Sheet metal: a thousand cut-outs fit the flat budget, ten times faster (#732) (#964)

- A new cut was clipped against the panel with every one of its cut-outs, so
  each hole of a perforation cost the square of all the holes before it and the
  second cut of 500 ran out of the flat budget. A tool is now clipped against
  only the cut-outs whose boxes meet its own (the same result).
- The planar booleans' point-in-loop test now skips loops whose box is clear of
  the point, before the costly on-the-loop test; with a thousand holes that test
  was most of the time.

The 1000-hole panel now takes about 15 s instead of failing.

Co-authored-by: jonaswre <[email protected]>
Co-authored-by: Claude Opus 5.5 <[email protected]>

crates/doc/src/eval_more.rs

@@ -968,9 +968,13 @@ fn sheet_prism_cut(
                 }
                 modeled = true;
             } else if z1 > z0 {
+                // Each tool meets only the panel's cut-outs near it: arranging every one of a
+                // perforation's holes against every new hole would grow with their square (#732).
+                let near = sheet::NearHoles::new(&panel)?;
                 for flat in mapped {
+                    let local = near.around(&flat)?;
                     let clipped =
-                        sheet::material_boolean(std::slice::from_ref(&panel), std::slice::from_ref(&flat), kernel::BoolOp::Intersect, &mut work)?;
+                        sheet::material_boolean(std::slice::from_ref(&local), std::slice::from_ref(&flat), kernel::BoolOp::Intersect, &mut work)?;
                     if !clipped.is_empty() && !depth_resolved {
                         return Err(DocError::Invalid(
                             "sheet machining depth is below the supported 0.000001 mm extrusion resolution; increase the layer depth".into(),

crates/doc/src/sheet.rs

@@ -166,6 +166,46 @@ fn regions_complexity<'a>(regions: impl Iterator<Item = &'a Region2>) -> Result<
     Ok((edges, points))
 }
 
+/// A flat region's cut-outs by their bounding boxes, to clip tools against only the ones near
+/// them (the result is the same: a cut-out clear of a tool's box can't change what it meets).
+pub(crate) struct NearHoles<'a> {
+    region: &'a Region2,
+    boxes: Vec<(Vec2, Vec2)>,
+}
+
+/// A loop's bounding box, a little larger than its chords so arcs stay inside.
+fn loop_box(lp: &Loop2) -> Result<(Vec2, Vec2)> {
+    let pts = flat_polyline(lp)?;
+    let (lo, hi) = pts.iter().fold((Vec2::new(f64::MAX, f64::MAX), Vec2::new(f64::MIN, f64::MIN)), |(lo, hi), p| {
+        (Vec2::new(lo.x.min(p.x), lo.y.min(p.y)), Vec2::new(hi.x.max(p.x), hi.y.max(p.y)))
+    });
+    let pad = 1e-3 + 1e-9 * (lo.x.abs() + lo.y.abs() + hi.x.abs() + hi.y.abs());
+    Ok((lo - Vec2::new(pad, pad), hi + Vec2::new(pad, pad)))
+}
+
+impl<'a> NearHoles<'a> {
+    pub(crate) fn new(region: &'a Region2) -> Result<Self> {
+        Ok(Self { region, boxes: region.holes.iter().map(loop_box).collect::<Result<_>>()? })
+    }
+
+    /// The region with only the cut-outs whose boxes meet `tool`'s.
+    pub(crate) fn around(&self, tool: &Region2) -> Result<Region2> {
+        if self.region.holes.is_empty() {
+            return Ok(self.region.clone());
+        }
+        let (lo, hi) = loop_box(&tool.outer)?;
+        let holes = self
+            .region
+            .holes
+            .iter()
+            .zip(&self.boxes)
+            .filter(|(_, (a, b))| a.x <= hi.x && b.x >= lo.x && a.y <= hi.y && b.y >= lo.y)
+            .map(|(h, _)| h.clone())
+            .collect();
+        Ok(Region2 { outer: self.region.outer.clone(), holes })
+    }
+}
+
 pub(crate) fn material_boolean(a: &[Region2], b: &[Region2], op: kernel::BoolOp, work: &mut FlatWork) -> Result<Vec<Region2>> {
     let (ae, ap) = region_complexity(a)?;
     let (be, bp) = region_complexity(b)?;