M0: workspace, geometry foundation, sketch constraint solver, kernel boundary

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/kernel/src/measure.rs

@@ -0,0 +1,42 @@
+use serde::Serialize;
+use solvecraft_geom::{Aabb3, Vec3};
+
+use crate::Result;
+use crate::body::Body;
+use crate::topo::{TopoCounts, merged_topology};
+
+/// Measured properties of a body.
+#[derive(Clone, Debug, Serialize)]
+pub struct BodyMeasure {
+    pub volume: f64,
+    pub area: f64,
+    pub centroid: Vec3,
+    pub bbox: Aabb3,
+    /// Raw kernel topology counts (closed curves and surfaces may be split in pieces).
+    pub faces: usize,
+    pub edges: usize,
+    pub vertices: usize,
+    pub shells: usize,
+    /// Counts after merging split pieces of the same analytic surface/curve (comparable with
+    /// systems that use periodic faces and edges).
+    pub merged: TopoCounts,
+}
+
+/// Measure a body from a fine tessellation (chord tolerance 5e-5 of the body size). Curved
+/// faces are slightly under-estimated (relative error typically below 2e-4).
+pub fn measure(b: &Body) -> Result<BodyMeasure> {
+    let size = b.size();
+    let m2 = b.tessellate((size * 5e-5).max(1e-4))?;
+    let a2 = m2.measure();
+    Ok(BodyMeasure {
+        volume: a2.volume,
+        area: a2.area,
+        centroid: a2.centroid,
+        bbox: m2.bounds(),
+        faces: b.face_count(),
+        edges: b.edge_count(),
+        vertices: b.vertex_count(),
+        shells: b.shell_count(),
+        merged: merged_topology(b, &m2)?,
+    })
+}