mesh: geometry.features, mesh.plan and mesh.plan.apply from the feature graph (#402)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UhhZMBTviDQxZvwnyP89fo

crates/engine/src/cmd/forms.rs

@@ -1599,6 +1599,15 @@ pub const PARTITION: &[Field] = &[
     references("bodies", "Bodies", C::Body).help("The bodies to divide; every body the plane cuts when empty.").hint("every body the plane divides"),
 ];
 pub const PARTITION_DELETE: &[Field] = existing!("Partition", C::Partition);
+pub const MESH_PLAN: &[Field] = &[
+    reference("body", "Body", C::Body).help("The body of the design to plan (as opened, not a partition cell).").req(),
+    text("name", "Name").help("The name the plan is saved under.").hint("Plan-<body>"),
+    positive("size", "Element size", D::Millimetre).help("The largest element size; thin walls make it smaller.").hint("1/25 of the diagonal"),
+    int("layers", "Layers through walls", 1, 10).help("Elements through the thinnest wall the features give (a shell, a plate).").hint("2"),
+    int("max_elements", "Most elements", 1, 5_000_000).help("The size grows past the walls' when more elements would be needed.").hint("300000"),
+];
+pub const MESH_PLAN_APPLY: &[Field] = &[text("plan", "Plan").help("The name of a saved mesh plan (mesh.plan).").req()];
+pub const FEATURES: &[Field] = &[reference("body", "Body", C::Body).help("Only this body's features.").hint("every body")];
 pub const TESSELLATE: &[Field] = &[reference("body", "Body", C::Body).help("The body to tessellate.").req(), TOLERANCE];
 pub const IMPORT_MESH: &[Field] = &[path("path", "3MF file", false).help("A 3MF surface mesh with named faces.").req()];
 pub const FILE_OPEN: &[Field] = &[path("path", "Model", false).help("The FieldCraft model file to open.").req()];

crates/engine/src/cmd/geometry.rs

@@ -33,6 +33,16 @@ pub const BODIES: CommandSpec = CommandSpec {
     run: bodies,
 };
 
+pub const FEATURES: CommandSpec = CommandSpec {
+    id: "geometry.features",
+    label: "Feature Graph",
+    params: r#"{"body"?: "Base" (default: every body)} — the features of the SolidCraft timeline that built each body of the open design, in order (read-only): each feature's `id` (`F<id>` in persistent names), `name`, `type` (extrude, box, cylinder, hole, shell, fillet, combine, pattern, mirror, split, …), `operation` (new_body, join, cut, intersect), `values` (its numeric inputs evaluated: mm, radians, counts), `placement` (a primitive's corner, base or centre), `direction` (an extrude's along the sketch normal, a cylinder's axis, a hole's drilling direction), `two_sided`, `sketch` (plane origin, axes and normal, and the profiles used: lines, arcs and circles in sketch coordinates, holes, curve ids), `transforms` (pattern and mirror copies, 4×4 row-major), `targets` and `tools`, the stored `definition`, the persistent `faces` and `edges` of the body it made, and `error` when it failed to rebuild. A partition cell is described by the body it was cut from"#,
+    form: Some(super::forms::FEATURES),
+    kind: CommandKind::Model,
+    requires: &[Requirement::Design],
+    run: features,
+};
+
 pub const CENTRE: CommandSpec = CommandSpec {
     id: "geometry.centre",
     label: "Centre of Selection",
@@ -170,6 +180,16 @@ fn bodies(s: &mut Session, _: &Value) -> Result<Value> {
     Ok(Value::Array(out))
 }
 
+fn features(s: &mut Session, p: &Value) -> Result<Value> {
+    let body = match p.get("body") {
+        None | Some(Value::Null) => None,
+        Some(v) => Some(v.as_str().ok_or_else(|| EngineError::param("body", ProblemKind::NotAName))?),
+    };
+    let design = s.design.as_deref().ok_or_else(|| EngineError::Params("open a design first".into()))?;
+    let graph = design.features(body)?;
+    Ok(json!({"bodies": graph}))
+}
+
 /// Most geometry items and nodes `geometry.centre` takes.
 const MAX_CENTRE_ITEMS: usize = 10_000;
 

crates/engine/src/cmd/mod.rs

@@ -23,6 +23,7 @@ mod mirror;
 mod model;
 pub(crate) mod nodes;
 pub(crate) mod octree;
+pub(crate) mod plan;
 mod project;
 pub(crate) mod relax;
 pub mod replace;
@@ -47,6 +48,7 @@ pub static ALL: &[CommandSpec] = &[
     model::INFO,
     geometry::OPEN,
     geometry::BODIES,
+    geometry::FEATURES,
     geometry::CENTRE,
     geometry::TESSELLATE,
     geometry::IMPORT_MESH,
@@ -83,6 +85,8 @@ pub static ALL: &[CommandSpec] = &[
     hex::HEX_BLOCKS,
     project::HEX_PROJECT,
     cells::CELLS,
+    plan::PLAN,
+    plan::APPLY,
     seeds::SEED_EDGE,
     seeds::SEED_CLEAR,
     seeds::SEED_LIST,

crates/engine/src/cmd/relax.rs

@@ -52,6 +52,7 @@ const REMESH: &[&str] = &[
     "mesh.hex.sweep",
     "mesh.hex.mapped",
     "mesh.hex.blocks",
+    "mesh.plan.apply",
     "mesh.hex.octree",
     "mesh.cells",
     "mesh.block",

crates/engine/src/cmd/replace.rs

@@ -130,6 +130,7 @@ pub static MESHERS: &[(&str, Targets)] = &[
     ("mesh.hex.blocks", listed_or_all),
     ("mesh.hex.project", body_or_all),
     ("mesh.cells", listed_or_all),
+    ("mesh.plan.apply", super::plan::plan_bodies),
     ("mesh.planar", super::mesh::planar_body),
     ("mesh.mirror", super::mirror::image_names),
 ];
@@ -173,7 +174,7 @@ fn made_kind(command: &str, params: &Value) -> Option<ElementKind> {
             Some(if params.get("order").and_then(Value::as_str) == Some("quadratic") { ElementKind::Tet10 } else { ElementKind::Tet4 })
         }
         "mesh.hex.project" => Some(ElementKind::Hex8),
-        "mesh.hex.generate" | "mesh.hex.sweep" | "mesh.hex.mapped" | "mesh.hex.blocks" => {
+        "mesh.hex.generate" | "mesh.hex.sweep" | "mesh.hex.mapped" | "mesh.hex.blocks" | "mesh.plan.apply" => {
             Some(if params.get("order").and_then(Value::as_i64) == Some(2) { ElementKind::Hex20 } else { ElementKind::Hex8 })
         }
         _ => None,
@@ -313,6 +314,13 @@ mod tests {
             ("mesh.hex.blocks", vec![tet_other.clone()], json!({"bodies": ["Box.1"], "size": 2.5}), "Box.1", "Box.2"),
             ("mesh.hex.project", vec![tet_other.clone()], json!({"body": "Box.1", "size": 2.5, "merge": 0}), "Box.1", "Box.2"),
             ("mesh.cells", vec![tet_other.clone()], json!({"bodies": ["Box.1"], "size": 2.5, "default": "hex"}), "Box.1", "Box.2"),
+            (
+                "mesh.plan.apply",
+                vec![tet_other.clone(), json!({"command": "mesh.plan", "params": {"body": "Box.1", "size": 2.5}})],
+                json!({"plan": "Plan-Box_1"}),
+                "Box.1",
+                "Box.2",
+            ),
             ("mesh.planar", vec![tet_other.clone()], json!({"polygon": square, "size": 2.5, "name": "Box.1"}), "Box.1", "Box.2"),
             // The image's tets (meshed before) are replaced by the mirrored hexahedra.
             (