Sheet Metal Tab

Status: Implemented (Rust-kernel-backed)

Sheet Metal Tab starts a sheet-metal body from a closed sketch or face profile. Every other sheet-metal feature builds on a body it creates.

Inputs

• id – string, default null. Optional identifier for the history entry.
• profile – single reference_selection (FACE or SKETCH, default null). Closed sketch or face used to derive the root flat.
• thickness – number, default 1. Global sheet thickness for the model tree; it must be positive.
• placementMode – options, default forward: forward, reverse, or midplane placement relative to the profile plane.
• bendRadius – number, default 0.125. Default inside bend radius stored for downstream flange/hem features.
• neutralFactor – number, default 0.5. Default k-factor stored for downstream bend allowance (0–1).

There is no consumeProfileSketch switch: a sketch profile is always consumed on success. A FACE profile has nothing to consume and is left alone.

Behavior

• The profile becomes the root flat of the body, extruded by thickness. The flat pattern (Unfold, flat-pattern export) comes from the same model.
• Each outline edge gets a selectable side face, which is what Flange and Hem pick.
• The outer loop is oriented counterclockwise in the profile's local plane. A clockwise loop is reversed, including each curve's direction. Edges are named <id>:e0, <id>:e1, and so on in that resulting order. A loop with fewer than three segments is split at curve midpoints until it has at least three; these resulting segments determine the edge names.
• A flat's <flat-id>:A face points along its positive normal, and <flat-id>:B points in the opposite direction. These names apply to the root tab and to child flats created by flanges.
• The sheet-metal model travels with the body, not with the feature: every downstream sheet-metal feature reads it off the body it targets.

Walkthrough

Recorded from the running app by BREP_mcp/tests/videos/sheet-metal-tab.json; regenerate every walkthrough with ./build.sh docs-videos.

SM Tab is the feature that seeds a sheet-metal tree, so it is the one with no sheet to start from. Its profile is a closed sketch — and a sketch has no display mesh, so it cannot be clicked in the 3D view. The walkthrough picks it where a sketch is published: its row in the Scene panel.

The closing volume is the whole feature's arithmetic: 60 × 40 mm of outline at 2 mm gauge is 4800 mm³.