Reconstruct constant-section meshes as parametric solids

crates/doc/src/assembly.rs

@@ -329,6 +329,7 @@ impl FeatureKind {
             | FeatureKind::Thicken { .. }
             | FeatureKind::Import { .. }
             | FeatureKind::MeshImport { .. }
+            | FeatureKind::MeshConvert { .. }
             | FeatureKind::BodyTransfer { .. } => {}
             FeatureKind::Patch { edges, .. } | FeatureKind::SurfaceExtend { edges, .. } => edges.iter_mut().for_each(pt),
             FeatureKind::SurfaceTrim { plane, tool, keep, .. } => {

crates/doc/src/clipboard.rs

@@ -356,9 +356,11 @@ impl crate::Feature {
                     mapped_name(n, bodies);
                 }
             }
-            K::Split { body, .. } | K::SheetConvert { body, .. } | K::SurfaceExtend { body, .. } | K::SurfaceTrim { body, .. } => {
-                mapped_name(body, bodies)
-            }
+            K::Split { body, .. }
+            | K::SheetConvert { body, .. }
+            | K::SurfaceExtend { body, .. }
+            | K::SurfaceTrim { body, .. }
+            | K::MeshConvert { body, .. } => mapped_name(body, bodies),
             _ => {}
         }
         match &mut self.kind {

crates/doc/src/document.rs

@@ -883,8 +883,12 @@ pub enum FeatureKind {
         #[serde(default, skip_serializing_if = "Vec::is_empty")]
         components: Vec<solvecraft_kernel::StepNode>,
     },
-    /// A non-parametric base feature: mesh bodies imported from a 3MF or STL file (kept in the
-    /// design). Mesh bodies render, measure, move and export; solid features cannot use them.
+    /// Rebuild an upstream constant-section mesh with analytic planar/cylindrical faces.
+    MeshConvert {
+        body: String,
+        tolerance: String,
+    },
+    /// Mesh bodies imported from a 3MF or STL file, embedded in the design.
     MeshImport {
         /// Source file name (display only).
         file: String,
@@ -1162,6 +1166,7 @@ impl FeatureKind {
             | K::Move { .. }
             | K::Import { .. }
             | K::MeshImport { .. }
+            | K::MeshConvert { .. }
             | K::BodyTransfer { .. } => Vec::new(),
         }
     }
@@ -1247,6 +1252,7 @@ impl FeatureKind {
             FeatureKind::SurfaceExtend { .. } => "ExtendFeature",
             FeatureKind::Import { .. } => "BaseFeature",
             FeatureKind::MeshImport { .. } => "MeshFeature",
+            FeatureKind::MeshConvert { .. } => "MeshConvertFeature",
         }
     }
     /// Default name prefix (`Extrude` → `Extrude1`).
@@ -1312,6 +1318,7 @@ impl FeatureKind {
             FeatureKind::SurfaceExtend { .. } => "Extend",
             FeatureKind::Import { .. } => "Import",
             FeatureKind::MeshImport { .. } => "Mesh",
+            FeatureKind::MeshConvert { .. } => "ConvertMesh",
         }
     }
     /// Every expression the feature uses.
@@ -1520,6 +1527,7 @@ impl FeatureKind {
             FeatureKind::ReplaceFace { target, .. } => plane_exprs(target, &mut v),
             FeatureKind::Align { .. } | FeatureKind::Remove { .. } | FeatureKind::BoundaryFill { .. } | FeatureKind::DeleteFace { .. } => {}
             FeatureKind::Stitch { tolerance, .. } => v.push(tolerance),
+            FeatureKind::MeshConvert { tolerance, .. } => v.push(tolerance),
             FeatureKind::Thicken { thickness, .. } => v.push(thickness),
             FeatureKind::SurfaceTrim { plane, .. } => plane_exprs(plane, &mut v),
             FeatureKind::SurfaceExtend { distance, .. } => v.push(distance),

crates/doc/src/eval.rs

@@ -3299,6 +3299,20 @@ fn eval_feature(doc: &Document, vals: &BTreeMap<String, Value>, f: &Feature, st:
             }
             Ok(())
         }
+        FeatureKind::MeshConvert { body, tolerance } => {
+            let tolerance = val(vals, tolerance, Kind::Length)?;
+            let index = st.bodies.iter().position(|b| &b.name == body).ok_or_else(|| DocError::Unknown(format!("body `{body}`")))?;
+            let source = st.bodies.get(index).ok_or_else(|| DocError::Unknown(format!("body `{body}`")))?;
+            if doc.model_body_component(source) != f.component {
+                return Err(DocError::Invalid("activate the mesh body's component before converting it".into()));
+            }
+            let converted = kernel::convert_prismatic_mesh(&source.body, tolerance)?;
+            let converted = converted.with_color(source.body.color());
+            let result = ModelBody::new(source.name.clone(), converted, f.id);
+            let target = st.bodies.get_mut(index).ok_or_else(|| DocError::Unknown(format!("body `{body}`")))?;
+            *target = result;
+            Ok(())
+        }
         FeatureKind::MeshImport { meshes, .. } => {
             for (k, (name, b)) in mesh_bodies(meshes)?.into_iter().enumerate() {
                 let name = copy_body_name(st, f, k, &name);

crates/doc/src/params.rs

@@ -259,6 +259,7 @@ impl FeatureKind {
             }
             FeatureKind::ReplaceFace { target, .. } => plane_inputs_mut(target, &mut v),
             FeatureKind::Stitch { tolerance, .. } => v.push(("Tolerance", tolerance, L)),
+            FeatureKind::MeshConvert { tolerance, .. } => v.push(("Tolerance", tolerance, L)),
             FeatureKind::Thicken { thickness, .. } => v.push(("Thickness", thickness, L)),
             FeatureKind::SurfaceTrim { plane, .. } => plane_inputs_mut(plane, &mut v),
             FeatureKind::SurfaceExtend { distance, .. } => v.push(("Distance", distance, L)),