Bambuddy's archive cards were blank for every print sliced through the
BS or Orca docker sidecars. The "Some recent prints couldn't be archived
with thumbnails" banner pointed at install step 4 which is unrelated —
that flag only fires on FTP-fetch failures, not on missing-thumb in the
sliced 3MF.
Root cause is upstream of Bambuddy: neither slicer CLI renders
Metadata/plate_N.png when invoked headlessly with --slice --export-3mf.
That render is a separate code path triggered by --export-png, which is
mutually exclusive with --export-3mf and additionally needs a working
display backend (BS 02.07.x's bundled GLFW is hard-locked to Wayland —
even XDG_SESSION_TYPE=x11 + GDK_BACKEND=x11 + QT_QPA_PLATFORM=xcb don't
switch it back). An Xvfb display in the sidecar wouldn't help even if we
wired the second-pass call. The Orca sidecar has been silently shipping
thumbnail-less 3MFs from STL inputs since launch; nobody noticed.
Fill the gap on the Bambuddy side: new plate_thumbnail.py renders the
missing thumbnails after the slice returns. inject_plate_thumbnails_if_missing
parses the sliced zip, finds every Metadata/plate_N.gcode entry that
doesn't have a matching plate_N.png, loads 3D/3dmodel.model via trimesh,
renders an isometric Bambu-green-on-dark view at 512x512 + 128x128 via
the same matplotlib Agg pipeline as stl_thumbnail.py, and re-packs the
zip with the PNGs injected. Visual style matches Bambuddy's existing
library thumbnails — archive cards stay consistent inside Bambuddy rather
than chasing parity with desktop Studio's plate render. Best-effort:
input bytes are returned unchanged on any failure so the slice flow itself
can never fail because of a missing thumbnail. Idempotent: re-running on
an already-injected 3MF returns the input verbatim.
Wired into both library.py slice paths via result._replace; covers the
cross-class merged-multi-plate path automatically (merged bytes flow into
the same write site). No sidecar Dockerfile change required — an earlier
attempt to install Xvfb in Dockerfile.bambu-studio was a false start and
is not part of this drop.
Dependencies: trimesh's 3MF loader uses networkx (scene-graph traversal)
and lxml (model.xml parse) lazily inside the 3MF code path — both added
to requirements.txt because they aren't strict trimesh transitives.
maziggy
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