Booleans stay in their component: a join, cut or intersect without explicit targets changes only its own component's bodies (and what it made), auto join/cut looks only at the active component; any feature takes participants: [bodies] to reach other components ("*" = every body); file format 5 gives older features in designs with components participants ["*"] so they keep their shape

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01AS5Tn3xieewUSg3uxrMVdL

crates/doc/src/document.rs

@@ -1045,6 +1045,10 @@ pub struct Feature {
     /// Persistent names of the faces at the feature's face points (`FeatureKind::face_points`).
     #[serde(default, skip_serializing_if = "Vec::is_empty")]
     pub face_names: Vec<String>,
+    /// Bodies a join/cut/intersect may change (any component); empty = the feature's own
+    /// component's bodies.
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub participants: Vec<String>,
     #[serde(flatten)]
     pub kind: FeatureKind,
 }
@@ -1324,6 +1328,7 @@ impl Document {
             edge_refs: Vec::new(),
             edge_names: Vec::new(),
             face_names: Vec::new(),
+            participants: Vec::new(),
             kind,
         };
         match self.marker {

crates/doc/src/eval.rs

@@ -25,11 +25,13 @@ pub struct ModelBody {
     key: u64,
     /// Persistent face names (worked out on first use).
     pub(crate) names: crate::naming::NameCell,
+    /// The component the body belongs to (set after each feature).
+    pub component: u64,
 }
 
 impl ModelBody {
     pub fn new(name: String, body: Body, feature: u64) -> Self {
-        ModelBody { name, body, feature, mesh: OnceLock::new(), key: 0, names: Default::default() }
+        ModelBody { name, body, feature, mesh: OnceLock::new(), key: 0, names: Default::default(), component: 0 }
     }
     /// Display mesh (chord tolerance 1/1000 of the body size), computed once.
     pub fn mesh(&self) -> Arc<Mesh> {
@@ -564,6 +566,9 @@ impl Model {
                         _ => Vec::new(),
                     };
                     next.stamp(&state, f, key, mats);
+                    for b in &mut next.bodies {
+                        b.component = doc.body_component(&b.name, b.feature);
+                    }
                     state = Arc::new(next);
                     None
                 }
@@ -652,8 +657,14 @@ fn new_name(state: &mut ModelState, f: &Feature, k: usize) -> String {
 
 /// Add tool bodies to the model according to the operation.
 fn apply_op(state: &mut ModelState, f: &Feature, tools: Vec<Body>, op: Operation, targets: &[String]) -> Result<()> {
-    let target_idx: Vec<usize> = if targets.is_empty() {
+    // Participants: the feature's own targets, else its explicit participants, else the bodies
+    // of its component (and what it made itself): other components are left alone.
+    let targets: &[String] = if targets.is_empty() { &f.participants } else { targets };
+    let all = targets.len() == 1 && targets.first().is_some_and(|t| t == "*");
+    let target_idx: Vec<usize> = if all {
         (0..state.bodies.len()).collect()
+    } else if targets.is_empty() {
+        (0..state.bodies.len()).filter(|i| state.bodies.get(*i).is_some_and(|b| b.component == f.component || b.feature == f.id)).collect()
     } else {
         let mut v = Vec::new();
         for t in targets {

crates/doc/src/format.rs

@@ -13,6 +13,9 @@
 //! - 3: appearances per body, face and component with names and opacity
 //!   (`"appearances": {"bodies": {name: {name, color, opacity}}, "faces": […], "components": {…}}`);
 //!   before, `"appearances"` mapped body names to bare `[r, g, b]` colours.
+//! - 5: joins, cuts and intersects change only their own component's bodies unless bodies are
+//!   named as `participants`; older features in designs with components get `participants:
+//!   ["*"]` (every body), which is what they did, so those designs keep their shape.
 //! - 4: joint origins mate by default (B's z against A's, as Fusion does); `flip` now means
 //!   "don't mate". Older joints keep their placement: their `flip` is inverted.
 
@@ -21,7 +24,7 @@ use serde_json::Value;
 use crate::{DocError, Document, Result};
 
 /// The format this build writes.
-pub const FORMAT: u32 = 4;
+pub const FORMAT: u32 = 5;
 
 pub fn format_string(n: u32) -> String {
     format!("solvecraft/{n}")
@@ -34,7 +37,26 @@ pub fn version_of(s: &str) -> Option<u32> {
 
 /// JSON-level upgrades: entry `i` turns format `i + 1` into `i + 2`.
 type JsonStep = fn(&mut Value) -> Result<()>;
-const JSON_STEPS: [JsonStep; 3] = [|_| Ok(()), v2_to_v3, v3_to_v4];
+const JSON_STEPS: [JsonStep; 4] = [|_| Ok(()), v2_to_v3, v3_to_v4, v4_to_v5];
+
+/// Features in designs with components keep reaching every body.
+fn v4_to_v5(v: &mut Value) -> Result<()> {
+    let has_components = v.get("components").and_then(Value::as_array).is_some_and(|c| !c.is_empty());
+    if !has_components {
+        return Ok(());
+    }
+    if let Some(Value::Array(fs)) = v.get_mut("features") {
+        for f in fs.iter_mut() {
+            if let Some(o) = f.as_object_mut()
+                && o.get("type").and_then(Value::as_str) != Some("sketch")
+                && o.get("participants").is_none()
+            {
+                o.insert("participants".into(), serde_json::json!(["*"]));
+            }
+        }
+    }
+    Ok(())
+}
 
 /// Joints placed with the old convention (aligned unless flipped) keep their placement.
 fn v3_to_v4(v: &mut Value) -> Result<()> {

crates/engine/src/cmd/features.rs

@@ -139,7 +139,14 @@ pub fn auto_operation(s: &Session, p: &Value) -> Option<&'static str> {
     if st.bodies.is_empty() || !d.is_finite() {
         return Some("new");
     }
-    let inside = |q: Vec3| st.bodies.iter().any(|b| b.mesh().contains(q));
+    // Only the active component's bodies take part (or the ones named as participants).
+    let parts = string_list(p, "participants");
+    let inside = |q: Vec3| {
+        st.bodies
+            .iter()
+            .filter(|b| if parts.is_empty() { s.doc.body_component(&b.name, b.feature) == s.active_component } else { parts.contains(&b.name) })
+            .any(|b| b.mesh().contains(q))
+    };
     let eps = (d.abs() * 1e-3).max(1e-3);
     let sign = if d < 0.0 { -1.0 } else { 1.0 };
     if symmetric {
@@ -262,8 +269,13 @@ pub(super) fn add_feature(s: &mut Session, p: &Value, kind: FeatureKind) -> Resu
         let pts = kind.face_points();
         if pts.is_empty() { Vec::new() } else { solvecraft_doc::naming::face_names_at(&s.model.state(), &pts) }
     };
+    let participants = string_list(p, "participants");
+    if participants.len() > 10_000 || participants.iter().any(|b| b != "*" && s.model.state().body(b).is_none()) {
+        return Err(EngineError::Other("`participants` must list existing bodies".into()));
+    }
     let id = s.doc_mut().add_feature(kind, name)?;
     if let Some(f) = s.doc_mut().feature_mut(id) {
+        f.participants = participants;
         f.edge_refs = refs;
         f.edge_names = names;
         f.face_names = face_names;

crates/engine/src/tests.rs

@@ -1387,6 +1387,8 @@ fn tapped_and_clearance_holes() {
     assert!(rel(v2 - volume(&mut s), PI * 2.15 * 2.15 * 10.0) < 1e-3);
     assert!(s.execute("FusionHoleCommand", &json!({"position": [20, 25, 10], "clearance": "M7"})).is_err());
     assert!(s.execute("FusionHoleCommand", &json!({"position": [20, 25, 10]})).is_err());
+}
+
 /// In an inch design, a bare length typed into a feature means inches (stored with the unit);
 /// lengths with units and angles are left alone.
 #[test]
@@ -1427,3 +1429,30 @@ fn press_pull_on_curved_faces() {
     let v1 = volume(&mut s);
     assert!(rel(v1 - v0, PI * (25.0 - 16.0) * 20.0) < 1e-3, "{v0} {v1}");
 }
+
+/// A cut in one component leaves other components' bodies alone unless they are named as
+/// participants; auto join/cut looks at the active component only.
+#[test]
+fn booleans_stay_in_their_component() {
+    let mut s = Session::default();
+    for (name, x) in [("A", 0), ("B", 20)] {
+        run(&mut s, "component.activate", json!({"component": "root"}));
+        run(&mut s, "FusionCreateNewComponentCommand", json!({"name": name}));
+        run(&mut s, "PrimitiveBox", json!({"length": 20, "width": 10, "height": 10, "corner": [x, 0, 0], "body_name": format!("{name}Box")}));
+    }
+    // A's box spans x 0…20, B's x 20…40 (in their own frames, both occurrences in place).
+    run(&mut s, "component.activate", json!({"component": "A"}));
+    run(&mut s, "SketchCreate", json!({"plane": "XY", "name": "Slot"}));
+    run(&mut s, "ShapeRectangleTwoPoint", json!({"p0": [8, 2], "p1": [28, 8]}));
+    run(&mut s, "SketchStop", json!({}));
+    let vol = |s: &mut Session, b: &str| run(s, "MeasureCommand", json!({"bodies": [b]}))["total"]["volume_mm3"].as_f64().unwrap_or(0.0);
+    assert_eq!(auto_operation(&s, &json!({"sketch": "Slot", "distance": 10})), Some("cut"));
+    run(&mut s, "Extrude", json!({"sketch": "Slot", "distance": 10, "operation": "cut", "name": "Cut"}));
+    assert!((vol(&mut s, "ABox") - (2000.0 - 12.0 * 6.0 * 10.0)).abs() < 1e-6, "{}", vol(&mut s, "ABox"));
+    assert!((vol(&mut s, "BBox") - 2000.0).abs() < 1e-6, "B untouched: {}", vol(&mut s, "BBox"));
+    // Named as a participant, B is cut too.
+    run(&mut s, "UndoCommand", json!({}));
+    run(&mut s, "Extrude", json!({"sketch": "Slot", "distance": 10, "operation": "cut", "participants": ["ABox", "BBox"]}));
+    assert!((vol(&mut s, "BBox") - (2000.0 - 8.0 * 6.0 * 10.0)).abs() < 1e-6, "{}", vol(&mut s, "BBox"));
+    assert!(s.execute("Extrude", &json!({"sketch": "Slot", "distance": 1, "operation": "cut", "participants": ["Nope"]})).is_err());
+}