bherbruckandClaude Opus 5.5
45bc22fc30
A profile traced over a face sketch's projected boundary left the extrude's caps and sides without an exact planar source, so a sketch or offset plane on the new top face was refused. The drawn curve is now the edge's source where it covers a projection. Clearer fixed-plane message; regression tests in the engine, UI harness and design corpus, plus a corpus-wide flat-face attachment check (known gaps under #491-#495). Fixes #489 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
78 lines
5.2 KiB
Markdown
78 lines
5.2 KiB
Markdown
# Face-attached sketches
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New face-attached sketches store the selected source body, its creating feature, an exact
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face certificate, and the source and author occurrence paths. The sketch's picked origin
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and orientation are stored in the source face's canonical plane. Editing the source height
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or moving its placement therefore updates the sketch plane while preserving its local
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geometry and dimensions.
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Supported planar sources are exact Box faces, untapered New Body and Join Extrude caps and
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straight sketch sides, and planar faces of immutable STEP imports. Extrude caps also identify their
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outer boundary and holes by source curve IDs. Reordering profiles cannot substitute another
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profile's cap. A profile drawn over a face sketch's projected boundary (a rectangle
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traced over the whole face, or a strip whose sides lie on the face's edges) is identified by
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the drawn curves: where a drawn curve and a projected one cover the same edge, the drawn curve
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is the source. Two drawn curves, or two projections, over one edge remain ambiguous. Curved surfaces cannot host a planar sketch through this workflow.
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Edited surfaces without retained construction provenance, ambiguous sources, and unsupported
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generators require an explicit fixed plane instead. A face that a Join merged from two features' coplanar
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faces belongs to neither, so it also needs a fixed plane. The error says why, and the Create
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Sketch dialog then offers **Use fixed plane**, which places the sketch on that face's current
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plane without following later changes. A nearby or parallel face is never used
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to repair a new attachment automatically.
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The flat faces of a sheet metal body are the exception: they have no construction
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certificate, so a sketch on one attaches to its panel by name (`sheet:<body>:<panel>:<side>`)
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and finds it again after every rebuild, unfold and refold. If that panel no longer exists the
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sketch reports a lost attachment, as above. See the sheet metal guide.
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## Create and repair
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Select a supported planar face and create a sketch. The desktop selection supplies the exact
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body and face index, including its occurrence path. Command callers can use
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`sketch.create` with `plane: {face: [x,y,z], body: "world body key", index: face_index}`;
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the point is in world coordinates. A point-only face request must find a unique supported
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source. An unsupported or ambiguous request fails with an explanation instead of creating
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an attachment with weaker identity.
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When a source is suppressed, deleted, replaced, or loses its certificate, the sketch reports
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a lost attachment. Its saved plane is only a visible repair guide: it does not produce a
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healthy solved sketch or let downstream features build at a substitute face.
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Use **Redefine Sketch Plane** to select a new supported face explicitly. The draft can be
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reviewed before applying it; cancellation leaves the existing attachment intact. Reattachment
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keeps existing sketch geometry, IDs, and dimensions. When the selected source changes, its
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previous automatically projected boundary becomes ordinary geometry on the new plane;
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it is not replaced by a newly projected boundary. Rebinding to the same certified source
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retains its live boundary. Manually created projection links retain their own sources.
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Choose an explicit fixed plane to detach the sketch. This preserves its current local
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geometry and dimensions and converts only its automatically projected face boundary to
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ordinary geometry. Manual projection links remain attached to their own sources. A fresh
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fixed-plane sketch has no live face auto-projection.
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## Occurrences, pending positions, and files
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The selected source occurrence and the sketch's author occurrence are separate identities.
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Repeated instances therefore cannot silently switch an attachment to the first placement.
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A missing author path also requires explicit repair. Reattachment and creation capture
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pending positions only on the involved source and author paths. Failed commands restore
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those pending positions; undo restores the previous attachment and placement state.
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File format 11 introduced these optional attachments, which format 12 also preserves. Existing designs with face references
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without an attachment retain their legacy geometry and lookup behavior when opened; they
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are not silently upgraded. Redefining such a sketch onto a supported selected face creates
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the stronger attachment. Unsupported legacy geometry can instead be retained on an explicit
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fixed plane. Imported attachments also bind the exact STEP payload digest, item entity, and
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face entity: replacing the payload cannot reuse an old attachment merely because a face
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index or shape looks the same.
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## Profiles generated by face modelling commands
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Extrude, Revolve, and Press Pull can generate an internal sketch from a selected planar face. Supported
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sources use the same certified attachment and live boundary as an ordinary attached sketch.
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For modified faces without a construction certificate, these commands retain their historical
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named-face and linked-boundary behaviour through a private compatibility path. Initial capture
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uses the selected body and face index. These helper sketches do not have the stronger saved
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identity guarantee of a certified attachment. This compatibility path does not change the
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requirements for creating an ordinary face-attached sketch.
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