The bundled hex_cell.scad has many more knobs than the dozen we used to
expose (box clearances, cap/box wall, vertical stacking, busbar template,
etc). Maintaining a hand-curated PARAMS list in Python next to a SCAD file
that already documents every variable inline was always going to drift.
Sync + auto-extract approach:
- scad/hex_cell.scad: replace with the upstream master file from
Albert Phan's Hex-Cell-Holder fork (adds the BUSBAR TEMPLATE section
and the "busbar template" part option).
- holder.py: PARAMS now built at import time by _scan_scad(), which
regexes top-level `name = literal; // help` lines into Param entries
up until the // END OF CONFIGURATION marker. Scan handles bool /
number / string literals; derived expressions and helper variables
are skipped automatically.
- Manual maps stay small and explicit: _SELECT_OPTIONS for the few
string-enum params (part, pack_style, box_style, template_outline,
template_hole_style, etc.), _GROUP_RULES for UI sectioning, and
_NUMBER_HINTS for sensible min/max/step on the most-tweaked numbers.
UI:
- holder-app.js: extra GROUP_ORDER / GROUP_LABELS for the new
sections (cap, box, insulator, bolts, wires, stacking, template,
advanced). Group titles are now click-to-collapse; the advanced
groups start collapsed so the form isn't a wall of inputs on load.
- holder.css: caret marker on the group title, smooth rotate on
collapse, hides the body via .collapsed class.
Net effect: every variable in the .scad — including the new busbar
template knobs — is editable from the page, with helpful comments
copied straight from the .scad source.
The hex_cell.scad echoes its computed dimensions (pack_height_holder,
total_*_holder, box_total_*) to stderr. Capture those and surface them
in the viewer so the user can sanity-check whether the assembled
battery will fit in a target case.
Backend:
- holder.py: render_stl() now returns (stl_bytes, dims) where dims is
a {name: float} dict parsed from openscad ECHO lines.
- app.py: /api/holder/render emits the dims dict as an
X-Holder-Dimensions response header (JSON) with the matching
Access-Control-Expose-Headers entry so fetch() can read it under
any proxy / future CORS setup.
Viewer (holder-viewer.js):
- New setGhostBox(name, {w,d,h}, {visible,color}) and clearGhostBox(name)
helpers. Each ghost is a Group of a translucent BoxGeometry mesh +
matching EdgesGeometry wireframe, positioned to match how the STL
mesh is placed (centred XY, bottom on Z=0).
UI (holder.html / holder.css):
- New "Fit check" panel under Status with two sections:
• Show max bounding box (auto, from ECHO — defaults to box_total_*
dims, falls back to total_*_holder + pack_height_holder).
• Show enclosure (manual W × D × H inputs in mm).
- Verdict line under the enclosure inputs: "✓ fits" green or
"✗ too small — battery won't fit" red.
Controller (holder-app.js):
- Reads X-Holder-Dimensions after each render, updates the max-box
ghost in blue, prints the dimensions label.
- Watches enclosure inputs + toggles, drives the enclosure ghost
(green if it fits, red if smaller than the max box on any axis).
- Fit comparison is orientation-independent in the XY plane (sorted
W,D pair) but strict on Z (height).
User-triggered 120x120 = 14400 cells, which produces huge STL/long
renders. Total cells is the right metric (CSG cost scales with count,
not max axis), so cap by N = rows*cols (or rows*(rows+1)/2 for tria
style). 1000 covers any realistic pack (e.g. 20x50) while blocking
accidental misuse.
Backend:
- holder.py: MAX_CELLS env-tunable (default 1000); expected_cell_count
and _check_cell_limit raise ValueError on exceed; both
compute_cells() and render_stl() call it up-front.
- app.py: /api/holder/render now returns 400 on ValueError (not 500)
so the frontend can distinguish bad input from server failure.
/api/holder/params now publishes max_cells alongside the schema.
Frontend:
- holder-app.js: reads max_cells from the params endpoint; status
shows "N cells / over limit (1000)" in red and disables the
Render and "Design busbars" buttons when exceeded.
- holder.css: .topbar-status.over-limit style (red, bold).
- Replace debounced auto-render-on-param-change with an explicit Render
button. Param changes mark the button "dirty" (accent ring); user clicks
Render to drive a render. A Cancel button (AbortController) appears
while a render is in flight.
- Add indeterminate progress bar with elapsed-time counter in the status
panel. Real OpenSCAD --progress streaming can come later.
- Bump OPENSCAD_TIMEOUT default 60s -> 300s and gunicorn --timeout
120s -> 300s. The 60s cap was misclassified by the frontend as
"OpenSCAD not installed" because the error string contained the word
"openscad" -- which the JS matched too greedily.
- Frontend error classifier now distinguishes "binary not found",
"timed out", and "geometry empty" cases and only shows the
install-OpenSCAD hint for the real not-found case.
Server-side OpenSCAD renders STL from bundled hex_cell.scad with parameter
overrides via -D. Frontend is a Three.js viewer with auto-form generated
from /api/holder/params. 'Design busbars →' button posts the computed
cell coordinates to /api/projects and redirects to the busbar editor with
the holder cells pre-loaded.
- holder.py: openscad subprocess wrapper + compute_cells()
(Python mirror of get_hex_center_points_*)
- scad/hex_cell.scad: verbatim copy of Addy/Hex-Cell-Holder source
- app.py: /holder route + /api/holder/{params,render,cells}
- static/holder.html etc: parameter form + Three.js STL viewer
- Dockerfile / install.sh: apt install openscad
- static/index.html: nav link Holder ↔ Busbars in topbar
Web tool for designing nickel/copper busbars over cylindrical-cell battery
packs (21700, 18650) in hex holders. Flask + build123d backend exports
STEP/DXF/SVG; vanilla JS frontend with live preview, multi-project SQLite
persistence, snapshot history.
Deploy scripts in deploy/ (proxmox-lxc.sh, install.sh, update.sh).
wenil