Adds a way to print a busbar on a 3D printer to physically verify
sizing before laser-cutting nickel/copper. The existing "Extrude
solid + 0.2mm" path stays for thin-strip STEP — slicers can't print
0.2mm sheet — so the FDM path has its own thickness input (default
2mm, min 0.5mm).
Backend:
- busbar_export.py: new to_stl() writer. Forces extrude_flag = True
(STL is inherently 3D) and bumps thickness up to 2mm if the
incoming value is <0.5mm. Registers under WRITERS["stl"] so the
existing /api/export/<fmt> route serves it for free.
UI:
- index.html: new "FDM test print" block under the Params panel
with its own thickness input and two buttons (STL, STEP). The
existing 'Extrude solid' checkbox + 0.2mm thickness keep
driving plain "Export STEP".
- styles.css: .fdm-block / .fdm-row / .fdm-buttons styles
matching the existing panel typography.
- app.js: _exportFdm(fmt) reuses Exporter.exportFormat with a
shallow-merged params override ({extrude: true, thickness: fdmT}),
so the on-the-fly request gets the FDM settings without
mutating the live params state.
Verified: STL render of a 3-cell strip @ 2mm => 73KB binary STL
(opens cleanly in slicers); STEP @ 2mm => 160KB ISO-10303-21
solid; existing flat STEP path unchanged at 15KB.
wenil
7512393ef4