From c333889fc016eb6abe203b0f679cb627c172b358 Mon Sep 17 00:00:00 2001
From: bherbruck <brennen.herbruck@gmail.com>
Date: Tue, 13 Oct 2026 19:45:18 -0400
Subject: [PATCH] Open large designs faster: index the previous bodies by name
 after each feature (#912)

After each feature the bodies before it are indexed by name once (first match first, as the linear searches were), feature components come from a map built once per evaluation, and Body::same compares shared face sources, paint and split lines by pointer first.
---
 crates/doc/src/eval.rs    | 27 ++++++++++++++++++++++-----
 crates/kernel/src/body.rs | 15 ++++++++++++---
 2 files changed, 34 insertions(+), 8 deletions(-)

diff --git a/crates/doc/src/eval.rs b/crates/doc/src/eval.rs
index 8a5ca8c5..1ab8c824 100644
--- a/crates/doc/src/eval.rs
+++ b/crates/doc/src/eval.rs
@@ -477,15 +477,23 @@ impl ModelState {
         if !f.shell_piece_order {
             crate::lineage::order_lumps(&mut self.bodies, &origin);
         }
+        // The bodies before the feature by name, in their order (names repeat only in damaged
+        // states): every lookup below is the first match of a linear search, without walking
+        // every earlier body for every body, after every feature.
+        let mut by_name: std::collections::HashMap<&str, Vec<&ModelBody>> = std::collections::HashMap::with_capacity(before.bodies.len());
+        for old in &before.bodies {
+            by_name.entry(old.name.as_str()).or_default().push(old);
+        }
         for b in &mut self.bodies {
+            let olds: &[&ModelBody] = by_name.get(b.name.as_str()).map(Vec::as_slice).unwrap_or_default();
             if !matches!(f.kind, FeatureKind::BodyTransfer { .. })
-                && let Some(old) = before.bodies.iter().find(|old| old.name == b.name && old.transferred)
+                && let Some(old) = olds.iter().find(|old| old.transferred)
             {
                 b.transferred = true;
                 b.component = old.component;
                 b.source_transform = old.source_transform;
             }
-            let kept = before.bodies.iter().find(|x| x.name == b.name && x.body.same(&b.body));
+            let kept = olds.iter().find(|x| x.body.same(&b.body));
             match kept {
                 Some(x) => {
                     b.key = x.key;
@@ -501,14 +509,14 @@ impl ModelState {
                     }
                     // Faces split on purpose stay split through later features (for export).
                     if b.body.split_lines().is_none()
-                        && let Some(lines) = before.bodies.iter().find(|x| x.name == b.name).and_then(|x| x.body.split_lines())
+                        && let Some(lines) = olds.first().and_then(|x| x.body.split_lines())
                     {
                         b.body = b.body.clone().with_split_lines(Some(lines.clone()));
                     }
                     // An imported look outlives the operations on the body.
                     if b.body.paint().is_none()
                         && b.body.color().is_none()
-                        && let Some(old) = before.bodies.iter().find(|x| x.name == b.name)
+                        && let Some(old) = olds.first()
                     {
                         b.imported = crate::appearance::ImportedLook::of(old);
                     }
@@ -1001,6 +1009,12 @@ impl Model {
         let mut restored = 0;
         let marker = doc.marker.unwrap_or(usize::MAX);
         let ctx = context_digest(doc, &vals);
+        // Each feature's component, for `Document::legacy_body_component` on every body after
+        // every feature without searching the timeline for each (the first feature with an id).
+        let mut feature_component: std::collections::HashMap<u64, u64> = std::collections::HashMap::with_capacity(doc.features.len());
+        for f in &doc.features {
+            feature_component.entry(f.id).or_insert(f.component);
+        }
         let watched = crate::progress::begin(doc.features.len());
         for (i, f) in doc.features.iter().enumerate() {
             let rolled_back = i >= marker;
@@ -1143,7 +1157,10 @@ impl Model {
                     next.stamp(&state, f, key, mats);
                     for b in &mut next.bodies {
                         if !b.transferred {
-                            b.component = doc.legacy_body_component(&b.name, b.feature);
+                            b.component = match doc.body_components.get(&b.name) {
+                                Some(c) => *c,
+                                None => feature_component.get(&b.feature).copied().unwrap_or(0),
+                            };
                         }
                     }
                     state = Arc::new(next);
diff --git a/crates/kernel/src/body.rs b/crates/kernel/src/body.rs
index a0e9710f..d9852844 100644
--- a/crates/kernel/src/body.rs
+++ b/crates/kernel/src/body.rs
@@ -467,6 +467,15 @@ fn span_of(solid: &Solid) -> f64 {
     if lo.x.is_finite() { (hi - lo).len() } else { 1.0 }
 }
 
+/// Equal shared values: the same allocation (a clone of the body), else equal contents.
+fn same_shared<T: PartialEq>(a: &Option<std::sync::Arc<T>>, b: &Option<std::sync::Arc<T>>) -> bool {
+    match (a, b) {
+        (Some(a), Some(b)) => std::sync::Arc::ptr_eq(a, b) || a == b,
+        (None, None) => true,
+        _ => false,
+    }
+}
+
 impl Body {
     /// The very same body (shared data), not just an equal-looking one. Its history (how an
     /// operation made it) is not part of it: an operation that leaves a body as it is (a cut by
@@ -479,9 +488,9 @@ impl Body {
                 _ => false,
             }
             && self.color == other.color
-            && self.paint == other.paint
-            && self.splits == other.splits
-            && self.face_sources == other.face_sources
+            && same_shared(&self.paint, &other.paint)
+            && same_shared(&self.splits, &other.splits)
+            && same_shared(&self.face_sources, &other.face_sources)
             && self.regularization_protected == other.regularization_protected
     }