bherbruck
d71bdb78ec
Preserve linked sketch identities through deterministic face projection and resizing. Fix origin-corner picking, persistent inline navigation, appearance editing, configuration styles, component properties, contact sweeps, sheet exports, analytic STEP offsets, and bounded rolling-ball fit accuracy. Validated with full cargo xtask ci, native workflow screenshots, repeated enclosure replays, and analytic geometry regressions.
722 lines
36 KiB
Rust
722 lines
36 KiB
Rust
//! Rolling-ball blends along a closed chain of smooth edges between two smooth groups of faces
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//! of any surfaces (a branch pipe meeting a main pipe, a boss on a cylinder). A ball of the
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//! blend's radius rolls along the edge touching both sides; its centre traces the spine and its
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//! contacts the curves where the blend meets each side. The blend face is a rational B-spline
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//! through the circular cross-sections (exact arcs at the samples), the side faces are trimmed
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//! back to the contact curves, and seams that met the edge are shortened to the contacts.
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use std::collections::HashMap;
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use solvecraft_geom::Vec3;
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use truck_modeling::{self as mt, builder};
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use crate::body::{Solid, from_p3, p3};
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use crate::{KernelError, Result};
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fn unsupported(msg: &str) -> KernelError {
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KernelError::Failed(format!("not supported yet: {msg}"))
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}
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/// Samples per edge for the contact curves and the blend surface.
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const SAMPLES: usize = 24;
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const MAX_SAMPLES: usize = 369;
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const MAX_CHAIN_SAMPLES: usize = 100_000;
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struct Fit {
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surface: mt::Surface,
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contacts: [mt::Curve; 2],
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/// Parameter range belonging to this edge (the fit includes neighbouring sections).
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range: (f64, f64),
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}
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struct Guide {
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sections: Vec<Section>,
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lengths: Vec<f64>,
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}
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impl Guide {
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fn new(sections: Vec<Section>) -> Result<Self> {
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let mut lengths = vec![0.0];
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let mut total = 0.0;
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for pair in sections.windows(2) {
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let (Some(a), Some(b)) = (pair.first(), pair.get(1)) else { continue };
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total += a.c.dist(b.c);
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lengths.push(total);
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}
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if !total.is_finite() || total <= 1e-12 {
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return Err(unsupported("degenerate rolling-ball spine"));
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}
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Ok(Self { sections, lengths })
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}
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fn anchor(&self, along: f64) -> Option<(Vec3, Vec3)> {
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if self.lengths.len() < 2 || !along.is_finite() || !(0.0..=1.0).contains(&along) {
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return None;
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}
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let distance = self.lengths.last()? * along;
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let hi = self.lengths.partition_point(|length| *length < distance).clamp(1, self.lengths.len().checked_sub(1)?);
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let (a, b) = (self.sections.get(hi - 1)?, self.sections.get(hi)?);
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let (lo, hi_length) = (self.lengths.get(hi - 1)?, self.lengths.get(hi)?);
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let span = hi_length - lo;
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if span <= 1e-12 {
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return None;
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}
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let fraction = (distance - lo) / span;
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Some((a.c + (b.c - a.c) * fraction, (b.c - a.c).normalized()?))
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}
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}
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/// One interpolation for both the face and its boundary curves. Fitting the contacts
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/// independently gives different end conditions and leaves gaps between the same faces.
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fn fit_sections(sections: &[Vec<Section>], k: usize, closed: bool, round: bool) -> Result<Fit> {
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use mt::Cut;
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let fail = |m: &str| KernelError::Failed(format!("curve blend: {m}"));
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let n = sections.len();
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let list = sections.get(k).ok_or_else(|| fail("section"))?;
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let before = usize::from(closed || k > 0) * 2;
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let mut ext = Vec::with_capacity(list.len() + 4);
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if before > 0 {
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let prev = sections.get((k + n - 1) % n).ok_or_else(|| fail("section"))?;
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ext.extend(prev.iter().rev().skip(1).take(2).rev().copied());
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}
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ext.extend(list.iter().copied());
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if closed || k + 1 < n {
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let next = sections.get((k + 1) % n).ok_or_else(|| fail("section"))?;
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ext.extend(next.iter().skip(1).take(2).copied());
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}
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let ctrl: Vec<[mt::Vector4; 3]> = ext.iter().map(|s| section_controls(s, round)).collect::<Option<_>>().ok_or_else(|| fail("section"))?;
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let mut rows = Vec::with_capacity(3);
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let mut vknots = None;
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for j in 0..3 {
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let xyz: Vec<Vec3> = ctrl.iter().filter_map(|c| c.get(j)).map(|c| Vec3::new(c.x, c.y, c.z)).collect();
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let ww: Vec<Vec3> = ctrl.iter().filter_map(|c| c.get(j)).map(|c| Vec3::new(c.w, 0.0, 0.0)).collect();
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let bx = crate::build::interpolate_cubic(&xyz).ok_or_else(|| fail("blend surface"))?;
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let bw = crate::build::interpolate_cubic(&ww).ok_or_else(|| fail("blend surface"))?;
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vknots = Some(bx.knot_vec().clone());
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rows.push(bx.control_points().iter().zip(bw.control_points()).map(|(p, w)| mt::Vector4::new(p.x, p.y, p.z, w.x)).collect::<Vec<_>>());
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}
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let vk = vknots.ok_or_else(|| fail("knots"))?;
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let den = ext.len().saturating_sub(1) as f64;
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if den <= 0.0 {
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return Err(fail("empty sections"));
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}
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let range = (before as f64 / den, (before + list.len().saturating_sub(1)) as f64 / den);
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let contact = |row: usize| -> Result<mt::Curve> {
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let points = rows.get(row).cloned().ok_or_else(|| fail("contact row"))?;
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let bs = mt::BSplineCurve::try_new(vk.clone(), points).map_err(|e| fail(&e.to_string()))?;
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let mut curve = mt::NurbsCurve::new(bs);
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if range.0 > 0.0 {
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curve = curve.cut(range.0);
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}
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if range.1 < 1.0 {
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let _ = curve.cut(range.1);
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}
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Ok(mt::Curve::NurbsCurve(curve))
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};
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let contacts = [contact(0)?, contact(2)?];
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let bs = mt::BSplineSurface::try_new((mt::KnotVec::bezier_knot(2), vk), rows).map_err(|e| fail(&e.to_string()))?;
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Ok(Fit { surface: mt::Surface::NurbsSurface(mt::NurbsSurface::new(bs)), contacts, range })
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}
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/// Compare the fitted strip with a solved circular section between interpolation nodes.
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/// This checks the supporting contacts as well as the middle of the fillet band.
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fn section_fits(fit: &Fit, section: &Section, along: f64, round: bool, sigma: f64, tolerance: f64) -> bool {
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use mt::{ParametricSurface, ParametricSurface3D, SearchNearestParameter};
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let Some(ctrl) = section_controls(section, round) else { return false };
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let v = fit.range.0 + (fit.range.1 - fit.range.0) * along;
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for u in [0.0, 0.25, 0.5, 0.75, 1.0] {
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let [a, b, c] = ctrl;
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let h = a * (1.0 - u) * (1.0 - u) + b * (2.0 * u * (1.0 - u)) + c * u * u;
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if !h.w.is_finite() || h.w <= 1e-12 {
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return false;
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}
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let exact = Vec3::new(h.x / h.w, h.y / h.w, h.z / h.w);
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// The input intersection edge may use piecewise leader-curve parameters. A
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// parameter-speed change is not a geometric error: compare nearest points, with
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// contacts constrained to the corresponding boundary and all probes to the strip.
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let (probe_u, probe_v) = if u == 0.0 || u == 1.0 {
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let Some(contact) = fit.contacts.get(usize::from(u == 1.0)) else { return false };
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let Some(parameter) = contact.search_nearest_parameter(p3(exact), v, 32) else { return false };
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(u, parameter.clamp(fit.range.0, fit.range.1))
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} else {
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let Some((pu, pv)) = fit.surface.search_nearest_parameter(p3(exact), Some((u, v)), 32) else { return false };
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(pu.clamp(0.0, 1.0), pv.clamp(fit.range.0, fit.range.1))
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};
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let actual = from_p3(fit.surface.subs(probe_u, probe_v));
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if !actual.is_finite() || actual.dist(exact) > tolerance {
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return false;
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}
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if round && (u == 0.0 || u == 1.0) {
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let Some(want) = ((section.c - exact) * sigma).normalized() else { return false };
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let normal = fit.surface.normal(probe_u, probe_v);
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let Some(normal) = Vec3::new(normal.x, normal.y, normal.z).normalized() else { return false };
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if normal.dot(want).abs() < 0.5f64.to_radians().cos() {
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return false;
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}
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}
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}
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true
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}
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/// One cross-section of the blend: ball centre and its contacts with side 1 and side 2.
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#[derive(Clone, Copy, Debug)]
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struct Section {
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c: Vec3,
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q1: Vec3,
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q2: Vec3,
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}
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/// Nearest point of a face's surface and the outward normal there.
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fn project(f: &mt::Face, p: Vec3, hint: Option<(f64, f64)>) -> Option<(Vec3, Vec3, (f64, f64))> {
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use mt::{ParametricSurface, ParametricSurface3D, SearchNearestParameter};
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let s = f.oriented_surface();
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let uv = s.search_nearest_parameter(p3(p), hint, 100).or_else(|| s.search_nearest_parameter(p3(p), None, 100))?;
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let q = from_p3(s.subs(uv.0, uv.1));
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let n = s.normal(uv.0, uv.1);
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Some((q, Vec3::new(n.x, n.y, n.z).normalized()?, uv))
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}
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/// Solve for the ball touching both sides near `p`. `extra` adds a third condition (a plane the
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/// side-k contact must lie in); without it the centre stays in the plane through `p` square to
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/// `t`. `sigma` is +1 when the ball sits outside the material (concave edge), −1 inside.
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#[allow(clippy::too_many_arguments)]
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fn solve(f1: &[&mt::Face], f2: &[&mt::Face], p: Vec3, t: Vec3, r: f64, sigma: f64, extra: Option<(usize, Vec3, Vec3)>, tol: f64) -> Option<Section> {
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// The nearest face of a side (several faces on one smooth surface group).
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let near = |fs: &[&mt::Face], c: Vec3| -> Option<(Vec3, Vec3)> {
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fs.iter().filter_map(|f| project(f, c, None).map(|(q, n, _)| (q, n))).min_by(|a, b| a.0.dist(c).total_cmp(&b.0.dist(c)))
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};
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let (q1, n1) = near(f1, p)?;
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let (q2, n2) = near(f2, p)?;
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let _ = (q1, q2);
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let den = 1.0 + n1.dot(n2);
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if den.abs() < 1e-9 {
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return None;
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}
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let mut c = p + (n1 + n2) * (sigma * r / den);
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for _ in 0..60 {
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let (q1, n1) = near(f1, c)?;
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let (q2, n2) = near(f2, c)?;
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let g1 = (c - q1).dot(n1) - sigma * r;
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let g2 = (c - q2).dot(n2) - sigma * r;
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// Third row: stay in the section plane, or put a contact on the seam plane.
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let (row3, g3) = match extra {
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None => (t, (c - p).dot(t)),
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Some((k, o, m)) => {
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let q = if k == 1 { q1 } else { q2 };
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(m, (q - o).dot(m))
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}
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};
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let a = [[n1.x, n1.y, n1.z], [n2.x, n2.y, n2.z], [row3.x, row3.y, row3.z]];
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let b = [-g1, -g2, -g3];
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let x = crate::polyhedron::solve3_pub(a, b)?;
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let dc = Vec3::new(x[0], x[1], x[2]);
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c += dc;
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if dc.len() < tol * 1e-3 && g1.abs() < tol && g2.abs() < tol && g3.abs() < tol {
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let (q1, _) = near(f1, c)?;
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let (q2, _) = near(f2, c)?;
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return Some(Section { c, q1, q2 });
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}
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}
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None
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}
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/// Homogeneous control points of the circular (or straight) cross-section from q1 to q2.
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fn section_controls(s: &Section, round: bool) -> Option<[mt::Vector4; 3]> {
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let h = |p: Vec3, w: f64| mt::Vector4::new(p.x * w, p.y * w, p.z * w, w);
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if !round {
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let m = (s.q1 + s.q2) * 0.5;
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return Some([h(s.q1, 1.0), h(m, 1.0), h(s.q2, 1.0)]);
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}
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let (a, b) = (s.q1 - s.c, s.q2 - s.c);
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let theta = a.normalized()?.dot(b.normalized()?).clamp(-1.0, 1.0).acos();
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if !(theta > 1e-6 && theta < std::f64::consts::PI - 1e-6) {
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return None;
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}
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let half = (theta / 2.0).cos();
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let bis = (a + b).normalized()?;
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let m = s.c + bis * (a.len() / half);
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Some([h(s.q1, 1.0), h(m, half), h(s.q2, 1.0)])
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}
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/// Blend the closed chain of edges (ids in any order) with radius `r`.
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pub(crate) fn curve_blend(solid: &Solid, ids: &[mt::EdgeID], size: f64, r: f64, round: bool) -> Result<Solid> {
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curve_blend_with_limit(solid, ids, size, r, round, MAX_SAMPLES)
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}
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fn curve_blend_with_limit(solid: &Solid, ids: &[mt::EdgeID], size: f64, r: f64, round: bool, max_samples: usize) -> Result<Solid> {
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if !(size.is_finite() && size > 0.0 && r.is_finite() && r > 0.0) {
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return Err(KernelError::Invalid("curve blend size and radius must be finite and positive".into()));
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}
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if !(4..=MAX_SAMPLES).contains(&max_samples) {
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return Err(KernelError::Invalid("curve blend section limit is outside the supported range".into()));
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}
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let tol = (size * 1e-7).max(1e-9);
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let shells = solid.boundaries();
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let (si, shell) = shells
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.iter()
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.enumerate()
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.find(|(_, sh)| sh.edge_iter().any(|e| ids.contains(&e.id())))
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.ok_or_else(|| KernelError::Failed("edge not found".into()))?;
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let faces: Vec<mt::Face> = shell.face_iter().cloned().collect();
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// Order the chain: edges as stored (absolute direction), each starting where the last ended.
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let mut chain: Vec<mt::Edge> = Vec::new();
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let all: Vec<mt::Edge> = {
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let mut seen = std::collections::HashSet::new();
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shell.edge_iter().filter(|e| ids.contains(&e.id()) && seen.insert(e.id())).map(|e| e.absolute_clone()).collect()
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};
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// An open chain starts at a vertex only one of its edges touches.
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let uses = |v: &mt::Vertex| all.iter().filter(|e| e.front() == v || e.back() == v).count();
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let first = match all.iter().find_map(|e| {
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if uses(e.front()) == 1 {
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Some(e.clone())
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} else if uses(e.back()) == 1 {
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Some(e.inverse())
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} else {
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None
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}
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}) {
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Some(e) => e,
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None => all.first().cloned().ok_or_else(|| KernelError::Failed("no edges".into()))?,
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};
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chain.push(first.clone());
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while chain.len() < all.len() {
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let end = chain.last().map(|e| e.back().clone()).ok_or_else(|| KernelError::Failed("chain".into()))?;
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let next = all
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.iter()
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.find(|e| !chain.iter().any(|c| c.id() == e.id()) && (*e.front() == end || *e.back() == end))
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.ok_or_else(|| unsupported("the edges don't form one chain"))?;
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chain.push(if *next.front() == end { next.clone() } else { next.inverse() });
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}
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let closed = chain.first().map(|e| e.front().clone()) == chain.last().map(|e| e.back().clone());
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let n = chain.len();
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// The chain's vertices (n for a closed chain, n + 1 for an open one).
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let mut verts: Vec<mt::Vertex> = chain.iter().map(|e| e.front().clone()).collect();
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if !closed && let Some(e) = chain.last() {
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verts.push(e.back().clone());
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}
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let nv = verts.len();
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// Faces of each edge, split into the two sides.
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let faces_of = |e: &mt::Edge| -> Vec<usize> {
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(0..faces.len()).filter(|i| faces.get(*i).is_some_and(|f| f.edge_iter().any(|x| x.id() == e.id()))).collect()
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};
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let mut side1: Vec<usize> = Vec::new();
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let mut side2: Vec<usize> = Vec::new();
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for (k, e) in chain.iter().enumerate() {
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let fs = faces_of(e);
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let [a, b] = fs[..] else { return Err(unsupported("an edge without two faces")) };
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if k == 0 {
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side1.push(a);
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side2.push(b);
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continue;
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}
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// The side-1 face of this edge is the one whose normal matches side 1 at the joint.
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let p = from_p3(e.front().point());
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let nrm = |fi: usize| faces.get(fi).and_then(|f| project(f, p, None)).map(|x| x.1);
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let prev1 = side1.last().copied().and_then(nrm);
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let (na, nb) = (nrm(a), nrm(b));
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let a_is_1 = match (prev1, na, nb) {
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(Some(x), Some(y), Some(z)) => x.dot(y) >= x.dot(z),
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_ => return Err(KernelError::Failed("blend: normals".into())),
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};
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if a_is_1 {
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side1.push(a);
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side2.push(b);
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} else {
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side1.push(b);
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side2.push(a);
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}
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}
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let s1: Vec<&mt::Face> = side1.iter().filter_map(|i| faces.get(*i)).collect();
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let s2: Vec<&mt::Face> = side2.iter().filter_map(|i| faces.get(*i)).collect();
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// Convex or concave, from the first edge as its side-1 face runs it.
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let e0 = chain.first().ok_or_else(|| KernelError::Failed("chain".into()))?;
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let f1 = s1.first().ok_or_else(|| KernelError::Failed("side".into()))?;
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let in_f1 = f1.boundary_iters().into_iter().flatten().find(|e| e.id() == e0.id()).ok_or_else(|| KernelError::Failed("edge use".into()))?;
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let (pm, t1) = {
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use mt::{BoundedCurve, ParametricCurve};
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let c = in_f1.oriented_curve();
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let (a, b) = c.range_tuple();
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let m = (a + b) * 0.5;
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let d = c.der(m);
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(from_p3(c.subs(m)), Vec3::new(d.x, d.y, d.z).normalized().ok_or_else(|| KernelError::Failed("tangent".into()))?)
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};
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let (n1, n2) = match (project(f1, pm, None), s2.first().and_then(|f| project(f, pm, None))) {
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(Some(x), Some(y)) => (x.1, y.1),
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_ => return Err(KernelError::Failed("blend: normals".into())),
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};
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let convex = t1.dot(n1.cross(n2)) > 0.0;
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let sigma = if convex { -1.0 } else { 1.0 };
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if n1.dot(n2) > 1.0 - 1e-6 {
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return Err(unsupported("blending a smooth edge"));
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}
|
||
// Seams at the chain's vertices: edges there that aren't in the chain, and their side.
|
||
let chain_ids: Vec<mt::EdgeID> = chain.iter().map(|e| e.id()).collect();
|
||
let mut seams: Vec<Vec<(usize, mt::Edge)>> = Vec::with_capacity(nv);
|
||
// At an open chain's ends: the end face (planar, square to the edge there).
|
||
let mut end_faces: Vec<(usize, usize)> = Vec::new(); // (vertex index, face index)
|
||
for (k, v) in verts.iter().enumerate() {
|
||
let at_end = !closed && (k == 0 || k == nv - 1);
|
||
let (k1, k2) = {
|
||
let ei = if k == nv - 1 && !closed { n - 1 } else { k.min(n - 1) };
|
||
(side1.get(ei).copied().unwrap_or(usize::MAX), side2.get(ei).copied().unwrap_or(usize::MAX))
|
||
};
|
||
let mut found: Vec<(usize, mt::Edge)> = Vec::new();
|
||
for (fi, f) in faces.iter().enumerate() {
|
||
if !f.vertex_iter().any(|x| x == *v) {
|
||
continue;
|
||
}
|
||
let on_side = side1.contains(&fi) || side2.contains(&fi);
|
||
if !on_side {
|
||
if !at_end || end_faces.iter().any(|(kk, _)| *kk == k) {
|
||
return Err(unsupported("a vertex of the edge chain where other faces meet"));
|
||
}
|
||
end_faces.push((k, fi));
|
||
continue;
|
||
}
|
||
for x in f.edge_iter() {
|
||
if chain_ids.contains(&x.id()) || !(*x.front() == *v || *x.back() == *v) || found.iter().any(|(_, y)| y.id() == x.id()) {
|
||
continue;
|
||
}
|
||
let side = if fi == k1 || (side1.contains(&fi) && fi != k2) { 1 } else { 2 };
|
||
found.push((side, x.absolute_clone()));
|
||
}
|
||
}
|
||
if at_end && !end_faces.iter().any(|(kk, _)| *kk == k) {
|
||
return Err(unsupported("an open chain of curved edges must end at a face"));
|
||
}
|
||
// At most one seam per side.
|
||
if found.iter().filter(|x| x.0 == 1).count() > 1 || found.iter().filter(|x| x.0 == 2).count() > 1 {
|
||
return Err(unsupported("a vertex of the edge chain where several seams meet"));
|
||
}
|
||
seams.push(found);
|
||
}
|
||
// Sections: at each vertex (a contact on the seam there), then along each edge.
|
||
let tangent_at = |e: &mt::Edge, s: f64| -> Option<(Vec3, Vec3)> {
|
||
use mt::{BoundedCurve, ParametricCurve};
|
||
let c = e.oriented_curve();
|
||
let (a, b) = c.range_tuple();
|
||
let t = a + (b - a) * s;
|
||
let d = c.der(t);
|
||
Some((from_p3(c.subs(t)), Vec3::new(d.x, d.y, d.z).normalized()?))
|
||
};
|
||
let mut vsec: Vec<Section> = Vec::with_capacity(nv);
|
||
for k in 0..nv {
|
||
let (p, t) = if k < n {
|
||
tangent_at(chain.get(k).ok_or_else(|| KernelError::Failed("edge".into()))?, 0.0)
|
||
} else {
|
||
tangent_at(chain.get(n - 1).ok_or_else(|| KernelError::Failed("edge".into()))?, 1.0)
|
||
}
|
||
.ok_or_else(|| KernelError::Failed("tangent".into()))?;
|
||
let here = seams.get(k).cloned().unwrap_or_default();
|
||
let at_end = end_faces.iter().any(|(kk, _)| *kk == k);
|
||
if at_end {
|
||
// The end face must be square to the edge: the blend's end then lies in it.
|
||
let (_, fi) = end_faces.iter().find(|(kk, _)| *kk == k).copied().unwrap_or_default();
|
||
let g = faces.get(fi).ok_or_else(|| KernelError::Failed("end face".into()))?;
|
||
let ng = match g.oriented_surface() {
|
||
mt::Surface::Plane(pl) => {
|
||
let m = pl.normal();
|
||
Vec3::new(m.x, m.y, m.z).normalized()
|
||
}
|
||
_ => None,
|
||
}
|
||
.ok_or_else(|| unsupported("the faces at the ends of the edges must be planar"))?;
|
||
if ng.dot(t).abs() < 1.0 - 1e-6 {
|
||
return Err(unsupported("the faces at the ends of the edges must be square to them"));
|
||
}
|
||
}
|
||
let extra = match here.first().cloned().filter(|_| !at_end) {
|
||
None => None,
|
||
Some((side, seam)) => {
|
||
// The plane through the seam square to that side's surface.
|
||
let o = from_p3(seam.front().point());
|
||
let d = (from_p3(seam.back().point()) - o).normalized().ok_or_else(|| KernelError::Failed("seam".into()))?;
|
||
if !matches!(seam.curve(), mt::Curve::Line(_)) {
|
||
return Err(unsupported("a curved seam where the edge chain turns"));
|
||
}
|
||
let fs = if side == 1 { &s1 } else { &s2 };
|
||
let nn =
|
||
fs.iter().filter_map(|f| project(f, p, None)).map(|x| x.1).next().ok_or_else(|| KernelError::Failed("seam normal".into()))?;
|
||
Some((side, o, d.cross(nn).normalized().ok_or_else(|| KernelError::Failed("seam plane".into()))?))
|
||
}
|
||
};
|
||
let s = solve(&s1, &s2, p, t, r, sigma, extra, tol * 100.0).ok_or_else(|| unsupported("the ball doesn't fit along the edge"))?;
|
||
// A seam on the other side too must pass through that side's contact.
|
||
if let Some((side, seam)) = here.get(1).filter(|_| !at_end) {
|
||
let q = if *side == 1 { s.q1 } else { s.q2 };
|
||
let (a, b) = (from_p3(seam.front().point()), from_p3(seam.back().point()));
|
||
if !matches!(seam.curve(), mt::Curve::Line(_)) || q.dist_to_segment(a, b) > tol * 1e3 {
|
||
return Err(unsupported("seams on both sides of a corner of the edge chain"));
|
||
}
|
||
}
|
||
vsec.push(s);
|
||
}
|
||
// Uniform refinement preserves a common spacing across neighbouring patches. Work is
|
||
// capped: a difficult strip returns an error instead of accepting an inaccurate fit.
|
||
let fit_tolerance = (size * 1e-5).clamp(1e-5, 0.001);
|
||
// At a seam the contact lies on the seam plane, which need not be square to the
|
||
// original edge. Its ball centre therefore need not lie in the edge's normal plane.
|
||
// Interpolate that plane's displacement so the interior sections tend to the exact
|
||
// seam sections, rather than leaving a finite jump as sampling gets finer.
|
||
let offsets: Vec<(f64, f64)> = chain
|
||
.iter()
|
||
.enumerate()
|
||
.map(|(k, edge)| {
|
||
let (p0, t0) = tangent_at(edge, 0.0).ok_or_else(|| KernelError::Failed("tangent".into()))?;
|
||
let (p1, t1) = tangent_at(edge, 1.0).ok_or_else(|| KernelError::Failed("tangent".into()))?;
|
||
let start = vsec.get(k).ok_or_else(|| KernelError::Failed("section".into()))?;
|
||
let end = vsec.get((k + 1) % nv).ok_or_else(|| KernelError::Failed("section".into()))?;
|
||
Ok(((start.c - p0).dot(t0), (end.c - p1).dot(t1)))
|
||
})
|
||
.collect::<Result<_>>()?;
|
||
let section_at = |k: usize, edge: &mt::Edge, along: f64| -> Result<Section> {
|
||
let (p, t) = tangent_at(edge, along).ok_or_else(|| KernelError::Failed("tangent".into()))?;
|
||
let (start, end) = offsets.get(k).copied().ok_or_else(|| KernelError::Failed("section offset".into()))?;
|
||
let anchor = p + t * (start * (1.0 - along) + end * along);
|
||
solve(&s1, &s2, anchor, t, r, sigma, None, tol * 100.0).ok_or_else(|| unsupported("the ball doesn't fit along the edge"))
|
||
};
|
||
let mut samples = SAMPLES.min(max_samples);
|
||
let (esec, fits) = loop {
|
||
if n.checked_mul(samples).is_none_or(|count| count > MAX_CHAIN_SAMPLES) {
|
||
return Err(unsupported("curve blend exceeds the section fitting limit"));
|
||
}
|
||
let mut guides = Vec::with_capacity(n);
|
||
for (k, e) in chain.iter().enumerate() {
|
||
let mut list = vec![*vsec.get(k).ok_or_else(|| KernelError::Failed("section".into()))?];
|
||
for j in 1..samples - 1 {
|
||
list.push(section_at(k, e, j as f64 / (samples - 1) as f64)?);
|
||
}
|
||
list.push(*vsec.get((k + 1) % nv).ok_or_else(|| KernelError::Failed("section".into()))?);
|
||
guides.push(Guide::new(list)?);
|
||
}
|
||
// Intersection curves inherit their leader's piecewise parameter speed. Fitting
|
||
// those parameters creates oscillations even on a geometrically smooth spine.
|
||
// Resample by distance along the rolling centres, projecting each interpolated
|
||
// centre back onto the exact two offset surfaces before it becomes a section.
|
||
let uniform_section = |k: usize, along: f64| -> Result<Section> {
|
||
let guide = guides.get(k).ok_or_else(|| KernelError::Failed("spine guide".into()))?;
|
||
if along == 0.0 {
|
||
return guide.sections.first().copied().ok_or_else(|| KernelError::Failed("section".into()));
|
||
}
|
||
if along == 1.0 {
|
||
return guide.sections.last().copied().ok_or_else(|| KernelError::Failed("section".into()));
|
||
}
|
||
let (anchor, tangent) = guide.anchor(along).ok_or_else(|| unsupported("degenerate rolling-ball spine"))?;
|
||
solve(&s1, &s2, anchor, tangent, r, sigma, None, tol * 100.0).ok_or_else(|| unsupported("the ball doesn't fit along the resampled spine"))
|
||
};
|
||
let esec: Vec<Vec<Section>> = (0..n)
|
||
.map(|k| (0..samples).map(|j| uniform_section(k, j as f64 / (samples - 1) as f64)).collect::<Result<Vec<_>>>())
|
||
.collect::<Result<_>>()?;
|
||
let fits = crate::guard("fit curve blend", || (0..n).map(|k| fit_sections(&esec, k, closed, round)).collect::<Result<Vec<_>>>())?;
|
||
let mut accurate = true;
|
||
'edges: for k in 0..n {
|
||
let fit = fits.get(k).ok_or_else(|| KernelError::Failed("curve blend fit".into()))?;
|
||
for j in 0..samples - 1 {
|
||
for fraction in [0.25, 0.5, 0.75] {
|
||
let along = (j as f64 + fraction) / (samples - 1) as f64;
|
||
let section = uniform_section(k, along)?;
|
||
if !crate::guard("check curve blend fit", || Ok(section_fits(fit, §ion, along, round, sigma, fit_tolerance)))? {
|
||
accurate = false;
|
||
break 'edges;
|
||
}
|
||
}
|
||
}
|
||
}
|
||
if accurate {
|
||
break (esec, fits);
|
||
}
|
||
if samples >= max_samples {
|
||
return Err(KernelError::Failed("curve blend: could not fit the rolling-ball surface within the accuracy and section limits".into()));
|
||
}
|
||
samples = (2 * samples - 1).min(max_samples);
|
||
};
|
||
crate::guard("curve blend", || {
|
||
let fail = |m: &str| KernelError::Failed(format!("curve blend: {m}"));
|
||
// Vertices and arcs at the chain's vertices.
|
||
let v1: Vec<mt::Vertex> = vsec.iter().map(|s| builder::vertex(p3(s.q1))).collect();
|
||
let v2: Vec<mt::Vertex> = vsec.iter().map(|s| builder::vertex(p3(s.q2))).collect();
|
||
let mut arcs = Vec::with_capacity(nv);
|
||
for (k, s) in vsec.iter().enumerate() {
|
||
let (a, b) = (v1.get(k).ok_or_else(|| fail("vertex"))?, v2.get(k).ok_or_else(|| fail("vertex"))?);
|
||
let e = if round {
|
||
let m = s.c + ((s.q1 - s.c) + (s.q2 - s.c)).normalized().ok_or_else(|| fail("arc"))? * r;
|
||
builder::circle_arc(a, b, p3(m))
|
||
} else {
|
||
builder::line(a, b)
|
||
};
|
||
arcs.push(e);
|
||
}
|
||
// Contact curves and blend faces per edge.
|
||
let mut c1: Vec<mt::Edge> = Vec::with_capacity(n);
|
||
let mut c2: Vec<mt::Edge> = Vec::with_capacity(n);
|
||
let mut blends: Vec<mt::Surface> = Vec::with_capacity(n);
|
||
for (k, list) in esec.iter().enumerate() {
|
||
let k1 = (k + 1) % nv;
|
||
let (a1, b1, a2, b2) = (v1.get(k), v1.get(k1), v2.get(k), v2.get(k1));
|
||
let (Some(a1), Some(b1), Some(a2), Some(b2)) = (a1, b1, a2, b2) else { return Err(fail("vertex")) };
|
||
let fit = fits.get(k).ok_or_else(|| fail("fit"))?;
|
||
let [cv1, cv2] = &fit.contacts;
|
||
let e1 = mt::Edge::new(a1, b1, cv1.clone());
|
||
let e2 = mt::Edge::new(a2, b2, cv2.clone());
|
||
let mut surface = fit.surface.clone();
|
||
// Outward: toward the ball centre on a concave edge, away on a convex one.
|
||
{
|
||
use mt::{ParametricSurface3D, SearchNearestParameter};
|
||
let s = list.get(list.len() / 2).ok_or_else(|| fail("section"))?;
|
||
let mid = s.c + ((s.q1 - s.c) + (s.q2 - s.c)).normalized().ok_or_else(|| fail("mid"))? * r;
|
||
if let Some((u, v)) = surface.search_nearest_parameter(p3(mid), None, 100) {
|
||
let nn = surface.normal(u, v);
|
||
let want = (s.c - mid) * sigma;
|
||
if Vec3::new(nn.x, nn.y, nn.z).dot(want) < 0.0 {
|
||
surface = mt::Invertible::inverse(&surface);
|
||
}
|
||
}
|
||
}
|
||
c1.push(e1);
|
||
c2.push(e2);
|
||
blends.push(surface);
|
||
}
|
||
// Rebuild the side faces: chain edges become contact curves, seams start at contacts.
|
||
let mut subst: HashMap<mt::EdgeID, (mt::Edge, mt::Edge)> = HashMap::new();
|
||
for (k, e) in chain.iter().enumerate() {
|
||
let (Some(x), Some(y)) = (c1.get(k), c2.get(k)) else { return Err(fail("contact")) };
|
||
subst.insert(e.id(), (x.clone(), y.clone()));
|
||
}
|
||
// Seams get new ends at the contacts (an edge between two chain vertices at both).
|
||
let mut ends: HashMap<mt::EdgeID, (mt::Edge, Option<mt::Vertex>, Option<mt::Vertex>)> = HashMap::new();
|
||
for (k, sm) in seams.iter().enumerate().flat_map(|(k, l)| l.iter().map(move |x| (k, x))) {
|
||
let (side, seam) = sm;
|
||
let v = verts.get(k).cloned().ok_or_else(|| fail("vertex"))?;
|
||
let nv = if *side == 1 { v1.get(k) } else { v2.get(k) }.ok_or_else(|| fail("vertex"))?.clone();
|
||
let slot = ends.entry(seam.id()).or_insert_with(|| (seam.clone(), None, None));
|
||
if *seam.front() == v {
|
||
slot.1 = Some(nv);
|
||
} else {
|
||
slot.2 = Some(nv);
|
||
}
|
||
}
|
||
let mut seam_subst: HashMap<mt::EdgeID, mt::Edge> = HashMap::new();
|
||
for (id, (seam, a, b)) in ends {
|
||
if !matches!(seam.curve(), mt::Curve::Line(_)) {
|
||
return Err(unsupported("a curved edge where the blend ends"));
|
||
}
|
||
// The new ends must stay on the seam, in order, short of each other.
|
||
let (p0, p1) = (from_p3(seam.front().point()), from_p3(seam.back().point()));
|
||
let at = |v: &mt::Vertex| {
|
||
let q = from_p3(v.point());
|
||
let d = p1 - p0;
|
||
((q - p0).dot(d) / d.len2().max(1e-300), (q - p0 - d * ((q - p0).dot(d) / d.len2().max(1e-300))).len())
|
||
};
|
||
let (ta, oa) = a.as_ref().map(at).unwrap_or((0.0, 0.0));
|
||
let (tb, ob) = b.as_ref().map(at).unwrap_or((1.0, 0.0));
|
||
if oa > size * 1e-5 || ob > size * 1e-5 || ta < -1e-9 || tb > 1.0 + 1e-9 || tb - ta < 1e-6 {
|
||
return Err(unsupported("the blend is larger than the neighbouring faces"));
|
||
}
|
||
let a = a.unwrap_or_else(|| seam.front().clone());
|
||
let b = b.unwrap_or_else(|| seam.back().clone());
|
||
seam_subst.insert(id, builder::line(&a, &b));
|
||
}
|
||
let mut out: Vec<mt::Face> = Vec::new();
|
||
for (fi, f) in faces.iter().enumerate() {
|
||
let corners: Vec<usize> = end_faces.iter().filter(|(_, g)| *g == fi).map(|(k, _)| *k).collect();
|
||
if !corners.is_empty() {
|
||
// The end face (one or both ends of the chain): its two edges at a chain end now
|
||
// stop at the contacts, with the blend's end arc between them.
|
||
let mut wires = Vec::new();
|
||
for w in f.absolute_boundaries() {
|
||
let mut es: Vec<mt::Edge> = Vec::new();
|
||
for e in w.edge_iter() {
|
||
let ne = match seam_subst.get(&e.id()) {
|
||
Some(s) => {
|
||
if e.front() == e.absolute_front() {
|
||
s.clone()
|
||
} else {
|
||
s.inverse()
|
||
}
|
||
}
|
||
None => e.clone(),
|
||
};
|
||
// Arriving at an old corner: continue along that end's arc.
|
||
let arrives = corners.iter().copied().find(|k| verts.get(*k).is_some_and(|v| *e.back() == *v));
|
||
es.push(ne.clone());
|
||
if let Some(k) = arrives {
|
||
let arc = arcs.get(k).ok_or_else(|| fail("arc"))?;
|
||
let (a1, a2) = (v1.get(k).ok_or_else(|| fail("vertex"))?, v2.get(k).ok_or_else(|| fail("vertex"))?);
|
||
let to = ne.back();
|
||
let corner = if to == a1 {
|
||
arc.clone()
|
||
} else if to == a2 {
|
||
arc.inverse()
|
||
} else {
|
||
return Err(fail("end face corner"));
|
||
};
|
||
es.push(corner);
|
||
}
|
||
}
|
||
wires.push(mt::Wire::from(es));
|
||
}
|
||
out.push(crate::heal::absolute_face(f, wires).ok_or_else(|| fail("an end face could not be rebuilt"))?);
|
||
continue;
|
||
}
|
||
let on1 = side1.contains(&fi);
|
||
let on2 = side2.contains(&fi);
|
||
if !on1 && !on2 && !f.edge_iter().any(|e| seam_subst.contains_key(&e.id())) {
|
||
out.push(f.clone());
|
||
continue;
|
||
}
|
||
let mut wires = Vec::new();
|
||
for w in f.absolute_boundaries() {
|
||
let mut es = Vec::new();
|
||
for e in w.edge_iter() {
|
||
let ne = if let Some((x, y)) = subst.get(&e.id()) {
|
||
let base = if on1 { x } else { y };
|
||
// Same direction as the chain edge, or reversed.
|
||
let chain_e = chain.iter().find(|c| c.id() == e.id()).ok_or_else(|| fail("edge"))?;
|
||
if e.front() == chain_e.front() { base.clone() } else { base.inverse() }
|
||
} else if let Some(s) = seam_subst.get(&e.id()) {
|
||
if e.front() == e.absolute_front() { s.clone() } else { s.inverse() }
|
||
} else {
|
||
e.clone()
|
||
};
|
||
es.push(ne);
|
||
}
|
||
wires.push(mt::Wire::from(es));
|
||
}
|
||
out.push(crate::heal::absolute_face(f, wires).ok_or_else(|| fail("a side face could not be rebuilt"))?);
|
||
}
|
||
// Blend faces: each runs its side-1 contact the other way from side 1's face.
|
||
for (k, bf) in blends.iter().enumerate() {
|
||
let (Some(e1), Some(e2), Some(ak), Some(ak1)) = (c1.get(k), c2.get(k), arcs.get(k), arcs.get((k + 1) % nv)) else {
|
||
return Err(fail("blend"));
|
||
};
|
||
let f1i = side1.get(k).ok_or_else(|| fail("side"))?;
|
||
let f1 = faces.get(*f1i).ok_or_else(|| fail("side"))?;
|
||
let chain_e = chain.get(k).ok_or_else(|| fail("edge"))?;
|
||
let used_fwd = f1
|
||
.boundary_iters()
|
||
.into_iter()
|
||
.flatten()
|
||
.find(|e| e.id() == chain_e.id())
|
||
.map(|e| e.front() == chain_e.front())
|
||
.ok_or_else(|| fail("edge use"))?;
|
||
// Side 1 runs the contact forward (as the chain) when it ran the edge forward.
|
||
let wire: mt::Wire = if used_fwd {
|
||
vec![e1.inverse(), ak.clone(), e2.clone(), ak1.inverse()].into()
|
||
} else {
|
||
vec![e1.clone(), ak1.clone(), e2.inverse(), ak.inverse()].into()
|
||
};
|
||
let face = mt::Face::try_new(vec![wire], bf.clone()).map_err(|e| fail(&e.to_string()))?;
|
||
out.push(face);
|
||
}
|
||
let mut shells = solid.boundaries().clone();
|
||
if let Some(sh) = shells.get_mut(si) {
|
||
*sh = out.into();
|
||
}
|
||
Solid::try_new(shells).map_err(|e| fail(&format!("invalid solid: {e}")))
|
||
})
|
||
}
|
||
|
||
#[cfg(test)]
|
||
#[path = "curveblend_tests.rs"]
|
||
mod tests;
|