ajandClaude Opus 5.5
ffa3590b46
Priority was sorted descending, the reverse of the host (StockLadder and NestJobCandidateComparer treat a lower number as more important), so a priority-9 part beat a priority-0 part for scarce stock. The existing test encoded the inverted rule and now asserts the host's direction. Part geometry filtered only rapids, so scribe/etch moves counted as material - the bug OpenNest fixed in 1b5e1b1. Use SpecialLayers.IsMaterial. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
126 lines
8.9 KiB
Markdown
126 lines
8.9 KiB
Markdown
# OpenNest.Engine.Gpt6Astra
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An independent, deterministic .NET 8 CNC nesting plugin. Its public parameterless
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`Gpt6AstraNestingEngine` implements `INestingEngine`. The project remains outside `OpenNest.sln`.
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## Placement algorithm
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Gpt6Astra searches configuration space: for each stationary/moving orientation pair, a no-fit
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polygon describes the translations that would overlap. Subtracting these regions from the
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sheet's usable translation rectangle exposes contact positions where another part can fit.
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This permits overlapping bounding rectangles, complementary triangle pairs, staggered circles,
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concave interlocking, and insertion into straight-edged and curved holes.
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1. Validate immutable job input. Reconstruct owned analytic entities with `DrawingJobMapper`
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and `ConvertProgram`. Closed contours define material; internal open marks do not become
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holes. Preserve the snapshot's origin when converting normalized placements back to poses.
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2. Prepare rotated outlines and material regions with holes, using conservative curve flattening.
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Automatic angles combine 15-degree samples over a full turn with orientations aligned to the
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longest straight edges. Symmetric duplicates are removed. Prefer up to 16 orientations whose
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envelope area is within 8% of the minimum; retain additional orientations when needed to fit
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a candidate stock. Fixed and bounded rotation policies remain enforced. Bounded sweeps use
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up to 721 integer step indices, including permitted half-turn equivalents.
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3. Process high-priority parts first (a lower `Priority` number ranks higher, as in the host),
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then parts fitting fewer available stock types, then larger envelopes. Larger frames precede inserts. Search every retained orientation for each instance.
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4. Build cached Minkowski/no-fit regions. Convex pairs use Core's linear convex NFP primitive;
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concave pairs use Clipper's integer Minkowski sum. Arc-heavy concave contact outlines use
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a coarser mesh with both approximation bounds added to clearance; fine material geometry
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still checks every candidate. Positive outer boundaries are filled conservatively.
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Axis-aligned rectangles have a four-vertex contact shortcut.
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5. Maintain each orientation's available translation region incrementally as parts are added.
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Search its boundary vertices, exact-fit contacts and hole anchors. Reject points inside solid
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no-fit regions before expensive checks. Check surviving candidates against actual material
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regions with holes and spacing offsets. Zero-clearance contacts also pass the shared triangulated
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collision check, with tiny position adjustments when rounding makes an exact contact unsafe.
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Hole contacts use the same check in the final sheet coordinate frame, with bounded caching.
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Two directional objectives try bottom-up and left-to-right growth using the same contact algorithm.
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6. Search stock plans with a beam of up to three states. Rank by observed delivery cost and
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remaining material, while preserving a state with high placed area. This avoids starving
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large-sheet plans in favor of cheap but inefficient small-sheet prefixes. A genuine material
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area lower bound prunes plans only once a complete cheaper plan exists. After 24 evaluated
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trials only one directional objective is used; after 64, beam width reduces to two.
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Work counts, not elapsed time or randomness, control search breadth.
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7. Select a complete plan with lowest purchased area, breaking equal-cost ties by sheet count.
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If no complete plan is found, maximize fulfilled counts by priority, then minimize cost.
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Emit committed-sheet progress, contiguous per-part instance indices, inventory, fulfillment
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and the contract's job-level stop reason. Cancellation throws without returning a partial job.
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The engine never invokes another engine, registry, job runner, whole-plate nester or filler.
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All order, stock, orientation, placement, search and stopping decisions belong to Gpt6Astra.
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Core geometry and Clipper are primitives, not alternative nesters. A shared Core collision fix
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corrects curved-hole validation; the placement algorithm remains entirely in Gpt6Astra.
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## Precision and safety
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Analytic rotated bounds govern sheet containment. Material curves are conservatively flattened
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at 0.001 job units. Positive configuration-space spacing includes 0.0003 extra units for non-rectangular
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straight outlines; curved outlines reserve 0.003 extra units even at zero spacing, accounting for offset/chord error and the
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benchmark validator's four-decimal grid. Axis-aligned rectangle contacts preserve exact requested
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spacing. Actual material intersection checks backstop candidate construction. Both straight-edged
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and curved holes are available for insertion. The shared collision routine now subtracts hole
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triangles into disjoint fragments with consistent half-space clipping, resolving the reproduced
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curved-hole false positive. See the benchmark report for regression results.
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Concave contact outlines exceeding 64 vertices use a chord tolerance of the greater of 0.002
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units or 0.2% of the smaller envelope dimension. The pair's two tolerances are added to the
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NFP offset. This reduces Minkowski input size without coarsening the final material checks.
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The broad phase is deliberately conservative. It can miss a valid close fit; output validation
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is exercised separately through the benchmark's materialized geometry validator in tests.
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## Structure
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- `Gpt6AstraNestingEngine.cs`: bounded stock-plan search, accounting, progress and result construction.
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- `PreparedGeometry.cs`: snapshots, allowed orientations, symmetry reduction and material regions.
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- `ContactGeometry.cs`: cached no-fit polygons and rectangle specialization.
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- `ContactPlacer.cs`: incremental available regions, contact/inside-hole search and collision checks.
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- `tests/`: xUnit tests plus a linked copy of the existing benchmark validator source.
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- `benchmarks/`: standalone synthetic benchmark driver, reproducible repository-DXF manifests,
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baseline/current CSV results and comparison notes. It is not compiled into the plugin.
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`OpenNest.Engine.Gpt6Astra.csproj` references Core explicitly and inherits Engine/net8.0 settings from
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`../Directory.Build.props`. Test and benchmark sources are excluded from the plugin assembly.
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## Build, test and deploy
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```bash
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dotnet build OpenNest.Engine.Gpt6Astra/OpenNest.Engine.Gpt6Astra.csproj -c Release
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dotnet test OpenNest.Engine.Gpt6Astra/tests/OpenNest.Engine.Gpt6Astra.Tests.csproj -c Release
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dotnet build OpenNest.Benchmark/OpenNest.Benchmark.csproj -c Release
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mkdir -p ../OpenNest/OpenNest.Benchmark/bin/Release/net8.0/Engines
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cp OpenNest.Engine.Gpt6Astra/bin/Release/net8.0/OpenNest.Engine.Gpt6Astra.dll ../OpenNest/OpenNest.Benchmark/bin/Release/net8.0/Engines/
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dotnet ../OpenNest/OpenNest.Benchmark/bin/Release/net8.0/OpenNest.Benchmark.dll OpenNest.Engine.Gpt6Astra/benchmarks/dxf --engines Gpt6AstraNestingEngine --parallel 1
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```
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The host supplies Core, Engine and their dependencies. Plugin discovery uses the CLR type name
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`Gpt6AstraNestingEngine`; no registry call exists in the plugin.
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Rebuild the host with this checkout's `OpenNest.Core` as well: replacing only the plugin DLL
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does not update the shared curved-hole collision fix.
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## Limitations
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This is bounded heuristic search, not a proof of minimum sheet cost or infeasibility. Early part
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order is not backtracked within a sheet, already placed parts are not moved, and available
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orientations are sampled/pruned. Hole search uses anchor positions, not a complete inner-fit
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polygon solver. Small usable regions inside complex cutouts may be missed. The benchmark report
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includes an isolated host-validator reproducer and its corrected outcomes.
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Filling NFP interior voids can exclude unusual interlocking configurations.
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Salvage-credit options and `PlacementStrategy` do not change Gpt6Astra's objective; `MaxPlates` is
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respected. Stock dimensions, all edge spacings, quadrants, priorities and rotation policies are
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honored. No real `.nest` fixtures were available in this workspace.
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Complex concave outlines, dense bounded sweeps, many part types or very large quantities can
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be expensive. NFP and trial cache entry counts are bounded, but individual geometry can be large.
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Cancellation is checked throughout search and between geometry operations; shared validation and
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individual Clipper calls are not interruptible. The v2 search costs more CPU than the original
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bounding-rectangle baseline. See `benchmarks/README.md` for measured tradeoffs.
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## Current validation
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Release build succeeded with .NET SDK 8.0.425 on Linux. All 27 xUnit cases passed, including
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independent benchmark validation of materialized results, exact positive/zero clearance,
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non-cardinal rotations, hole insertion, automatic diagonal-only stock fits, all quadrants,
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curves, incremental geometry, determinism, inventory, cancellation and stock-plan regressions.
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All 34 synthetic/generated benchmark cases and all four repository-DXF cases were valid and complete.
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Existing nullable warnings originate from the benchmark validator linked into the test project.
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