solid.cylinder, box, sphere, torus and coil place by expressions: base, corner and center take numbers or length expressions per coordinate ("basin_width/2", "10 mm") and follow parameter changes, renames and component frames; before, a point that was not three plain numbers (or an unreadable axis) was silently replaced by the origin (or Z). The features now store the point as expressions (plain numbers still saved as numbers, so existing designs read and write the same) and evaluate it on every recompute; an unreadable or out-of-range point or axis is refused with an error. Tests: primitive points take expressions, follow parameters, renames and a moved component, and bad points are refused

crates/doc/src/params.rs

@@ -276,6 +276,32 @@ impl FeatureKind {
         v
     }
 
+    /// A primitive's placement point (length expressions). Its coordinates are not inputs:
+    /// they get no parameter names and keep bare numbers in mm whatever the design's units, as
+    /// every other position does; renames and users still find them.
+    pub fn point_expr_mut(&mut self) -> Option<&mut crate::PointExpr> {
+        match self {
+            FeatureKind::Box { corner: p, .. }
+            | FeatureKind::Cylinder { base: p, .. }
+            | FeatureKind::Sphere { center: p, .. }
+            | FeatureKind::Torus { center: p, .. }
+            | FeatureKind::Coil { base: p, .. } => Some(p),
+            _ => None,
+        }
+    }
+
+    /// Read-only view of [`FeatureKind::point_expr_mut`].
+    pub fn point_expr(&self) -> Option<&crate::PointExpr> {
+        match self {
+            FeatureKind::Box { corner: p, .. }
+            | FeatureKind::Cylinder { base: p, .. }
+            | FeatureKind::Sphere { center: p, .. }
+            | FeatureKind::Torus { center: p, .. }
+            | FeatureKind::Coil { base: p, .. } => Some(p),
+            _ => None,
+        }
+    }
+
     /// Read-only view of [`FeatureKind::inputs_mut`]: (label, expression, kind).
     pub fn inputs(&self) -> Vec<(&'static str, String, Kind)> {
         // Imports have no inputs (and their STEP text is large: don't clone it).
@@ -655,6 +681,9 @@ impl Document {
                     }
                 }
             }
+            if f.kind.point_expr().is_some_and(|p| p.iter().any(|e| expr::references(e).iter().any(|r| r == name))) {
+                out.push(ParamUser::Feature { feature: f.id, name: f.name.clone(), input: "Position".into() });
+            }
             if let FeatureKind::Sketch { sketch, .. } = &f.kind {
                 for c in &sketch.constraints {
                     if c.param.as_deref() == Some(name) {
@@ -718,6 +747,13 @@ impl Document {
                     *x = new.to_string();
                 }
             }
+            for e in f.kind.point_expr_mut().into_iter().flatten() {
+                let r = expr::rename_reference(e, old, new);
+                if r != *e {
+                    *e = r;
+                    n += 1;
+                }
+            }
             for (_, e, _) in f.kind.inputs_mut() {
                 let r = expr::rename_reference(e, old, new);
                 if r != *e {