bherbruckandClaude Opus 5.5
4b3b48388c
The groove's facets came in sweep order, and the BSP takes each list's first polygon as its splitter, so the tree was as deep as the list: quadratic time and memory. An M8 x 60 mm thread ran out of tree depth after 12.9 GB. A fixed shuffle gives a shallow tree and the same result (volume and faces equal to 1e-9). Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
65 lines
3.7 KiB
Rust
65 lines
3.7 KiB
Rust
//! Faceted booleans with helical tools (modelled threads).
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use std::f64::consts::PI;
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use solidcraft_geom::{Plane, Vec2, Vec3};
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use crate::{BoolOp, cylinder, faceted_boolean, sweep_helix_mesh};
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/// A trapezoid groove screwed into a shaft: the result is closed, and the volume removed is
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/// the section's 2π∫r dA per turn over the turns inside the shaft.
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#[test]
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fn faceted_cut_of_a_helical_groove() {
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let shaft = cylinder(Vec3::ZERO, Vec3::new(0.0, 0.0, 1.0), 1.5, 4.0).unwrap();
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let (p, k) = (0.5, Vec3::new(0.0, 0.0, 1.0));
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// From a turn under the shaft to its middle: 4.5 turns, the first half-turn in the air.
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let base = Vec3::new(0.0, 0.0, -p);
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let plane = Plane { origin: base, x: Vec3::new(1.0, 0.0, 0.0), y: k };
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let section = [Vec2::new(1.2, -0.06), Vec2::new(1.6, -0.06), Vec2::new(1.6, 0.06), Vec2::new(1.2, 0.06)];
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let groove = sweep_helix_mesh(&plane, §ion, base, k, p, 5.0, 48).unwrap();
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let cut = faceted_boolean(&shaft, &groove, BoolOp::Cut, 1e-3).unwrap().unwrap();
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let m = cut.tessellate(0.01).unwrap().measure();
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// In the shaft from z = 0: the section (r 1.2…1.5, 0.12 tall) for 4 turns, plus the part of
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// the first turn's section above z = 0 (its z range is ±0.06 about the turn's height).
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let per_turn = 2.0 * PI * 0.12 * (1.5f64.powi(2) - 1.2f64.powi(2)) / 2.0;
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let removed = PI * 2.25 * 4.0 - m.volume;
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assert!((removed - 4.0 * per_turn).abs() < 0.03 * per_turn * 4.0, "{removed} vs {}", 4.0 * per_turn);
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}
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/// A groove cut into the wall of a bore through a block (a nut): it runs out of both ends.
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#[test]
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fn faceted_cut_into_a_bore() {
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let nut = crate::box_solid(Vec3::new(-3.0, -3.0, 0.0), Vec3::new(3.0, 3.0, 2.0)).unwrap();
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let bore = cylinder(Vec3::new(0.0, 0.0, -1.0), Vec3::new(0.0, 0.0, 1.0), 1.23, 4.0).unwrap();
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let nut = crate::boolean(&nut, &bore, BoolOp::Cut).unwrap().unwrap();
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let v0 = nut.tessellate(1e-3).unwrap().measure().volume;
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let (p, k) = (0.5, Vec3::new(0.0, 0.0, 1.0));
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let base = Vec3::new(0.0, 0.0, -p);
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let plane = Plane { origin: base, x: Vec3::new(1.0, 0.0, 0.0), y: k };
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let section = [Vec2::new(1.1, -0.1), Vec2::new(1.5, -0.1), Vec2::new(1.5, 0.1), Vec2::new(1.1, 0.1)];
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let groove = sweep_helix_mesh(&plane, §ion, base, k, p, 6.0, 48).unwrap();
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let cut = faceted_boolean(&nut, &groove, BoolOp::Cut, 2.5e-3).unwrap().unwrap();
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let removed = v0 - cut.tessellate(1e-3).unwrap().measure().volume;
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// Four turns of the section's part outside the bore (r 1.23…1.5, 0.2 tall).
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let want = 4.0 * PI * 0.2 * (1.5f64.powi(2) - 1.23f64.powi(2));
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assert!((removed - want).abs() < 0.03 * want, "{removed} vs {want}");
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}
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/// #1250: a long thread (48 turns of an M8 groove on a 60 mm shaft). The groove's facets come in
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/// sweep order; taken as BSP splitters in that order they made the tree as deep as the facet
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/// list ("planar boolean: tree too deep", after minutes and gigabytes). It cuts now, closed.
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#[test]
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fn a_long_thread_cuts_without_a_deep_tree() {
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let (r, len, p) = (4.0, 60.0, 1.25);
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let shaft = cylinder(Vec3::ZERO, Vec3::new(0.0, 0.0, 1.0), r, len).unwrap();
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let k = Vec3::new(0.0, 0.0, 1.0);
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let base = Vec3::new(0.0, 0.0, -p);
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let plane = Plane { origin: base, x: Vec3::new(1.0, 0.0, 0.0), y: k };
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let section = [Vec2::new(3.3, -0.08), Vec2::new(4.1, -0.5), Vec2::new(4.1, 0.5), Vec2::new(3.3, 0.08)];
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let groove = sweep_helix_mesh(&plane, §ion, base, k, p, len / p + 2.0, 48).unwrap();
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let cut = faceted_boolean(&shaft, &groove, BoolOp::Cut, p * 0.005).unwrap().unwrap();
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let v = cut.tessellate(0.01).unwrap().measure().volume;
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let v0 = PI * r * r * len;
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assert!(v < v0 * 0.95 && v > v0 * 0.6, "{v} of {v0}");
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}
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