The Vortek rack holds six hotends, and a multi-colour plate is sliced to
use a different one per colour so it can skip the purge. Which of the six
each colour takes is not in the 3MF. The same plate, sliced and sent twice
from Bambu Studio with a different choice each time, produces two files
that differ only in rounding in the last digit of a few extrusion figures
-- the filament grouping, the toolchange stream, the 120 nozzle-change
markers and project_settings.config are all identical. The choice travels
only in the dispatched nozzle_mapping.
Bambuddy had no way to state it, so those plates went out with no nozzle
assignment at all and the printer chose for itself. That is what levelled
on one hotend and printed with another, millimetres above the plate.
Every rack-bound filament now carries a position picker beside its AMS
slot dropdown, listing all six with the nozzle each holds. An empty
position, or one holding the wrong diameter or flow type, is shown greyed
out with the reason rather than hidden, so someone looking for position 4
finds it. The choice is per filament *group* rather than per slot, because
a group is one hotend: two filaments the slicer grouped together share it
and cannot point at different positions.
Nothing has to be picked. Positions are assigned automatically, preferring
one already loaded with that colour, which on the plate this was built
against reproduces Bambu Studio's own pick exactly.
A nozzle currently picked up onto the carriage is offered too. The
firmware drops its rack position from the report entirely rather than
sending a placeholder (#943), and refusing it would rule out the position
most likely to be wanted -- the one the last print left mounted. Only
recoverable when exactly one position is missing; two gaps are genuinely
ambiguous and stay unavailable.
Positions are re-checked at dispatch, not just when queued, because the
rack can be re-loaded in between. The two failure modes differ on purpose:
an explicitly chosen position that no longer fits stops the print, names
what the position now holds, and deletes the uploaded file from the SD
card so it cannot be started by hand either -- an operator who named a
hotend must not silently get a different one. An automatic assignment that
cannot be made instead falls back to letting the firmware choose, which is
what happened before any of this existed.
The pick is stored as {group: position} rather than as the expanded
nozzle_mapping, though that is what goes on the wire. That column means
"Bambu Studio decided, forward verbatim", and only the group-and-position
form can be re-checked against what is actually mounted at dispatch.
The existing multi-rack refusal in extract_nozzle_mapping_from_3mf stays.
It still guards the #2800 fallback, which can only ever name one rack id.
Measured on the maintainer's H2C: rack position n is physical nozzle id
15 + n, confirmed by cross-referencing two captured dispatches against
Bambu Studio's own dialog. extruder_max_nozzle_count names which carriage
is the rack straight from the file, and is read rather than assumed -- a
fourth independent confirmation of the carriage indices fixed in 45dc139.
The print dialog is also wider, on every printer. Its filament rows carry
the most horizontal content in it and adding a picker truncated names to
"Bamb...". The column widths themselves only change on a rack machine.
Tests: 44 unit covering the plan, the resolver, the mounted-nozzle
recovery and every refusal; 9 dispatch integration asserting the two real
captures end to end; 7 API round-trip; 33 frontend. The API ones exist
because two integration bugs got through a green suite that tested the
pieces and not the seams -- the group data reached only one of the three
filament-requirements routes, and the field was declared on every schema
except the create one, where Pydantic dropped it in silence.
The print uploaded, the printer took the command, and stopped at once with
HMS 0500-4047 -- "the available hotend quantity or model does not match the
sliced file". nozzle_mapping told the printer one of the plate's filaments
went to no hotend while ams_mapping named the tray it comes from, and the
firmware will not start a job on that contradiction.
Each filament in a 3MF names the group it belongs to, and on every other
dual-nozzle Bambu the group number is also the extruder index, so it was
read as one. On a rack machine it is not: the rack carriage holds six
hotends to the fixed carriage's one, so the slicer writes a group per
nozzle rather than per carriage. The failing plate carried groups 0, 1 and
2 against a two-entry physical_extruder_map, and the filament in group 2
was dropped -- indistinguishable downstream from a slot the plate does not
print, which is what reached the wire as -1.
extract_nozzle_mapping_from_3mf now resolves the group through the table
the file states for itself, the <nozzle id extruder_id> elements in
slice_info.config. Files carrying no such table keep the direct index, so
H2D slices are unaffected. A filament that still cannot be placed drops
the whole mapping with a logged reason instead of half an answer: the
firmware then picks its own nozzle, which is the pre-existing behaviour
and far better than an answer that contradicts itself.
Two related faults fixed in the same pass. The mapping was read across
every plate in the file, so on a multi-plate project a slot took its
extruder from whichever plate came last; it is now scoped to the plate
being dispatched, in extract_filament_requirements as well. And the array
is now one entry per filament slot, matching BambuStudio's own dispatch of
[1, 16, 16] for a three-filament plate, rather than padded to a fixed 32.
Verified against the file that failed: slot extruders [-1, 1, 0] became
[0, 1, 0], and the wire [-1, 16, 1, -1 x29] became [1, 16, 1].
Queueing several plates of one 3MF built a single filament-override list from
every selected plate and posted that same list with each plate's item. A
force_color_match entry blocks dispatch until the printer has that exact colour
loaded, so a single-colour plate waited on the whole batch's palette. The same
shared list also widened required_filament_types, making a PLA plate refuse
every printer that lacked a sibling plate's PETG.
Narrow the overrides to the slots the plate actually consumes, on create and on
update -- in the backend, where the 3MF is, so it holds for every writer of the
queue. Dispatch already re-parsed requirements per plate and keyed overrides by
slot, so the dropped entries were inert there. When the plate's slots cannot be
read the overrides are kept whole: an item waiting on a colour it does not need
is visible, one that silently lost a forced colour prints in the wrong filament.
Items queued before this would stay stuck with a waiting reason that explains
nothing, so a startup migration re-scopes the pending ones. Printing and
finished items keep their overrides -- that is a record of what they dispatched
with, not an instruction.
Edward's diagnosis was exact: the manual /print-queue/ POST extracts
filament requirements from the 3MF and writes
required_filament_types + filament_overrides + ams_mapping onto the
queue item, but the VP queue-mode write path skipped all of that.
Net effect: scheduler reached its model-only-matching fallback and
auto-dispatched onto whatever printer was free regardless of loaded
colour.
Extract the scheduler's existing _get_filament_requirements 3MF
parser into a shared helper so the VP path can reuse it. VP's
_add_to_print_queue now populates required_filament_types
unconditionally (cheap; helps the scheduler reject obvious type
mismatches) and writes filament_overrides with force_color_match:
true per consumed slot when a new per-VP queue_force_color_match
toggle is on. Default off to preserve current behaviour for
upgraders.
UI: new toggle on VirtualPrinterCard, mode-gated to print_queue,
mirroring the existing auto-dispatch toggle. i18n: en + de
translated, other 6 locales seeded with English copy.
Schema: one nullable column on virtual_printers
(queue_force_color_match BOOLEAN, default 0/FALSE).
11 new backend tests (8 for the extracted parser, 3 for the VP
write path) + 6 new frontend tests (toggle render gating, default
state, click posts queue_force_color_match in update body).
Existing scheduler tests pass against the refactored helper.
README, CHANGELOG, website features page, and wiki virtual-printer
page all updated.
maziggy