- arc improvements, fillets, operations, bodys">
+      <option name="closed" value="true" />
+      <created>1785948828454</created>
+      <option name="number" value="00046" />
+      <option name="presentableId" value="LOCAL-00046" />
+      <option name="project" value="LOCAL" />
+      <updated>1785948828454</updated>
+    </task>
+    <option name="localTasksCounter" value="47" />
     <servers />
   </component>
   <component name="TypeScriptGeneratedFilesManager">
diff --git a/gui.ui b/gui.ui
index 227fb96..75f91ac 100644
--- a/gui.ui
+++ b/gui.ui
@@ -1233,6 +1233,13 @@
          </property>
         </widget>
        </item>
+       <item row="6" column="1">
+        <widget class="QPushButton" name="pb_mirror_op">
+         <property name="text">
+          <string>Mirror</string>
+         </property>
+        </widget>
+       </item>
       </layout>
      </widget>
     </item>
diff --git a/gui_ui.py b/gui_ui.py
index 68af409..4dd1b2e 100644
--- a/gui_ui.py
+++ b/gui_ui.py
@@ -628,50 +628,55 @@ class Ui_fluencyCAD(object):
         self.groupBox.setMaximumSize(QSize(200, 16777215))
         self.gridLayout_3 = QGridLayout(self.groupBox)
         self.gridLayout_3.setObjectName(u"gridLayout_3")
-        self.pb_combop = QPushButton(self.groupBox)
-        self.pb_combop.setObjectName(u"pb_combop")
+        self.pb_chamfer_op = QPushButton(self.groupBox)
+        self.pb_chamfer_op.setObjectName(u"pb_chamfer_op")
 
-        self.gridLayout_3.addWidget(self.pb_combop, 1, 0, 1, 1)
-
-        self.pb_arrayop = QPushButton(self.groupBox)
-        self.pb_arrayop.setObjectName(u"pb_arrayop")
-
-        self.gridLayout_3.addWidget(self.pb_arrayop, 2, 0, 1, 1)
-
-        self.pb_moveop = QPushButton(self.groupBox)
-        self.pb_moveop.setObjectName(u"pb_moveop")
-
-        self.gridLayout_3.addWidget(self.pb_moveop, 1, 1, 1, 1)
-
-        self.pb_revop = QPushButton(self.groupBox)
-        self.pb_revop.setObjectName(u"pb_revop")
-
-        self.gridLayout_3.addWidget(self.pb_revop, 2, 1, 1, 1)
+        self.gridLayout_3.addWidget(self.pb_chamfer_op, 2, 1, 1, 1)
 
         self.pb_fillet_op = QPushButton(self.groupBox)
         self.pb_fillet_op.setObjectName(u"pb_fillet_op")
 
-        self.gridLayout_3.addWidget(self.pb_fillet_op, 3, 0, 1, 1)
+        self.gridLayout_3.addWidget(self.pb_fillet_op, 2, 0, 1, 1)
+
+        self.pb_thread = QPushButton(self.groupBox)
+        self.pb_thread.setObjectName(u"pb_thread")
+
+        self.gridLayout_3.addWidget(self.pb_thread, 6, 0, 1, 1)
 
         self.pb_extrdop = QPushButton(self.groupBox)
         self.pb_extrdop.setObjectName(u"pb_extrdop")
 
         self.gridLayout_3.addWidget(self.pb_extrdop, 0, 0, 1, 1)
 
+        self.pb_revop = QPushButton(self.groupBox)
+        self.pb_revop.setObjectName(u"pb_revop")
+
+        self.gridLayout_3.addWidget(self.pb_revop, 4, 1, 1, 1)
+
         self.pb_cutop = QPushButton(self.groupBox)
         self.pb_cutop.setObjectName(u"pb_cutop")
 
         self.gridLayout_3.addWidget(self.pb_cutop, 0, 1, 1, 1)
 
-        self.pb_chamfer = QPushButton(self.groupBox)
-        self.pb_chamfer.setObjectName(u"pb_chamfer")
+        self.pb_arrayop = QPushButton(self.groupBox)
+        self.pb_arrayop.setObjectName(u"pb_arrayop")
 
-        self.gridLayout_3.addWidget(self.pb_chamfer, 3, 1, 1, 1)
+        self.gridLayout_3.addWidget(self.pb_arrayop, 4, 0, 1, 1)
 
-        self.pb_thread = QPushButton(self.groupBox)
-        self.pb_thread.setObjectName(u"pb_thread")
+        self.pb_combop = QPushButton(self.groupBox)
+        self.pb_combop.setObjectName(u"pb_combop")
 
-        self.gridLayout_3.addWidget(self.pb_thread, 4, 0, 1, 1)
+        self.gridLayout_3.addWidget(self.pb_combop, 1, 0, 1, 1)
+
+        self.pb_moveop = QPushButton(self.groupBox)
+        self.pb_moveop.setObjectName(u"pb_moveop")
+
+        self.gridLayout_3.addWidget(self.pb_moveop, 1, 1, 1, 1)
+
+        self.pb_mirror_op = QPushButton(self.groupBox)
+        self.pb_mirror_op.setObjectName(u"pb_mirror_op")
+
+        self.gridLayout_3.addWidget(self.pb_mirror_op, 6, 1, 1, 1)
 
 
         self.gridLayout.addWidget(self.groupBox, 0, 3, 1, 1)
@@ -922,15 +927,16 @@ class Ui_fluencyCAD(object):
         self.pb_offset_tool.setText(QCoreApplication.translate("fluencyCAD", u"Offst", None))
         self.assembly_box.setTitle(QCoreApplication.translate("fluencyCAD", u"Assembly", None))
         self.groupBox.setTitle(QCoreApplication.translate("fluencyCAD", u"Modify", None))
-        self.pb_combop.setText(QCoreApplication.translate("fluencyCAD", u"Comb", None))
-        self.pb_arrayop.setText(QCoreApplication.translate("fluencyCAD", u"Array", None))
-        self.pb_moveop.setText(QCoreApplication.translate("fluencyCAD", u"Mve", None))
-        self.pb_revop.setText(QCoreApplication.translate("fluencyCAD", u"Rev", None))
+        self.pb_chamfer_op.setText(QCoreApplication.translate("fluencyCAD", u"Chamfer", None))
         self.pb_fillet_op.setText(QCoreApplication.translate("fluencyCAD", u"Fillet", None))
-        self.pb_extrdop.setText(QCoreApplication.translate("fluencyCAD", u"Extrd", None))
-        self.pb_cutop.setText(QCoreApplication.translate("fluencyCAD", u"Cut", None))
-        self.pb_chamfer.setText(QCoreApplication.translate("fluencyCAD", u"Chamfer", None))
         self.pb_thread.setText(QCoreApplication.translate("fluencyCAD", u"Thread", None))
+        self.pb_extrdop.setText(QCoreApplication.translate("fluencyCAD", u"Extrd", None))
+        self.pb_revop.setText(QCoreApplication.translate("fluencyCAD", u"Rev", None))
+        self.pb_cutop.setText(QCoreApplication.translate("fluencyCAD", u"Cut", None))
+        self.pb_arrayop.setText(QCoreApplication.translate("fluencyCAD", u"Arry", None))
+        self.pb_combop.setText(QCoreApplication.translate("fluencyCAD", u"Comb", None))
+        self.pb_moveop.setText(QCoreApplication.translate("fluencyCAD", u"Mve", None))
+        self.pb_mirror_op.setText(QCoreApplication.translate("fluencyCAD", u"Mirror", None))
         self.groupBox_10.setTitle(QCoreApplication.translate("fluencyCAD", u"Bodys / Operations", None))
         self.groupBox_8.setTitle(QCoreApplication.translate("fluencyCAD", u"Tools", None))
         self.pb_body_hide.setText(QCoreApplication.translate("fluencyCAD", u"Hide", None))
diff --git a/src/fluency/io/project_io.py b/src/fluency/io/project_io.py
index 9357b6f..9d1f864 100644
--- a/src/fluency/io/project_io.py
+++ b/src/fluency/io/project_io.py
@@ -230,6 +230,9 @@ def _feature_to_dict(feat: Feature) -> Dict[str, Any]:
         "count": feat.count,
         "spacing": feat.spacing,
         "direction": [float(v) for v in (feat.direction or (1, 0, 0))],
+        "mirror_plane_origin": [float(v) for v in (feat.mirror_plane_origin or (0.0, 0.0, 0.0))],
+        "mirror_plane_normal": [float(v) for v in (feat.mirror_plane_normal or (1, 0, 0))],
+        "keep_original": bool(feat.keep_original),
     }
 
 
@@ -257,6 +260,9 @@ def _feature_from_dict(data: Dict[str, Any], sketches: Dict[str, Sketch]) -> Fea
         count=int(data.get("count") or 2),
         spacing=_to_float(data.get("spacing"), 10.0),
         direction=tuple(float(v) for v in (data.get("direction") or (1, 0, 0))),
+        mirror_plane_origin=tuple(float(v) for v in (data.get("mirror_plane_origin") or (0.0, 0.0, 0.0))),
+        mirror_plane_normal=tuple(float(v) for v in (data.get("mirror_plane_normal") or (1, 0, 0))),
+        keep_original=bool(data.get("keep_original", True)),
     )
     sid = data.get("sketch_id")
     if sid and sid in sketches:
diff --git a/src/fluency/models/data_model.py b/src/fluency/models/data_model.py
index 0d23f45..924f743 100644
--- a/src/fluency/models/data_model.py
+++ b/src/fluency/models/data_model.py
@@ -229,17 +229,21 @@ class Feature:
       - "chamfer": bevel a set of edges of the running geometry
                   (same fields as "fillet"; ``radius`` holds the
                   chamfer size)
+      - "mirror": mirror the running solid across a plane defined by
+                  ``mirror_plane_origin`` and ``mirror_plane_normal``.
+                  When ``keep_original`` is True (the default), the
+                  original solid is boolean-union'd with its mirror
       - "array" / "pattern": repeat the running solid in a linear or
-                  circular array.  ``pattern_type`` is "linear" or
-                  "circular"; ``count`` is the total number of items
-                  (original + copies).  Linear uses ``direction``
-                  (unit vector) and ``spacing`` (mm between adjacent
-                  items); circular reuses ``axis`` + ``origin`` for the
-                  rotation axis and ``angle`` for the total angular
-                  span in degrees (copies evenly distributed).
+                 circular array.  ``pattern_type`` is "linear" or
+                 "circular"; ``count`` is the total number of items
+                 (original + copies).  Linear uses ``direction``
+                 (unit vector) and ``spacing`` (mm between adjacent
+                 items); circular reuses ``axis`` + ``origin`` for the
+                 rotation axis and ``angle`` for the total angular
+                 span in degrees (copies evenly distributed).
       - "base":   frozen geometry snapshot (``geometry`` field) — used
-                  to migrate legacy bodies whose original base feature
-                  is unknown.  Never the result of a user operation.
+                 to migrate legacy bodies whose original base feature
+                 is unknown.  Never the result of a user operation.
     """
 
     id: str = field(default_factory=lambda: str(uuid.uuid4()))
@@ -281,6 +285,11 @@ class Feature:
     spacing: float = 10.0
     direction: Tuple[float, float, float] = (1.0, 0.0, 0.0)
 
+    # "mirror" feature only: mirror plane definition.
+    mirror_plane_origin: Tuple[float, float, float] = (0.0, 0.0, 0.0)
+    mirror_plane_normal: Tuple[float, float, float] = (1.0, 0.0, 0.0)
+    keep_original: bool = True
+
     created_at: datetime = field(default_factory=datetime.now)
 
 
diff --git a/src/fluency/ui/dialogs.py b/src/fluency/ui/dialogs.py
index 44f4c7d..9690abb 100644
--- a/src/fluency/ui/dialogs.py
+++ b/src/fluency/ui/dialogs.py
@@ -641,6 +641,246 @@ class ArrayDialog(QDialog):
         }
 
 
+class MirrorDialog(QDialog):
+    """Dialog for the mirror tool: plane selection with live preview.
+
+    Mirrors the selected body across a plane.  The user can pick a
+    plane from:
+
+      - A list of existing workplanes (combo box, passed by the caller)
+      - Six axis-aligned presets (XY, XZ, YZ and their negatives)
+      - Custom origin + normal enterable through spinboxes
+
+    ``keep_original`` (checked by default) boolean-unions the original
+    solid with its mirror image so you get a symmetric part from half
+    the modeling work.
+
+    A live-preview callback (``set_preview_callback``) fires on every
+    change so the host can show the mirrored shape in the 3D view
+    before committing.
+
+    ``get_values()`` returns a dict:
+    ``{"mirror_plane_origin", "mirror_plane_normal", "keep_original"}``.
+    """
+
+    def __init__(
+        self,
+        parent: Optional[QWidget] = None,
+        workplanes: Optional[list] = None,
+    ):
+        super().__init__(parent)
+        self.setWindowTitle("Mirror Options")
+        self.setMinimumWidth(400)
+
+        self._preview_callback: Optional[Callable[[Any], None]] = None
+        self._workplanes: list = workplanes if workplanes is not None else []
+
+        # Preset plane definitions: (label, normal, origin)
+        self._presets: list = [
+            ("XY (Top)", (0, 0, 1), (0, 0, 0)),
+            ("XZ (Front)", (0, 1, 0), (0, 0, 0)),
+            ("YZ (Right)", (1, 0, 0), (0, 0, 0)),
+            ("-XY (Bottom)", (0, 0, -1), (0, 0, 0)),
+            ("-XZ (Back)", (0, -1, 0), (0, 0, 0)),
+            ("-YZ (Left)", (-1, 0, 0), (0, 0, 0)),
+        ]
+
+        layout = QVBoxLayout(self)
+
+        # ── Plane source ──
+        src_layout = QHBoxLayout()
+        src_layout.addWidget(QLabel("Mirror plane:"))
+        self._wp_combo = QComboBox()
+        if self._workplanes:
+            for name, _origin, _normal in self._workplanes:
+                self._wp_combo.addItem(name)
+        else:
+            self._wp_combo.addItem("(no workplanes)")
+            self._wp_combo.setEnabled(False)
+        self._wp_combo.setToolTip("Pick an existing workplane as the mirror plane.")
+        src_layout.addWidget(self._wp_combo, 1)
+        layout.addLayout(src_layout)
+
+        # ── Preset radio buttons ──
+        preset_label = QLabel("Preset planes:")
+        layout.addWidget(preset_label)
+
+        self._preset_group = QButtonGroup(self)
+        preset_grid = QGridLayout()
+        for idx, (label, normal, origin) in enumerate(self._presets):
+            btn = QRadioButton(label)
+            btn.setChecked(idx == 0)  # XY default
+            self._preset_group.addButton(btn, idx)
+            preset_grid.addWidget(btn, idx // 2, idx % 2)
+        layout.addLayout(preset_grid)
+
+        # ── Custom origin ──
+        line1 = QFrame()
+        line1.setFrameShape(QFrame.Shape.HLine)
+        line1.setFrameShadow(QFrame.Shadow.Sunken)
+        layout.addWidget(line1)
+
+        origin_label = QLabel("Plane origin (mm):")
+        layout.addWidget(origin_label)
+        origin_row = QHBoxLayout()
+        origin_row.addWidget(QLabel("X:"))
+        self._origin_x = QDoubleSpinBox()
+        self._origin_x.setRange(-100000.0, 100000.0)
+        self._origin_x.setDecimals(2)
+        self._origin_x.setValue(0.0)
+        origin_row.addWidget(self._origin_x)
+        origin_row.addWidget(QLabel("Y:"))
+        self._origin_y = QDoubleSpinBox()
+        self._origin_y.setRange(-100000.0, 100000.0)
+        self._origin_y.setDecimals(2)
+        self._origin_y.setValue(0.0)
+        origin_row.addWidget(self._origin_y)
+        origin_row.addWidget(QLabel("Z:"))
+        self._origin_z = QDoubleSpinBox()
+        self._origin_z.setRange(-100000.0, 100000.0)
+        self._origin_z.setDecimals(2)
+        self._origin_z.setValue(0.0)
+        origin_row.addWidget(self._origin_z)
+        layout.addLayout(origin_row)
+
+        # ── Custom normal ──
+        normal_label = QLabel("Plane normal:")
+        layout.addWidget(normal_label)
+        normal_row = QHBoxLayout()
+        normal_row.addWidget(QLabel("X:"))
+        self._normal_x = QDoubleSpinBox()
+        self._normal_x.setRange(-1.0, 1.0)
+        self._normal_x.setSingleStep(1.0)
+        self._normal_x.setDecimals(0)
+        self._normal_x.setValue(0.0)
+        normal_row.addWidget(self._normal_x)
+        normal_row.addWidget(QLabel("Y:"))
+        self._normal_y = QDoubleSpinBox()
+        self._normal_y.setRange(-1.0, 1.0)
+        self._normal_y.setSingleStep(1.0)
+        self._normal_y.setDecimals(0)
+        self._normal_y.setValue(0.0)
+        normal_row.addWidget(self._normal_y)
+        normal_row.addWidget(QLabel("Z:"))
+        self._normal_z = QDoubleSpinBox()
+        self._normal_z.setRange(-1.0, 1.0)
+        self._normal_z.setSingleStep(1.0)
+        self._normal_z.setDecimals(0)
+        self._normal_z.setValue(1.0)
+        normal_row.addWidget(self._normal_z)
+        layout.addLayout(normal_row)
+
+        # ── Keep original ──
+        self._keep_original_cb = QCheckBox("Keep original")
+        self._keep_original_cb.setChecked(True)
+        self._keep_original_cb.setToolTip(
+            "When checked, the original solid is kept and union'd with its mirror image."
+        )
+        layout.addWidget(self._keep_original_cb)
+
+        # ── Buttons ──
+        line2 = QFrame()
+        line2.setFrameShape(QFrame.Shape.HLine)
+        line2.setFrameShadow(QFrame.Shadow.Sunken)
+        layout.addWidget(line2)
+
+        btn_layout = QHBoxLayout()
+        ok_btn = QPushButton("Mirror")
+        ok_btn.clicked.connect(self.accept)
+        cancel_btn = QPushButton("Cancel")
+        cancel_btn.clicked.connect(self.reject)
+        btn_layout.addWidget(ok_btn)
+        btn_layout.addWidget(cancel_btn)
+        layout.addLayout(btn_layout)
+
+        # ── Wire signals ──
+        self._wp_combo.currentIndexChanged.connect(self._on_workplane_selected)
+        self._preset_group.buttonClicked.connect(self._on_preset_changed)
+        for w in (self._origin_x, self._origin_y, self._origin_z,
+                  self._normal_x, self._normal_y, self._normal_z):
+            w.valueChanged.connect(self._emit_preview)
+        self._keep_original_cb.toggled.connect(self._emit_preview)
+
+        # Set initial values from the first preset (XY)
+        self._on_preset_changed(self._preset_group.button(0))
+
+    # ── Helpers ─────────────────────────────────────────────────────
+
+    def _on_workplane_selected(self, index: int) -> None:
+        """Fill origin / normal from the selected workplane."""
+        if index < 0 or index >= len(self._workplanes):
+            return
+        _name, origin, normal = self._workplanes[index]
+        self._origin_x.setValue(float(origin[0]))
+        self._origin_y.setValue(float(origin[1]))
+        self._origin_z.setValue(float(origin[2]))
+        self._normal_x.setValue(float(normal[0]))
+        self._normal_y.setValue(float(normal[1]))
+        self._normal_z.setValue(float(normal[2]))
+        self._emit_preview()
+
+    def _on_preset_changed(self, btn: QRadioButton) -> None:
+        """Fill origin / normal from the selected preset."""
+        idx = self._preset_group.id(btn)
+        if idx < 0 or idx >= len(self._presets):
+            return
+        _label, normal, origin = self._presets[idx]
+        self._origin_x.setValue(float(origin[0]))
+        self._origin_y.setValue(float(origin[1]))
+        self._origin_z.setValue(float(origin[2]))
+        self._normal_x.setValue(float(normal[0]))
+        self._normal_y.setValue(float(normal[1]))
+        self._normal_z.setValue(float(normal[2]))
+        self._emit_preview()
+
+    def _emit_preview(self) -> None:
+        """Fire the preview callback (if installed) with current values."""
+        if self._preview_callback is None:
+            return
+        values = self.get_values()
+        self._preview_callback(values)
+
+    def set_preview_callback(self, callback: Optional[Callable[[Any], None]]) -> None:
+        """Install a callback for live 3D preview of the mirrored shape.
+
+        The callback receives a ``dict`` with keys
+        ``mirror_plane_origin``, ``mirror_plane_normal``, and
+        ``keep_original``, or *None* to clear the preview.
+        """
+        self._preview_callback = callback
+        if callback is not None:
+            self._emit_preview()
+
+    def get_values(self) -> Dict[str, Any]:
+        """Return the current mirror parameters as a dict.
+
+        Keys: ``mirror_plane_origin`` (3-tuple), ``mirror_plane_normal``
+        (3-tuple, auto-normalized), ``keep_original`` (bool).
+        """
+        normal = (
+            self._normal_x.value(),
+            self._normal_y.value(),
+            self._normal_z.value(),
+        )
+        # Auto-normalize the normal vector (zero-vector → +Z).
+        import math as _math
+        nx, ny, nz = normal
+        norm = _math.sqrt(nx * nx + ny * ny + nz * nz)
+        if norm < 1e-12:
+            normal = (0.0, 0.0, 1.0)
+        else:
+            normal = (nx / norm, ny / norm, nz / norm)
+        return {
+            "mirror_plane_origin": (
+                self._origin_x.value(),
+                self._origin_y.value(),
+                self._origin_z.value(),
+            ),
+            "mirror_plane_normal": normal,
+            "keep_original": self._keep_original_cb.isChecked(),
+        }
+
+
 class WorkplaneOrientationDialog(QDialog):
     """Modal dialog to choose the orientation of a new workplane.
 
diff --git a/src/fluency/ui/main_window.py b/src/fluency/ui/main_window.py
index 2960572..61402a4 100644
--- a/src/fluency/ui/main_window.py
+++ b/src/fluency/ui/main_window.py
@@ -52,6 +52,7 @@ from fluency.ui.dialogs import (
     ExtrudeDialog,
     FilletDialog,
     OffsetDialog,
+    MirrorDialog,
     RevolveDialog,
     ThreadDialog,
     WorkplaneOrientationDialog,
@@ -1106,6 +1107,24 @@ def _replay_body_features(
                 return None
             continue
 
+        if feat.operation == "mirror":
+            # Mirror needs no sketch — it reflects the running solid.
+            if geom is None:
+                logger.warning(f"Body '{body.name}': mirror feature has no base, replay aborted")
+                return None
+            normal = feat.mirror_plane_normal if feat.mirror_plane_normal is not None else (1, 0, 0)
+            origin = feat.mirror_plane_origin if feat.mirror_plane_origin is not None else (0.0, 0.0, 0.0)
+            mirrored = kernel.mirror(geom, normal, origin)
+            if mirrored is None:
+                return None
+            if feat.keep_original:
+                geom = kernel.boolean_union(geom, mirrored)
+            else:
+                geom = mirrored
+            if geom is None:
+                return None
+            continue
+
         sketch = feat.sketch
         if sketch is None or sketch.occ_sketch is None:
             logger.warning(
@@ -1736,10 +1755,11 @@ class MainWindow(QMainWindow):
         self._btn_array = ui.pb_arrayop
         self._btn_fillet = ui.pb_fillet_op
         self._btn_fillet.setCheckable(True)
-        self._btn_chamfer = ui.pb_chamfer
+        self._btn_chamfer = ui.pb_chamfer_op
         self._btn_chamfer.setCheckable(True)
         self._btn_thread = ui.pb_thread
         self._btn_thread.setCheckable(True)
+        self._btn_mirror = ui.pb_mirror_op
         # ── Export ──
         self._btn_export_stl = ui.pushButton_2
         self._btn_export_step = ui.pb_export_step
@@ -1930,6 +1950,7 @@ class MainWindow(QMainWindow):
 
         # Generic buttons
         self._btn_move.clicked.connect(self._translate_body)
+        self._btn_mirror.clicked.connect(self._mirror_body)
         self._btn_array.clicked.connect(self._pattern_array)
         self._btn_offset.clicked.connect(self._offset_sketch)
         # Per-body hide/show toggle: the user clicks pb_body_hide next
@@ -2285,6 +2306,9 @@ class MainWindow(QMainWindow):
                 next((i for i, v in enumerate(direction) if v), -1), "?"
             )
             return f"{index + 1}. Linear pattern {count}× ({spacing:g} mm along {axis_name})"
+        if op == "mirror":
+            keep = " (keep original)" if feat.keep_original else ""
+            return f"{index + 1}. Mirror{keep}"
         if op == "base":
             return f"{index + 1}. Base (baked geometry)"
         return f"{index + 1}. {op.title()}"
@@ -4425,6 +4449,137 @@ class MainWindow(QMainWindow):
         self.statusBar().showMessage(f"{kind} array applied — {count} item(s)", 5000)
         logger.info(f"Applied {kind.lower()} array ({count} items) to '{body.name}'")
 
+    # ─── Mirror body ───────────────────────────────────────────────────────
+
+    def _mirror_body(self) -> None:
+        """Mirror the selected body across a plane (workplane or preset).
+
+        Opens the MirrorDialog asking for the mirror plane; on OK the body's
+        geometry is replaced by the mirrored copy (optionally union'd with
+        the original, so you get a symmetric part from half the work).  A
+        ``mirror`` feature is appended to the feature history so Update Body
+        and save/load replay it parametrically.
+        """
+        body = self._selected_body
+        if body is None or body.geometry is None:
+            QMessageBox.warning(
+                self,
+                "No Body",
+                "Select a body first — mirror reflects the selected body.",
+            )
+            return
+
+        # Gather workplane data for the dialog: list of (name, origin, normal).
+        wp_list: list = []
+        if self._current_component is not None:
+            wp_list = [
+                (wp.name, wp.origin, wp.normal)
+                for wp in self._current_component.workplanes.values()
+            ]
+
+        dialog = MirrorDialog(self, workplanes=wp_list)
+
+        def _preview(values: Any) -> None:
+            if values is None:
+                self._viewer_3d.clear_preview()
+                return
+            try:
+                normal = values["mirror_plane_normal"]
+                origin = values["mirror_plane_origin"]
+                keep = values["keep_original"]
+                mirrored = self._kernel.mirror(body.geometry, normal, origin)
+                if mirrored is None:
+                    self._viewer_3d.clear_preview()
+                    return
+                if keep:
+                    result = self._kernel.boolean_union(body.geometry, mirrored)
+                else:
+                    result = mirrored
+                if result is not None:
+                    shape = self._kernel._get_shape(result)
+                    self._viewer_3d.show_preview(shape)
+                else:
+                    self._viewer_3d.clear_preview()
+            except Exception:
+                logger.debug("mirror preview failed", exc_info=True)
+                self._viewer_3d.clear_preview()
+
+        dialog.set_preview_callback(_preview)
+
+        if dialog.exec():
+            values = dialog.get_values()
+            normal = values["mirror_plane_normal"]
+            origin = values["mirror_plane_origin"]
+            keep_original = values["keep_original"]
+
+            try:
+                mirrored = self._kernel.mirror(body.geometry, normal, origin)
+            except Exception as exc:
+                logger.exception(f"Mirror failed: {exc}")
+                QMessageBox.critical(
+                    self, "Mirror Failed", f"Could not mirror the body: {exc}"
+                )
+                return
+            if mirrored is None:
+                QMessageBox.critical(
+                    self, "Mirror Failed", "The mirror operation produced no geometry."
+                )
+                return
+
+            if keep_original:
+                try:
+                    result_geom = self._kernel.boolean_union(body.geometry, mirrored)
+                except Exception as exc:
+                    logger.exception(f"Mirror union failed: {exc}")
+                    QMessageBox.critical(
+                        self, "Mirror Failed",
+                        f"Could not union original with mirror: {exc}"
+                    )
+                    return
+                if result_geom is None:
+                    QMessageBox.critical(
+                        self, "Mirror Failed", "Union produced no geometry."
+                    )
+                    return
+            else:
+                result_geom = mirrored
+
+            # Record the operation in the feature history.
+            features = _ensure_feature_history(body)
+            if not features and body.geometry is not None:
+                features.append(Feature(operation="base", geometry=body.geometry))
+            features.append(
+                Feature(
+                    operation="mirror",
+                    mirror_plane_origin=origin,
+                    mirror_plane_normal=normal,
+                    keep_original=keep_original,
+                )
+            )
+
+            body.geometry = result_geom
+            body.needs_update = False
+            body.modified_at = datetime.now()
+            self._mark_dirty()
+
+            # Re-render the body in place.
+            if body.render_object is not None:
+                self._viewer_3d.remove_mesh(body.render_object)
+            new_shape = self._kernel._get_shape(body.geometry)
+            body.render_object = self._viewer_3d.show_shape(
+                new_shape, body.color, body.name
+            )
+
+            self._refresh_lists()
+            self._update_component_thumbnail(self._get_active_component_index())
+            keep_msg = " (keep original)" if keep_original else ""
+            self.statusBar().showMessage(f"Mirror applied{keep_msg}", 5000)
+            logger.info(f"Applied mirror to '{body.name}'{keep_msg}")
+
+        # Preview already cleared by the dialog's hideEvent; clear again
+        # in case the dialog was rejected programmatically.
+        self._viewer_3d.clear_preview()
+
     # ─── Offset sketch ─────────────────────────────────────────────────────
 
     @staticmethod
@@ -4897,8 +5052,6 @@ class MainWindow(QMainWindow):
             5000,
         )
 
-    def _pattern_array_placeholder(self):
-        pass
 
     def _add_sketch_to_component(self):
         logger.info("=== ADD SKETCH TO COMPONENT ===")
diff --git a/src/fluency/ui/sketch_widget.py b/src/fluency/ui/sketch_widget.py
index f0570dc..d5adaf1 100644
--- a/src/fluency/ui/sketch_widget.py
+++ b/src/fluency/ui/sketch_widget.py
@@ -863,19 +863,17 @@ class Sketch2DWidget(QWidget):
         constraint multi-select, then emits ``constrain_done`` so the
         toolbar buttons uncheck themselves.
         """
-        if not self._is_drawing_tool_active():
-            return
-        self._mode = None
+        was_active = self._is_drawing_tool_active()
         self._draw_buffer = []
         self._dynamic_line_end = None
         self._selected_entities = []
         self._hovered_constraint_idx = -1
         self._arc_accum_sweep = 0.0
         self._arc_prev_angle = None
-        # Invalidate any pending dimension-input prompt so the value
-        # dialog (if one is open elsewhere) doesn't latch onto stale state.
         self._pending_distance_val = None
-        self.constrain_done.emit()
+        if was_active:
+            self._mode = None
+            self.constrain_done.emit()
         self.update()
 
     def set_construct_mode(self, enabled: bool):
@@ -930,13 +928,12 @@ class Sketch2DWidget(QWidget):
 
     # ─── Snapping ─────────────────────────────────────────────────────────
 
-    def _find_nearest_point(self, pos: QPoint, max_distance: int = 15) -> Optional[QPoint]:
-        # Delegates to _find_nearest_point_entity so the position snap and
+    def _find_nearest_point(self, pos: QPoint, max_distance: int = 15, exclude_ids: Optional[set[int]] = None) -> Optional[QPoint]:
         # the constraint target ALWAYS agree — previously this loop ignored
         # underlay visibility, so a hidden underlay corner would snap the
         # cursor position while the entity lookup returned None and no
         # coincident constraint was created (silent disconnect).
-        entity = self._find_nearest_point_entity(pos, max_distance)
+        entity = self._find_nearest_point_entity(pos, max_distance, exclude_ids=exclude_ids)
         if entity is None:
             return None
         xy = self._flat_xy(entity.geometry)
@@ -946,7 +943,7 @@ class Sketch2DWidget(QWidget):
         return QPoint(int(round(x)), int(round(y)))
 
     def _find_nearest_point_entity(
-        self, pos: QPoint, max_distance: int = 15
+        self, pos: QPoint, max_distance: int = 15, exclude_ids: Optional[set[int]] = None
     ) -> Optional[OCCSketchEntity]:
         """Find the nearest point entity to a screen position.
 
@@ -962,6 +959,8 @@ class Sketch2DWidget(QWidget):
         for entity in self._points:
             if self._is_external(entity) and not self._underlay_visible:
                 continue
+            if exclude_ids and entity.id in exclude_ids:
+                continue
             xy = self._flat_xy(entity.geometry)
             if xy is None:
                 continue
@@ -1066,7 +1065,7 @@ class Sketch2DWidget(QWidget):
             return end
         return QPoint(start.x(), end.y())
 
-    def _apply_all_snaps(self, pos: QPoint, start: Optional[QPoint] = None) -> QPoint:
+    def _apply_all_snaps(self, pos: QPoint, start: Optional[QPoint] = None, exclude_ids: Optional[set[int]] = None) -> QPoint:
         result = pos
         # Reset auto-constraint tracking
         self._snap_point_target = None
@@ -1074,10 +1073,16 @@ class Sketch2DWidget(QWidget):
         self._snap_horizontal = False
         self._snap_vertical = False
 
-        point_snap = self._find_nearest_point(pos)
+        point_snap = self._find_nearest_point(pos, exclude_ids=exclude_ids)
         if point_snap:
             self._snap_point_target = self._find_nearest_point_entity(pos)
             return self._world_to_screen(point_snap)
+        # When exclude_ids is active (constraint multi-select), don't fall
+        # through to midpoint / line snap — those redirect the click to a
+        # position the handler's point lookup won't find.  The handler uses
+        # its own world-space entity lookup with the same exclude set.
+        if exclude_ids:
+            return result
         if self._snap_mode.get("mpoint", False):
             mid_snap = self._find_midpoint_snap(pos)
             if mid_snap:
@@ -1240,7 +1245,7 @@ class Sketch2DWidget(QWidget):
 
     # ─── Solver helpers ───────────────────────────────────────────────────
 
-    def _get_point_entity_at(self, world_pos: QPoint) -> Optional[OCCSketchEntity]:
+    def _get_point_entity_at(self, world_pos: QPoint, exclude_ids: Optional[set[int]] = None) -> Optional[OCCSketchEntity]:
         """Find nearest point entity to world position.
 
         External (underlay) points are pickable when the underlay is visible
@@ -1261,6 +1266,8 @@ class Sketch2DWidget(QWidget):
         for entity in self._points:
             if self._is_external(entity) and not self._underlay_visible:
                 continue
+            if exclude_ids and entity.id in exclude_ids:
+                continue
             xy = self._flat_xy(entity.geometry)
             if xy is None:
                 continue
@@ -1278,8 +1285,44 @@ class Sketch2DWidget(QWidget):
                     best, best_dist = entity, dist
         return best if best is not None else ref_best
 
+    def _get_point_entity_at_fallback(
+        self, world_pos: QPoint, exclude_ids: Optional[set[int]] = None
+    ) -> Optional[OCCSketchEntity]:
+        """Same as :meth:`_get_point_entity_at` but with 3× tolerance.
+
+        Used by the distance constraint handler when the standard lookup fails
+        during multi-select — the snap may not have fired (the excluded entity
+        was the only one within screen range), so ``world_snapped`` is the raw
+        click position which can be further from the intended target than the
+        snapped position would have been.
+        """
+        best: Optional[OCCSketchEntity] = None
+        best_dist = float("inf")
+        ref_best: Optional[OCCSketchEntity] = None
+        ref_best_dist = float("inf")
+        tolerance = self._pick_tolerance_world(30)
+        for entity in self._points:
+            if self._is_external(entity) and not self._underlay_visible:
+                continue
+            if exclude_ids and entity.id in exclude_ids:
+                continue
+            xy = self._flat_xy(entity.geometry)
+            if xy is None:
+                continue
+            x, y = xy
+            dist = math.sqrt((world_pos.x() - x) ** 2 + (world_pos.y() - y) ** 2)
+            if dist >= tolerance:
+                continue
+            if self._is_external(entity) or self._is_centerline(entity):
+                if dist < ref_best_dist:
+                    ref_best, ref_best_dist = entity, dist
+            else:
+                if dist < best_dist:
+                    best, best_dist = entity, dist
+        return best if best is not None else ref_best
+
     def _get_line_entity_at(
-        self, world_pos: QPoint
+        self, world_pos: QPoint, exclude_ids: Optional[set[int]] = None
     ) -> Optional[Tuple[OCCSketchEntity, OCCSketchEntity]]:
         """Find a line near the given world position.
 
@@ -1307,6 +1350,12 @@ class Sketch2DWidget(QWidget):
             is_ext = bool(line_ent is not None and self._is_external(line_ent))
             if is_ext and not self._underlay_visible:
                 continue
+            # NOTE: exclude_ids is accepted for API consistency but NOT applied
+            # here — it contains POINT ids (the already-selected entity for
+            # multi-click constraint tools).  Filtering lines by their endpoint
+            # ids would prevent the user from picking a line that shares the
+            # selected point, which is a valid operation for point-on-line /
+            # midpoint / distance constraints.
             if p1_ent.geometry and p2_ent.geometry:
                 x1, y1 = p1_ent.geometry
                 x2, y2 = p2_ent.geometry
@@ -2201,9 +2250,15 @@ class Sketch2DWidget(QWidget):
                     self.update()
                     return
 
+            # Exclude already-selected entities from snap/lookup during constraint multi-select
+            # so the user can pick a second entity distinct from the first.
+            _exclude_ids: Optional[set[int]] = None
+            if self._mode and self._mode.startswith("constrain_") and self._selected_entities:
+                _exclude_ids = {e.id for e in self._selected_entities}
             snapped_pos = self._apply_all_snaps(
                 event.pos(),
                 self._world_to_screen(self._draw_buffer[0]) if self._draw_buffer else None,
+                exclude_ids=_exclude_ids,
             )
             world_snapped = (
                 self._screen_to_world(snapped_pos) if snapped_pos != event.pos() else world_pos
@@ -2222,23 +2277,23 @@ class Sketch2DWidget(QWidget):
             elif self._mode == "select":
                 self._handle_select_click(world_snapped)
             elif self._mode == "constrain_coincident":
-                self._handle_constraint_coincident(world_snapped)
+                self._handle_constraint_coincident(world_snapped, exclude_ids=_exclude_ids)
             elif self._mode == "constrain_horizontal":
                 self._handle_constraint_horizontal(world_snapped)
             elif self._mode == "constrain_vertical":
                 self._handle_constraint_vertical(world_snapped)
             elif self._mode == "constrain_distance":
-                self._handle_constraint_distance(world_snapped)
+                self._handle_constraint_distance(world_snapped, exclude_ids=_exclude_ids)
             elif self._mode == "constrain_midpoint":
-                self._handle_constraint_midpoint(world_snapped)
+                self._handle_constraint_midpoint(world_snapped, exclude_ids=_exclude_ids)
             elif self._mode == "constrain_perpendicular":
                 self._handle_constraint_perpendicular(world_snapped)
             elif self._mode == "constrain_parallel":
                 self._handle_constraint_parallel(world_snapped)
             elif self._mode == "constrain_ptline":
-                self._handle_constraint_ptline(world_snapped)
+                self._handle_constraint_ptline(world_snapped, exclude_ids=_exclude_ids)
             elif self._mode == "constrain_symmetric":
-                self._handle_constraint_symmetric(world_snapped)
+                self._handle_constraint_symmetric(world_snapped, exclude_ids=_exclude_ids)
             elif self._mode == "constrain_diameter":
                 self._handle_constraint_diameter(world_snapped)
 
@@ -3350,10 +3405,13 @@ class Sketch2DWidget(QWidget):
 
     # ─── Constraint handlers (with solver calls) ──────────────────────────
 
-    def _handle_constraint_coincident(self, world_pos: QPoint):
-        ent = self._get_point_entity_at(world_pos)
+    def _handle_constraint_coincident(self, world_pos: QPoint, exclude_ids: Optional[set[int]] = None):
+        ent = self._get_point_entity_at(world_pos, exclude_ids=exclude_ids)
         if ent is None:
             return
+        if ent in self._selected_entities:
+            self.update()
+            return
         self._selected_entities.append(ent)
         if len(self._selected_entities) >= 2:
             e1, e2 = self._selected_entities[:2]
@@ -3406,7 +3464,6 @@ class Sketch2DWidget(QWidget):
         line_ent = self._find_line_sketch_entity(p1_ent, p2_ent)
         if line_ent is None:
             return
-        # Save state before adding constraint
         if self._undo_manager:
             self._undo_manager.save_state()
         if self._sketch:
@@ -3423,19 +3480,20 @@ class Sketch2DWidget(QWidget):
         self.constrain_done.emit()
         self.update()
 
-    def _handle_constraint_distance(self, world_pos: QPoint):
-        point_ent = self._get_point_entity_at(world_pos)
+    def _handle_constraint_distance(self, world_pos: QPoint, exclude_ids: Optional[set[int]] = None):
+        point_ent = self._get_point_entity_at(world_pos, exclude_ids=exclude_ids)
+        if point_ent is None:
+            # The snap may not have fired (excluded entity was the only one
+            # within screen range, or the standard tolerance is too tight after
+            # a viewport change like re-projecting a face).  Retry with 3×.
+            point_ent = self._get_point_entity_at_fallback(world_pos, exclude_ids=exclude_ids)
         if point_ent:
-            # Clicking the same point twice would create a point-to-itself
-            # distance which the solver can never satisfy for a non-zero
-            # value — ignore the repeat so the user can reposition instead.
             if point_ent in self._selected_entities:
                 self.update()
                 return
-            # Point clicked: collect points; constraint applied after 2nd point.
             self._selected_entities.append(point_ent)
         else:
-            line_hit = self._get_line_entity_at(world_pos)
+            line_hit = self._get_line_entity_at(world_pos, exclude_ids=exclude_ids)
             if line_hit:
                 p1_ent, p2_ent = line_hit
                 line_ent = self._find_line_sketch_entity(p1_ent, p2_ent)
@@ -3517,12 +3575,12 @@ class Sketch2DWidget(QWidget):
             self.constrain_done.emit()
         self.update()
 
-    def _handle_constraint_midpoint(self, world_pos: QPoint):
-        point_ent = self._get_point_entity_at(world_pos)
+    def _handle_constraint_midpoint(self, world_pos: QPoint, exclude_ids: Optional[set[int]] = None):
+        point_ent = self._get_point_entity_at(world_pos, exclude_ids=exclude_ids)
         if point_ent and not self._selected_entities:
             self._selected_entities.append(point_ent)
         elif self._selected_entities:
-            line_hit = self._get_line_entity_at(world_pos)
+            line_hit = self._get_line_entity_at(world_pos, exclude_ids=exclude_ids)
             if line_hit:
                 p1_ent, p2_ent = line_hit
                 line_ent = self._find_line_sketch_entity(p1_ent, p2_ent)
@@ -3593,13 +3651,13 @@ class Sketch2DWidget(QWidget):
             self.constrain_done.emit()
         self.update()
 
-    def _handle_constraint_ptline(self, world_pos: QPoint):
+    def _handle_constraint_ptline(self, world_pos: QPoint, exclude_ids: Optional[set[int]] = None):
         """Point-on-line coincident (point on line)."""
-        point_ent = self._get_point_entity_at(world_pos)
+        point_ent = self._get_point_entity_at(world_pos, exclude_ids=exclude_ids)
         if point_ent and not self._selected_entities:
             self._selected_entities.append(point_ent)
         elif self._selected_entities:
-            line_hit = self._get_line_entity_at(world_pos)
+            line_hit = self._get_line_entity_at(world_pos, exclude_ids=exclude_ids)
             if line_hit:
                 p1_ent, p2_ent = line_hit
                 line_ent = self._find_line_sketch_entity(p1_ent, p2_ent)
@@ -3616,11 +3674,11 @@ class Sketch2DWidget(QWidget):
                 self.constrain_done.emit()
         self.update()
 
-    def _handle_constraint_symmetric(self, world_pos: QPoint):
+    def _handle_constraint_symmetric(self, world_pos: QPoint, exclude_ids: Optional[set[int]] = None):
         """Symmetric constraint: select entity1, entity2, then mirror line."""
         # Click 3: mirror line
         if len(self._selected_entities) == 2:
-            line_hit = self._get_line_entity_at(world_pos)
+            line_hit = self._get_line_entity_at(world_pos, exclude_ids=exclude_ids)
             if line_hit:
                 p1_ent, p2_ent = line_hit
                 mirror_line = self._find_line_sketch_entity(p1_ent, p2_ent)
@@ -3642,8 +3700,11 @@ class Sketch2DWidget(QWidget):
             self.update()
             return
         # Clicks 1-2: select point entities
-        point_ent = self._get_point_entity_at(world_pos)
+        point_ent = self._get_point_entity_at(world_pos, exclude_ids=exclude_ids)
         if point_ent:
+            if point_ent in self._selected_entities:
+                self.update()
+                return
             self._selected_entities.append(point_ent)
             n_selected = len(self._selected_entities)
             if n_selected < 2: