sheet_unfold
Unfold a sheet-metal part into its flat cut blank and report every bend, including allowance, deduction and K-factor source. Build the flat solid for measuring, exporting or nesting.
Instructions
Develop a sheet part into its flat pattern — the blank the part is cut from — and report every bend.
The flat pattern is derived from the bend tree, not reverse-engineered out of the fused solid, so it is exact rather than fitted: each bend contributes its bend allowance BA = angle·(R + K·t), the arc length of the neutral fibre.
k_factor: pins K for every bend. bend_table: a shop's own measured rows [{thickness_mm, inner_radius_mm, angle_deg, allowance_mm | deduction_mm}] — a matching row OUTRANKS the chart, because the shop's press is the ground truth for the shop's press. Without either, K comes from a press-brake corpus keyed by material and r/t. WHICHEVER IT IS, IT IS ECHOED BACK per bend as k_factor + k_source: a flat length whose K you cannot see is a number you cannot check.
build: also create the flat blank as a real solid (holes included) at origin
in the XY plane, so it can be measured, exported or nested.
Fidelity: 'exact' only when EVERY bend's K was supplied or table-derived — BA
given K is pure arithmetic. One corpus-defaulted bend makes the development a
'correlation' with band_pct, and developed_band_mm gives the resulting
millimetre spread of the blank across that K band.
Returns {ok, handle?, name?, volume?, outline, holes, bend_lines, bends,
regions, flat_size, flat_bbox, flat_area_mm2, blank_area_mm2,
blank_volume_mm3, thickness, material, fidelity, band_pct, developed_band_mm,
warnings} — regions being each flat region's polygon, which is what lets the
whole report be handed straight back to sheet_refold. Each
bend row carries angle_deg, direction, inner_radius_mm, leg_tangent_mm,
outer_length_mm, bend_allowance_mm, bend_deduction_mm, outside_setback_mm,
k_factor, k_source, and the bend_line / tangent_start / tangent_end segments in
flat coordinates. ok=False means the blank cannot be cut as drawn — two feature
footprints overlap — with warnings naming which.
Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| name | No | SheetFlat | |
| build | No | ||
| handle | Yes | ||
| origin | No | ||
| k_factor | No | ||
| bend_table | No |