Iraklis KourtisandClaude Opus 5.5
a04ef4ca59
* Add B-spline basis, knot insertion and NURBS surfaces to geom Freeform faces need local refinement and gap-free joins between patches with different knot vectors, which tensor B-spline grids cannot give; T-splines can, and the first user is an N-sided Boundary Fill of non-planar loops. This lays the univariate groundwork they rest on, in the L0 geometry crate so it stays independent of the B-rep kernel: - Cox-de Boor basis of one function from its local knot vector, on half-open spans with a left-limit side for the domain end, with derivatives (NURBS Book eq. 2.5, 2.9) - knot insertion into a single basis function (Sederberg et al. 2004 section 3) and Bezier extraction of one function by repeated insertion - Boehm knot insertion for curves (NURBS Book A5.1), de Casteljau evaluation and sub-segments - a rational tensor NURBS surface with evaluation, knot insertion and clamping, and a rational Bezier patch type All input is checked (finite, monotone knots, positive weights, size caps) and returns SplineError; nothing indexes unchecked. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01J53sR6gEaVt56soFDpTck8 * Add T-spline surfaces: T-mesh, evaluation, AS check, refinement, extraction Tensor B-spline faces refine only by whole rows and columns and cannot join patches with different knot vectors without gaps. T-splines allow T-junctions in the control net, which fixes both; the first user is an N-sided Boundary Fill. This adds the maths only (no command, no change in behaviour): - T-mesh in index space with knot values per line, validated (outer rectangle, rectangular faces, no empty lines, size caps); local knot vectors read off rays from each vertex, rays leaving the mesh repeat the boundary (Sederberg et al. 2003 section 3) - rational T-spline evaluation and first derivatives for odd bi-degree, with a complete (p-1)/2-line frame and the domain inside it - T-junction extensions and the analysis-suitability check (Scott et al. 2012 section 2) - local refinement that keeps the surface exactly: requested knot lines are cut in, then every original blending function is carried as a record and split (violation 1) or the mesh gains edges (violations 2 and 3) until each record is a blending function of the refined mesh (Sederberg et al. 2004 section 3); analysis-suitable input stays analysis-suitable by carrying conflicting T-junctions across faces - NURBS <-> T-spline conversion for meshes without T-junctions, and Bezier extraction over the rectangles no blending-function knot line crosses Measured: regular T-spline vs NURBS < 1e-12, round trip exact, partition of unity with T-junctions < 1e-14, refinement deviation <= 1.4e-14 over 40 random refinements, Bezier patches vs surface < 1e-14. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01J53sR6gEaVt56soFDpTck8 * Convert T-splines to sewn NURBS sheet bodies in the kernel A T-spline is only useful to the modeller once it is a B-rep face set. tspline_sheet builds an open shell: a mesh without T-junctions becomes one clamped NURBS face; otherwise each Bezier element is a face, and sides are split at the T-points where neighbours' corners land, so all faces share vertices and edges and the sheet is one oriented shell (V - E + F = 1). Every truck call runs under guard. No command yet; Boundary Fill will be the first caller. Tests: one face for a regular surface, sewn Bezier faces with T-junctions, tessellated points on the surface to ~1e-9 mm, and hostile control nets (coincident, 1e300, needle-thin) never panic. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01J53sR6gEaVt56soFDpTck8 --------- Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
17 lines
367 B
TOML
17 lines
367 B
TOML
[package]
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name = "solvecraft-geom"
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description = "SolidCraft geometry foundation: vectors, planes, frames, meshes and their measures"
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version.workspace = true
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edition.workspace = true
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license.workspace = true
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[lints]
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workspace = true
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[dependencies]
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serde = { workspace = true }
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thiserror = { workspace = true }
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[dev-dependencies]
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serde_json = { workspace = true }
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