cadSet/docs/cad-feature-tree.md

CAD Feature Tree Export

feature_tree.json is now a SolidWorks FeatureManager-style export. Semantic models are replayed from the feature nodes themselves; uploaded STEP models use a SolidWorks-style imported feature with an embedded SurfaceIR payload.

Contract

• The artifact name stays feature_tree.json.
• tree_kind is solidworks_feature_manager.
• schema_version is 1.0.
• The JSON Schema lives at designir-pipeline/contracts/feature_tree.schema.json.
• Studio records the artifact with role feature_tree; no feature-tree UI is required.

Top-level fields are:

• model: part metadata such as model id, family, units, and document type.
• source: DesignIR path, STEP path, reconstruction mode, backend, and the native-history claim.
• feature_manager: root id, standard SolidWorks reference nodes, and ordered feature nodes.
• rebuild_contract: the replay mode and compiler entrypoint.
• validation: structure validation, replay status, geometry/B-Rep status, and feature-recognition coverage.

FeatureManager Style

Every tree starts with a familiar part root and reference geometry:

• 历史
• 原点
• 前视基准面
• 上视基准面
• 右视基准面
• 原点

Semantic DesignIR features are normalized into SolidWorks-style nodes:

• extrude_circle, extrude_rectangle, add_cylinder -> BossExtrude
• through_hole -> CutExtrude
• polar_hole_pattern -> seed CutExtrude plus CircularPattern
• recognized future operations map to Revolve, RevolvedCut, HoleWizard, Fillet, Chamfer, LinearPattern, and MirrorPattern

Parameters are attached to the owning feature node. They are not top-level tree nodes. Each parameter keeps a binding_id that matches parameters.json and the DesignIR semantic parameter name.

Semantic feature trees do not embed a full DesignIR copy. BossExtrude, CutExtrude, and CircularPattern nodes store the reconstructable sketch, depth, direction, hole, and pattern definitions needed by the FeatureTreeCompiler.

Each node also includes SolidWorks-style inspection fields:

• definition: feature-specific definition such as end condition, depth, direction, merge result, seed features, axis, or sketch profile.
• dimensions: SolidWorks-style dimension rows such as D1@凸台-拉伸1, with parameter bindings when available.
• references: sketch, plane, parent features, and child features.
• selection_sets: selected faces, edges, and contours. These stay empty until stable B-Rep selectors are available.
• rebuild: suppression and rollback/rebuild status.

STEP And SurfaceIR

STEP does not contain original SolidWorks sketches or FeatureManager history. For uploaded STEP/SurfaceIR models, the exporter creates one canonical SolidWorks-style imported feature:

• solidworks_type: ImportedFeature
• display_name: 导入1
• english_name: Imported1

The imported feature embeds compressed gzip+base64+json SurfaceIR. This keeps the tree honest and independently replayable without pretending that the original native CAD history was recovered.

Replay

The tree can be replayed without sibling files:

python designir-pipeline/scripts/feature_tree.py compile \
  feature_tree.json \
  --output-step replayed.step \
  --output-designir replayed.designir.json

Semantic trees replay through feature_tree.compile_feature_manager, which builds DesignIR 3.0 from FeatureManager nodes and then calls designir_pipeline.compile_designir. Imported SurfaceIR trees replay through surfaceir_pipeline.build_surfaceir.