On a belt the parts print in belt order, so every colour change between parts
is a filament change. Arrange packs items in extruder order already, but it
grew the pile around its centre, so the colours ended up interleaved. A belt
print now packs from the leading end of the bed, each row filling across the
belt before the pile advances, and the objective charges an item for every
packed part of another colour it does not fully follow along the belt,
counting the tilted layers that reach cot(angle) * height past a part, so
each colour prints as one run. The direction follows the slicing rotation: a
rotation about X prints toward +Y, one about Y toward -X, and a negative angle
flips it. Packing from the edge also means the brim has to be kept on the
bed: a belt brim is printed brim_width wide for every brim type, so that much
is reserved along every edge (between parts the brims may overlap, as on any
printer).
The purge prism is regenerated from the arranged parts, flush with the far
edge of the bed, yet arrange moved it about like a part and packed parts into
the strip it comes back to. Arrange now skips the prism and reserves its strip
with a fixed virtual item, like a bed exclusion area, whenever the parts use
more than one filament.
The prism's length follows the parts plus a ramp per unit of height; with the
height at its cap that ran 100 mm past the end of a 500 mm belt and the project
could not print. The bar now stops at the plate end, and the purge planner's
existing warning reports what the shortened bar cannot absorb.
With best_object_pos away from the bed centre the placer packs the pile
inside the bin and then translates it so its centre lands on that point,
without checking that it still fits there. A belt printer aims at the
leading end of the belt (BabyBelt Pro: 0.5, 0.05), so any pile longer than
the 50 mm around that point was pushed past the edge: four 90 mm parts on
the 95 x 500 mm belt ended with one across the edge and one outside while
290 mm of belt stayed free.
The final alignment now stops the pile at the edge of the bin; the items'
inflated boxes leave the object spacing as the margin. A pile that does not
fit along an axis is centred on it, as before.
* fix(libnest2d): skip the excluded-region alignment pass when there are none
NfpPlacer::finalAlign(), run from clearItems() and the destructor, always
ran the "find a best position inside the NFP of fixed items" pass even when
no items are fixed. With nothing to avoid, calcnfp() computes the inner-fit
NFP of the pile and can feed clipper a coordinate outside its allowed range.
On Linux/clang the value stays in range so it went unnoticed; on MSVC the
clipper "Coordinate outside allowed range" exception escapes the noexcept
destructor and aborts the process (exit 0xC0000409).
Build the excluded set up front and only run the pass when it is non-empty.
The block exists solely to keep the pile clear of fixed items (excluded
regions / wipe tower), so it is a no-op when there are none and the
wipe-tower behaviour is unchanged.
* test(libnest2d): remove dead nesting tests and split the suite by feature
Seven of the suite's hidden [.] test cases drove code paths Orca abandoned
at the BambuStudio fork: BottomLeftPlacer (used nowhere in src/) and the
stock default NfpPlacer backend, which returns zero bins in Orca. They have
been red since the fork and are never registered with ctest. Remove them.
Split the 1,000-line libnest2d_tests_main.cpp into per-feature files, per the
repo convention, sharing a header for the no-fit-polygon backend setup that
every translation unit must agree on (ODR):
libnest2d_tests.cpp Item and nest() basics
test_geometry.cpp geometry primitives
test_nfp.cpp no-fit-polygon machinery
libnest2d_test_utils.hpp shared includes and the NFP backend specialisation
Along the way: drop a debug exportSVG() helper that only wrote a file on test
failure (so the suite never leaves stray assets), convert the deprecated
Catch::Approx to WithinRel/WithinAbs matchers, and give the tests descriptive
names.
* test(libnest2d): add NfpPlacer unit tests
NfpPlacer is the placement engine the arranger drives, but the suite only
covered the geometry primitives. Add a fixture and five tests that exercise
pack()/accept() directly: a single item lands in the bin, an oversized item
is rejected, the first item is seeded for every starting point, many items
pack without overlap, and the rotation candidates are searched. This lifts
nfpplacer.hpp line coverage from 42% to 87% in the libnest2d suite.
* test(libslic3r): add arrangement::arrange() integration coverage
The libnest2d suite cannot reach Orca's real nesting entry point because it
does not link libslic3r. Add test_arrange.cpp driving arrangement::arrange():
items land on the bed and within bounds, do not overlap, are spaced by their
inflation, an oversized item stays unplaced, overflow spills onto virtual beds,
an empty input is a no-op, and the DONT_ALIGN and USER_DEFINED final-alignment
paths are exercised. A self-test guards the overlap check the other cases use.
harrierpigeon