Add wave overhang support

[bsx1990]

Summary

• Add wave overhang toolpath generation for unsupported cantilevered overhang regions.
• Add print settings, preset persistence, GUI controls, and English/Chinese translations.
• Emit tagged G-code paths with wave-overhang flow and speed overrides.
• Add regression coverage for generation, configuration handling, slicing stability, and perimeter ordering.

Why

Wave overhangs provide a supportless way to print cantilevered overhangs by propagating wave-shaped paths from supported regions. This can reduce support material and post-processing for suitable geometries while keeping a preserved outer perimeter for dimensional stability.

Implementation Notes

• The algorithm follows the behavior of the PrusaSlicer and OrcaSlicer wave-overhang forks, adapted to Bambu Studio's perimeter and configuration structures.
• Wave paths are prepended ahead of preserved outer walls in the affected island so the overhang support is printed before the final boundary wall.
• The default preserves one outer perimeter and replaces only the overhang-region interior with wave paths.
• Debug G-code markers are available to inspect generated wave-overhang paths.

Testing

• git diff --check $(git merge-base HEAD origin/master)..HEAD
• libslic3r_wave_overhangs_tests "[WaveOverhangs]" passed locally before PR cleanup.
• Built Bambu Studio locally on macOS before PR cleanup.
• Sliced the provided 3MF test model with wave overhangs enabled.
• Verified slicing no longer throws runtime errors such as std::bad_cast for the tested model.
• Verified wave paths are emitted before preserved outer walls in the tested overhang layer.

References

• https://waveoverhangs.com/
• https://github.com/stmcculloch/PrusaSlicer-WaveOverhangs
• https://github.com/dennisklappe/OrcaSlicer-WaveOverhangs

[bsx1990]

Additional screenshots

These screenshots show the current wave overhang test result, slicer preview, and Chinese settings panel.

Printed sample in the printer	Printed wave-overhang surface detail
Printed side view	Slicer preview
Chinese wave-overhang settings panel

[ArthurBambulab]

Must address before merge

1. Hidden dependency on detect_overhang_wall

Wave generation requires both wave_overhangs and detect_overhang_wall (PerimeterGenerator.cpp, classic + Arachne). Enabling wave overhangs alone produces no paths with no UI feedback.

→ Document in tooltip, warn in GUI, or auto-enable / recommend detect_overhang_wall.

2. wave_overhang_outer_perimeters > 1 does not match implementation

should_replace_with_wave_path() only preserves erExternalPerimeter. Paths have no perimeter index, so values > 1 do not keep extra outer walls—only affects expand_wave_overhang_target_area().

→ Clamp UI to 0..1, or implement real multi-wall keep + update tooltip.

3. wave_overhang_debug_gcode defaults to true

;WAVE_OVERHANG_START/END in G-code by default bloats output and complicates tooling for an experimental feature.

→ Default false; opt-in for debugging.

4. Silent failure when prepending wave paths

prepend_wave_overhang_paths_to_last_island() fails silently on dynamic_cast miss—paths computed but not inserted.

→ Add debug log or debug-build assert when wave paths are non-empty but insertion fails.

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Strongly recommended

5. Sub-options lack enable_if

All wave-overhang fields stay editable when wave_overhangs is off.

→ Grey out / hide dependents on master toggle (and corner-taper fields on wave_overhang_corner_taper_enable).

6. Duplicated PerimeterGenerator integration

Same logic at ~1619 (classic) and ~2031 (Arachne).

→ Extract shared helper, e.g. try_generate_and_prepend_wave_overhangs(...).

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Additional comments

7. Default wave_overhang_print_speed = 2 mm/s may be too slow

2 mm/s feels unusably slow vs typical wall speeds. What speed was used for the PR test prints? Was 2 mm/s a safe universal default?

→ Consider 10–20 mm/s default or preset-specific values; add tooltip/PR note with tested speeds.

Suggested experiments on the same test model (PLA / 0.4 mm nozzle):

Parameter	Try	Observe
wave_overhang_print_speed	5, 10, 15, 20, 30 mm/s	Curl, adhesion, surface
wave_overhang_line_spacing	0.25, 0.35, 0.45 mm	Sag vs density
wave_overhang_flow_mm3_per_mm	±10%	Under/over-extrusion
wave_overhang_outer_perimeters	0 vs 1	Accuracy vs overhang quality

8. Dedicated “Wave overhangs” page — move under Support

A full new tab is heavy for an experimental feature.

→ Remove standalone page; add options under Support (e.g. “Wave overhangs (experimental)” group + collapsed Advanced). Keeps supportless-overhang tooling in one place.

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Summary

#	Topic	Severity
1	detect_overhang_wall dependency	Must fix / document
2	outer_perimeters > 1 semantics	Must fix / clamp
3	debug_gcode default true	Must fix
4	Silent prepend failure	Must fix
5	Missing enable_if	Strongly recommended
6	Duplicated perimeter logic	Strongly recommended
7	Default speed + experiments	Additional
8	UI under Support	Additional