feat(statusbar): isolate / hide objects with status pill

Add a hidden-entity set to the scene that the tessellation visibility
test skips, so hidden objects neither render nor hit-test. New commands
ISOLATEOBJECTS (show only the selection), HIDEOBJECTS (hide the
selection) and UNISOLATEOBJECTS (restore). An ISO status pill lights up
while anything is hidden and restores everything on click.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/commands.rs

@@ -332,6 +332,44 @@ impl OpenCADStudio {
                 }
             }
 
+            // ISOLATEOBJECTS — hide every object except the current selection
+            "ISOLATEOBJECTS" => {
+                if self.tabs[i].scene.selected.is_empty() {
+                    self.command_line
+                        .push_error("ISOLATEOBJECTS: select the objects to isolate first.");
+                } else {
+                    let n = self.tabs[i].scene.selected.len();
+                    self.tabs[i].scene.isolate_selected();
+                    self.command_line.push_info(&format!(
+                        "Isolated {n} object(s). UNISOLATEOBJECTS to restore."
+                    ));
+                }
+            }
+
+            // HIDEOBJECTS — hide the current selection
+            "HIDEOBJECTS" => {
+                if self.tabs[i].scene.selected.is_empty() {
+                    self.command_line
+                        .push_error("HIDEOBJECTS: select the objects to hide first.");
+                } else {
+                    let n = self.tabs[i].scene.selected.len();
+                    self.tabs[i].scene.hide_selected();
+                    self.command_line
+                        .push_info(&format!("Hid {n} object(s). UNISOLATEOBJECTS to restore."));
+                }
+            }
+
+            // UNISOLATEOBJECTS — bring back everything hidden by Isolate / Hide
+            "UNISOLATEOBJECTS" => {
+                if self.tabs[i].scene.is_isolation_active() {
+                    self.tabs[i].scene.end_isolation();
+                    self.command_line
+                        .push_info("Isolation ended — all objects shown.");
+                } else {
+                    self.command_line.push_info("No hidden objects.");
+                }
+            }
+
             // LAYUNISO — restore all layers that were turned off by LAYISO (turn all on)
             "LAYUNISO" => {
                 self.push_undo_snapshot(i, "LAYUNISO");

src/app/view.rs

@@ -1159,6 +1159,7 @@ impl OpenCADStudio {
                         self.clean_screen,
                         tab.scene.document.header.insertion_units,
                         self.units_popup_open,
+                        tab.scene.is_isolation_active(),
                         &self.statusbar_config,
                     )
                 })

src/scene/mod.rs

@@ -549,6 +549,10 @@ pub struct Scene {
     pub document: CadDocument,
     /// Currently selected entity handles.
     pub selected: HashSet<Handle>,
+    /// Entity handles hidden by Isolate / Hide. Empty = nothing hidden.
+    /// `tessellate_block`'s visibility test skips these, so they neither
+    /// render nor hit-test until isolation ends.
+    pub hidden: HashSet<Handle>,
     /// In-progress preview wires while a command is active (rubber-band + object ghosts).
     pub preview_wires: Vec<WireModel>,
     /// Committed-segment wire drawn during multi-point commands (normal colour).
@@ -693,6 +697,7 @@ impl Scene {
             selection: Rc::new(RefCell::new(SelectionState::default())),
             document: CadDocument::new(),
             selected: HashSet::new(),
+            hidden: HashSet::new(),
             preview_wires: vec![],
             interim_wire: None,
             camera_generation: 0,
@@ -1316,6 +1321,48 @@ impl Scene {
             .count()
     }
 
+    /// True when any entities are hidden by Isolate / Hide.
+    pub fn is_isolation_active(&self) -> bool {
+        !self.hidden.is_empty()
+    }
+
+    /// Hide every drawable entity except the current selection (Isolate).
+    pub fn isolate_selected(&mut self) {
+        if self.selected.is_empty() {
+            return;
+        }
+        let keep = self.selected.clone();
+        self.hidden = self
+            .document
+            .entities()
+            .map(|e| e.common().handle)
+            .filter(|h| !h.is_null() && !keep.contains(h))
+            .collect();
+        self.selected.clear();
+        self.bump_geometry();
+    }
+
+    /// Hide the current selection (Hide Objects).
+    pub fn hide_selected(&mut self) {
+        if self.selected.is_empty() {
+            return;
+        }
+        for h in self.selected.iter().copied() {
+            self.hidden.insert(h);
+        }
+        self.selected.clear();
+        self.bump_geometry();
+    }
+
+    /// Clear isolation — bring every hidden entity back (End Isolation).
+    pub fn end_isolation(&mut self) {
+        if self.hidden.is_empty() {
+            return;
+        }
+        self.hidden.clear();
+        self.bump_geometry();
+    }
+
     /// True if any currently selected entity is a Viewport.
     /// Used to enable the scale picker when a viewport is selected in paper space.
     pub fn has_selected_viewport(&self) -> bool {
@@ -1869,6 +1916,10 @@ impl Scene {
             if c.invisible {
                 return false;
             }
+            // Isolate / Hide: skip entities the user has hidden.
+            if !self.hidden.is_empty() && self.hidden.contains(&c.handle) {
+                return false;
+            }
             // Block/BlockEnd are block-defn sentinels, not drawable geometry.
             // Without this skip they fall through to fallback_geometry's `_`
             // arm and emit a 1-unit phantom segment at world_offset that

src/ui/statusbar.rs

@@ -59,6 +59,8 @@ impl StatusBar {
         insertion_units: i16,
         // True while the drawing-units picker is open.
         units_popup_open: bool,
+        // True when objects are hidden by Isolate / Hide.
+        isolation_active: bool,
         // Which pills the user has chosen to show on the bar.
         config: &'a StatusBarConfig,
     ) -> Element<'a, Message> {
@@ -173,6 +175,16 @@ impl StatusBar {
                 "Drawing Units (INSUNITS)\nClick to change",
             ));
         }
+        if vis(StatusPill::Isolate) {
+            right_status = right_status.push(tip(
+                toggle_pill(
+                    "ISO",
+                    isolation_active,
+                    Message::Command("UNISOLATEOBJECTS".into()),
+                ),
+                "Isolate Objects\nISOLATEOBJECTS / HIDEOBJECTS to hide; click to restore",
+            ));
+        }
         if vis(StatusPill::Vp) && !vp_label.is_empty() {
             right_status = right_status.push(tip(
                 status_pill(vp_label).into(),

src/ui/statusbar_config.rs

@@ -23,6 +23,7 @@ pub enum StatusPill {
     Space,
     Scale,
     Units,
+    Isolate,
     Vp,
     CleanScreen,
 }
@@ -43,6 +44,7 @@ impl StatusPill {
         StatusPill::Space,
         StatusPill::Scale,
         StatusPill::Units,
+        StatusPill::Isolate,
         StatusPill::Vp,
         StatusPill::CleanScreen,
     ];
@@ -62,6 +64,7 @@ impl StatusPill {
             StatusPill::Space => "space",
             StatusPill::Scale => "scale",
             StatusPill::Units => "units",
+            StatusPill::Isolate => "isolate",
             StatusPill::Vp => "vp",
             StatusPill::CleanScreen => "cleanscreen",
         }
@@ -82,6 +85,7 @@ impl StatusPill {
             StatusPill::Space => "Model/Paper Space",
             StatusPill::Scale => "Annotation Scale",
             StatusPill::Units => "Drawing Units",
+            StatusPill::Isolate => "Isolate Objects",
             StatusPill::Vp => "Viewport Count",
             StatusPill::CleanScreen => "Clean Screen",
         }