Merge PR #322: perf — responsive large copy/paste + point picking

External contributor sLuCHa (sLuCHaa). Gates O(k²) snap intersection
passes, O(1) handle lookups in preview, bbox paste anchor/ghost,
count-only properties panel for huge selections, incremental paste mesh.

src/app/command_driver.rs

@@ -2085,7 +2085,12 @@ impl OpenCADStudio {
             })
             .collect();
         self.merge_clipboard_ext_objects(i, &by_index);
-        self.tabs[i].scene.populate_meshes_from_document();
+        // Incremental: `add_entity` already tessellated every pasted top-level
+        // solid, and existing document solids are still cached — so only newly
+        // introduced block-definition solids need building. The full rebuild
+        // would clear and re-tessellate the entire document (every solid in the
+        // drawing) on each paste, which is what made a large paste stall.
+        self.tabs[i].scene.populate_missing_meshes_from_document();
         by_index
     }
 

src/app/commands/blocks.rs

@@ -70,8 +70,9 @@ impl OpenCADStudio {
                         .iter()
                         .filter_map(|&h| self.tabs[i].scene.document.get_entity(h).cloned())
                         .collect();
-                    self.clipboard_centroid = super::super::helpers::entities_centroid(
-                        &self.tabs[i].scene.wire_models_for(&handles),
+                    self.clipboard_centroid = super::super::helpers::entities_centroid_by_bbox(
+                        &self.tabs[i].scene.document,
+                        &handles,
                     );
                     self.clipboard = entities;
                     self.clipboard_deps = super::super::ClipboardDeps::capture(
@@ -158,8 +159,9 @@ impl OpenCADStudio {
                         .iter()
                         .filter_map(|&h| self.tabs[i].scene.document.get_entity(h).cloned())
                         .collect();
-                    self.clipboard_centroid = super::super::helpers::entities_centroid(
-                        &self.tabs[i].scene.wire_models_for(&handles),
+                    self.clipboard_centroid = super::super::helpers::entities_centroid_by_bbox(
+                        &self.tabs[i].scene.document,
+                        &handles,
                     );
                     let count = entities.len();
                     self.clipboard = entities;

src/app/helpers.rs

@@ -1,4 +1,3 @@
-use crate::scene::WireModel;
 use crate::ui::overlay::GridPlane;
 use acadrust::tables::Ucs;
 
@@ -253,28 +252,27 @@ pub(super) fn polar_constrain_near(
 
 // ── Clipboard / selection helpers ──────────────────────────────────────────
 
-/// Compute the centroid of a set of wire models (average of all points).
-pub(super) fn entities_centroid(wires: &[WireModel]) -> glam::DVec3 {
-    // Reconstruct each vertex's absolute f64 from the double-single high/low
-    // pair and accumulate in f64: summing the f32 `points` alone at UTM scale
-    // (~5.7e6) both quantizes each term ~0.5 m and loses low bits across the
-    // running total, drifting the paste base / block base metres off.
+/// Cheap copy/paste anchor: the mean of each entity's bounding-box centre.
+/// Replaces averaging every tessellated wire vertex, which cost O(total
+/// geometry) and stalled a whole-drawing copy. The anchor only sets which point
+/// of the selection sits under the cursor, so a per-entity bbox centre is an
+/// equally valid, far cheaper origin.
+pub(super) fn entities_centroid_by_bbox(
+    doc: &acadrust::CadDocument,
+    handles: &[acadrust::Handle],
+) -> glam::DVec3 {
     let mut sum = glam::DVec3::ZERO;
     let mut count = 0usize;
-    for w in wires {
-        for (i, p) in w.points.iter().enumerate() {
-            // Wire models carry NaN points as separators between disjoint
-            // segments; summing them poisons the whole centroid into NaN,
-            // which then makes every paste base point NaN. (#129)
-            if !p[0].is_finite() || !p[1].is_finite() || !p[2].is_finite() {
-                continue;
-            }
-            let l = w.points_low.get(i).copied().unwrap_or([0.0; 3]);
-            sum += glam::DVec3::new(
-                p[0] as f64 + l[0] as f64,
-                p[1] as f64 + l[1] as f64,
-                p[2] as f64 + l[2] as f64,
-            );
+    for &h in handles {
+        let Some(e) = doc.get_entity(h) else { continue };
+        let bb = e.as_entity().bounding_box();
+        let c = glam::DVec3::new(
+            (bb.min.x + bb.max.x) * 0.5,
+            (bb.min.y + bb.max.y) * 0.5,
+            (bb.min.z + bb.max.z) * 0.5,
+        );
+        if c.x.is_finite() && c.y.is_finite() && c.z.is_finite() {
+            sum += c;
             count += 1;
         }
     }

src/app/properties.rs

@@ -5,6 +5,11 @@ use crate::scene::view::dispatch;
 use crate::ui;
 use acadrust::{EntityType, Handle};
 
+/// Above this many selected objects the Properties panel skips per-entity
+/// property aggregation (which is O(n) per row, plus an O(n²) group filter) and
+/// shows a count-only summary instead. Bulk edits still go through the ribbon.
+const MAX_PROP_AGGREGATE: usize = 2_000;
+
 impl OpenCADStudio {
     /// Rebuild the PropertiesPanel from the current entity selection.
     /// Preserves UI state (open pickers, edit buffer) across refreshes.
@@ -432,6 +437,23 @@ impl OpenCADStudio {
                         ..Default::default()
                     }
                 }
+                // Property aggregation is O(n) per row plus an O(n²) group filter
+                // (`group.handles.contains` scans per entity), stalling the rebuild
+                // for seconds at tens of thousands of objects. Above the cap show a
+                // count-only panel; bulk edits still go through the ribbon.
+                n if n > MAX_PROP_AGGREGATE => ui::PropertiesPanel {
+                    title: format!("{} objects selected", n),
+                    layer_combo: iced::widget::combo_box::State::new(layer_names.clone()),
+                    linetype_combo: iced::widget::combo_box::State::new(linetype_items.clone()),
+                    lineweight_combo: iced::widget::combo_box::State::new(
+                        ui::properties::lw_options(),
+                    ),
+                    hatch_pattern_combo: iced::widget::combo_box::State::new(
+                        crate::scene::model::hatch_patterns::names(),
+                    ),
+                    linetype_items,
+                    ..Default::default()
+                },
                 _ => {
                     let groups = build_selection_groups(&selected);
                     let active_group = selected_group

src/modules/draw/clipboard/paste.rs

@@ -22,15 +22,78 @@ use crate::command::{CadCommand, CmdResult};
 use crate::scene::model::wire_model::WireModel;
 
 pub struct PasteCommand {
-    /// Wire models of the clipboard entities (used for preview).
+    /// Wire models of the clipboard entities (used for the ghost preview).
+    /// Emptied when `bbox_wire` is used, so a huge clipboard isn't kept twice.
     wires: Vec<WireModel>,
+    /// Lightweight bounding-box outline that replaces `wires` for very large
+    /// clipboards. `on_preview_wires` runs every mouse move and translates every
+    /// point of the ghost; for a whole-drawing paste that is O(hundreds of
+    /// thousands) per frame and freezes placement. Above a point budget we ghost
+    /// just this 5-point rectangle instead — O(1) per frame — the same way
+    /// AutoCAD rubber-bands a box for a huge selection. `None` = ghost the full
+    /// wires.
+    bbox_wire: Option<WireModel>,
     /// Centroid of the clipboard entities (offset origin for translation).
     centroid: Vec3,
 }
 
 impl PasteCommand {
+    /// `on_preview_wires` clones and re-uploads the whole ghost every cursor
+    /// move, so its cost scales with the wire count and the total point count.
+    /// Past either budget the per-move work floods the event loop, so switch to
+    /// a bounding-box outline; below them the full ghost still shows.
+    const MAX_PREVIEW_WIRES: usize = 20_000;
+    const MAX_PREVIEW_POINTS: usize = 300_000;
+
     pub fn new(wires: Vec<WireModel>, centroid: Vec3) -> Self {
-        Self { wires, centroid }
+        let total_points: usize = wires.iter().map(|w| w.points.len()).sum();
+        let too_heavy =
+            wires.len() > Self::MAX_PREVIEW_WIRES || total_points > Self::MAX_PREVIEW_POINTS;
+        if too_heavy {
+            if let Some(bbox_wire) = Self::bbox_outline(&wires) {
+                // Drop the full wires — the box is all the ghost needs now.
+                return Self { wires: Vec::new(), bbox_wire: Some(bbox_wire), centroid };
+            }
+        }
+        Self { wires, bbox_wire: None, centroid }
+    }
+
+    /// Build a closed rectangle outline around the XY extent of `wires`, in the
+    /// same world coordinates so the standard `translated(delta)` shift applies.
+    /// Uses the double-single `points + points_low` sum so the box stays precise
+    /// at UTM-scale coordinates. Returns `None` when there are no points.
+    fn bbox_outline(wires: &[WireModel]) -> Option<WireModel> {
+        let mut min = [f64::INFINITY; 3];
+        let mut max = [f64::NEG_INFINITY; 3];
+        let mut any = false;
+        for w in wires {
+            for (i, p) in w.points.iter().enumerate() {
+                let lo = w.points_low.get(i).copied().unwrap_or([0.0; 3]);
+                for k in 0..3 {
+                    let v = p[k] as f64 + lo[k] as f64;
+                    min[k] = min[k].min(v);
+                    max[k] = max[k].max(v);
+                }
+                any = true;
+            }
+        }
+        if !any {
+            return None;
+        }
+        let z = min[2];
+        let pts = vec![
+            [min[0], min[1], z],
+            [max[0], min[1], z],
+            [max[0], max[1], z],
+            [min[0], max[1], z],
+            [min[0], min[1], z],
+        ];
+        Some(WireModel::solid_f64(
+            "paste_bbox".into(),
+            pts,
+            WireModel::CYAN,
+            false,
+        ))
     }
 }
 
@@ -55,8 +118,13 @@ impl CadCommand for PasteCommand {
         vec![]
     }
 
-    fn on_preview_wires(&mut self, pt: DVec3) -> Vec<WireModel> { let pt = pt.as_vec3();
+    fn on_preview_wires(&mut self, pt: DVec3) -> Vec<WireModel> {
+        let pt = pt.as_vec3();
         let delta = pt - self.centroid;
+        // Large clipboard: ghost just the bounding box — O(1) per frame.
+        if let Some(bbox) = &self.bbox_wire {
+            return vec![bbox.translated(delta)];
+        }
         self.wires.iter().map(|w| w.translated(delta)).collect()
     }
 }

src/scene/preview.rs

@@ -26,7 +26,7 @@ impl Scene {
         handles
             .iter()
             .flat_map(|h| {
-                match self.document.entities().find(|e| e.common().handle == *h) {
+                match self.document.get_entity(*h) {
                     // Hatches carry no outline in the normal wire set, but an
                     // edit preview (move / copy / array / grip-drag) needs to
                     // show the shape following the cursor. Build a live boundary
@@ -54,7 +54,7 @@ impl Scene {
         let mut plain: Vec<WireModel> = Vec::new();
         let mut texts: Vec<(WireModel, glam::DVec3)> = Vec::new();
         for h in handles {
-            let Some(e) = self.document.entities().find(|e| e.common().handle == *h) else {
+            let Some(e) = self.document.get_entity(*h) else {
                 continue;
             };
             if matches!(e, EntityType::Text(_)) {

src/snap.rs

@@ -878,6 +878,19 @@ impl Snapper {
                 && cursor_world.y - r <= wire.aabb[3] as f64
         };
 
+        // The per-wire snaps below skip out-of-aperture wires via `wire_in_range`,
+        // so they stay O(n) and snap at any zoom. Intersection / ApparentIntersection
+        // instead compare pairs of in-range segments — O(k²) — which hangs when the
+        // aperture spans the whole drawing. Count the in-range wires once and gate
+        // only those pairwise passes; the single-wire snaps always run.
+        const MAX_PAIRWISE_CANDIDATES: usize = 1_500;
+        let allow_pairwise = wires
+            .iter()
+            .filter(|w| wire_in_range(w))
+            .take(MAX_PAIRWISE_CANDIDATES + 1)
+            .count()
+            <= MAX_PAIRWISE_CANDIDATES;
+
         let mut try_pt = |world: glam::DVec3, snap_type: SnapType| {
             let screen = world_to_screen(world, view_rot, eye, bounds);
             if !in_bounds(screen) {
@@ -1018,8 +1031,8 @@ impl Snapper {
             }
         }
 
-        // ── Intersection — segment-segment intersections ──────────
-        if self.is_on(SnapType::Intersection) {
+        // ── Intersection — segment-segment intersections (pairwise, gated) ──
+        if self.is_on(SnapType::Intersection) && allow_pairwise {
             for i in 0..wires.len() {
                 if !wire_in_range(&wires[i]) {
                     continue;
@@ -1169,9 +1182,9 @@ impl Snapper {
             }
         }
 
-        // ── Apparent Intersection — screen-space intersections ─────────────
+        // ── Apparent Intersection — screen-space intersections (pairwise, gated) ──
         // L: pre-project each in-range wire's points to screen once, not once per segment pair.
-        if self.is_on(SnapType::ApparentIntersection) {
+        if self.is_on(SnapType::ApparentIntersection) && allow_pairwise {
             let screen_pts: Vec<Option<Vec<Point>>> = wires
                 .iter()
                 .map(|w| {