docs: node relaxation in features, MCP guide, control protocol, literature and the meshing skill (#398)

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01UhhZMBTviDQxZvwnyP89fo

crates/engine/src/catalogue.rs

@@ -354,6 +354,14 @@ pub static CATALOGUE: &[Capability] = &[
     soon("mesh.smooth", "Smooth", Mesh, "Improve", "M6", "Smooth node positions, keeping every element valid"),
     soon("mesh.untangle", "Untangle", Mesh, "Improve", "M6", "Repair inverted elements"),
     soon("mesh.layers", "Layers", Mesh, "Improve", "M6", "Boundary padding and layers through thin walls"),
+    ready_more(
+        "mesh.node.relax",
+        "Relax Nodes",
+        Mesh,
+        "Improve",
+        "Relax the nodes inside a sphere to fix spikes and slivers; surface nodes slide on the geometry; kept as a field to apply again after a remesh",
+        &["mesh.node.relax.apply"],
+    ),
     ready_more("mesh.node.add", "Node", Mesh, "Edit", "Add a node", &["mesh.node.remove"]),
     ready_more("mesh.element.add", "Element", Mesh, "Edit", "Add an element on existing nodes", &["mesh.element.remove", "mesh.clear"]),
     ready("mesh.mirror", "Mirror Mesh", Mesh, "Edit", "Mirror a body's mesh across a plane, joined on the plane (mesh half a symmetric part)"),
@@ -365,14 +373,6 @@ pub static CATALOGUE: &[Capability] = &[
         "Merge coincident nodes, keeping sets, loads and boundary conditions on the survivors; check for duplicates and cracks, renumber",
         &["mesh.check.duplicates", "mesh.renumber"],
     ),
-    ready_more(
-        "mesh.node.relax",
-        "Relax Nodes",
-        Mesh,
-        "Improve",
-        "Relax the nodes inside a sphere to fix spikes and slivers; surface nodes slide on the geometry; kept as a field to apply again after a remesh",
-        &["mesh.node.relax.apply"],
-    ),
     soon("mesh.region.remesh", "Remesh Region", Mesh, "Edit", "M6", "Remesh a region in place; split and collapse elements"),
     soon("mesh.import.orphan", "Orphan Mesh", Mesh, "Edit", "M6", "Import a mesh without geometry"),
     ready("mesh.quality", "Quality", Mesh, "Verify", "Quality metrics and the certified validity check, failing elements listed"),

crates/engine/src/cmd/forms.rs

@@ -1891,6 +1891,7 @@ mod tests {
         "has a result",
         "no crash report",
         "FIELDCRAFT_CRASH_TEST",
+        "no relaxation field",
     ];
 
     /// Fill top-level required names (a fresh one) and references (the first existing item).

crates/engine/src/cmd/relax.rs

@@ -374,7 +374,7 @@ pub(crate) fn weights(model: &Model, p: &Value) -> Result<(BTreeMap<u32, f64>, O
         nodes.extend(el.nodes.iter().copied());
     }
     if listed == 0 {
-        return Err(EngineError::Params("say which nodes to relax: `center` and `radius`, `around_element`, `nodes`, `elements` or `set`".into()));
+        return Err(EngineError::Params("say which nodes to relax: give one of `center` and `radius`, `around_element`, `nodes`, `elements` or `set`".into()));
     }
     if let Some(only) = &only {
         nodes.retain(|n| only.contains(n));

docs/control-protocol.md

@@ -58,7 +58,7 @@ commands (files, undo, `model.info`) leave the ribbon where it is.
 | `ui.settings` | — | opens Help › Settings… (answered with `ui.prompt`); replies with the privacy state as `ui.inspect`'s `privacy` gives it: `available` (this run may share usage), `usage_sharing` (`null` until asked), `usage_automation`, `recording`, `queued` |
 | `ui.item` | `kind` (`body`, `surface`, or a definition kind as `ui.select` takes it, `datum`, `partition`), `name`, `action`: `edit`, `rename`, `suppress`/`unsuppress` (a datum or partition), `hide`, `show`, `isolate`, `show_all`, `delete`, or `activate`/`deactivate` with `step` | an item menu's entry, as a right click on the item and a click on the entry: runs the same command (`rename` opens the `model.rename` form filled in; `delete` opens the delete prompt, answered with `ui.prompt`) |
 | `ui.dialog` | `params?` (JSON object, fills the form), `use_selection?`, `run?`, `submit?`, `cancel?` | drives the open command form, in that order; `use_selection` is the form's Target row (see [Selection](#selection)); `run` returns the command's result and closes the form on success; `submit` is the form's OK button: a mesher that would replace a body's mesh first asks (`prompt` `replace_mesh`, with the question and what else goes: sets listing the old labels, solved results), and meshers run in the background (`busy`); a form opened by another form's **Create …** button (a reference field with nothing to pick) goes back to that form on `run` (with the new item picked) or `cancel` |
-| `ui.click` | `x`, `y` (screen points), `button?`: `left`/`right`/`middle`, `shift?`, `ctrl?`, `alt?`, `double?` | real pointer input; in the viewport a click selects what is under it (Shift adds, Ctrl/Cmd adds or removes, a click on nothing clears the selection), and a click on a results plot also probes the nearest node of the face under it (`solve.probe`; `ui.inspect` shows the values) |
+| `ui.click` | `x`, `y` (screen points), `button?`: `left`/`right`/`middle`, `shift?`, `ctrl?`, `alt?`, `double?` | real pointer input; in the viewport a click selects what is under it (Shift adds, Ctrl/Cmd adds or removes, a click on nothing clears the selection), and a click on a results plot also probes the nearest node of the face under it (`solve.probe`; `ui.inspect` shows the values); with the Relax Nodes form open (`mesh.node.relax`) a click on the mesh places its sphere of influence instead (Alt + wheel sizes it) |
 | `ui.move` | `x`, `y` | |
 | `ui.drag` | `x0`, `y0`, `x1`, `y1`, `button?`, `shift?`, `ctrl?`, `steps?` (1–200) | press, move, release: in the viewport the drag does what the navigation preset (`ui.set {nav_preset}`) binds; by default a left drag orbits about the model point under the press, or the centre of what is drawn from empty space (with box selection on, it selects the visible nodes, element faces or elements in the box; Ctrl + left from empty space still orbits), a right or middle drag (or Shift + left) pans |
 | `ui.scroll` | `x`, `y`, `delta?` (wheel lines, −100–100; positive zooms in) | zooms toward the model point under `x`, `y` (the point at the target's depth over empty space), by the same factor per line in orthographic and perspective views; `ui.set {reverse_zoom}` turns it the other way |

docs/features.md

@@ -46,11 +46,11 @@ the control channel and AI agents over MCP (docs/mcp.md) run the same commands.
 | Improve | Smooth — Smooth node positions, keeping every element valid | coming soon (M6) |  |
 | Improve | Untangle — Repair inverted elements | coming soon (M6) |  |
 | Improve | Layers — Boundary padding and layers through thin walls | coming soon (M6) |  |
+| Improve | Relax Nodes — Relax the nodes inside a sphere to fix spikes and slivers; surface nodes slide on the geometry; kept as a field to apply again after a remesh | ready | `mesh.node.relax`, `mesh.node.relax.apply` |
 | Edit | Node — Add a node | ready | `mesh.node.add`, `mesh.node.remove` |
 | Edit | Element — Add an element on existing nodes | ready | `mesh.element.add`, `mesh.element.remove`, `mesh.clear` |
 | Edit | Mirror Mesh — Mirror a body's mesh across a plane, joined on the plane (mesh half a symmetric part) | ready | `mesh.mirror` |
 | Edit | Merge Nodes — Merge coincident nodes, keeping sets, loads and boundary conditions on the survivors; check for duplicates and cracks, renumber | ready | `mesh.node.merge`, `mesh.check.duplicates`, `mesh.renumber` |
-| Improve | Relax Nodes — Relax the nodes inside a sphere to fix spikes and slivers; surface nodes slide on the geometry; kept as a field to apply again after a remesh | ready | `mesh.node.relax`, `mesh.node.relax.apply` |
 | Edit | Remesh Region — Remesh a region in place; split and collapse elements | coming soon (M6) |  |
 | Edit | Orphan Mesh — Import a mesh without geometry | coming soon (M6) |  |
 | Verify | Quality — Quality metrics and the certified validity check, failing elements listed | ready | `mesh.quality` |