feat: Add Z Anti-Aliasing (ZAA) contouring support (updated) #354

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MrUnknownDE · 2026-04-05T16:20:12+02:00

MrUnknownDE commented

2026-04-05 16:20:12 +02:00

Originally created by @adob on 3/11/2026

This PR supersedes #12225, which originally proposed this feature but appears inactive.

The feature originated from work I developed earlier in BambuStudio-ZAA, a private fork of Bambu Studio

Compared to #12225, I updated the implementation for current upstream and fixed the following issues:

fixed broken tests
removed references to nonplanar directory

Reviewers may want to compare against #12225 for earlier discussion/context.

Summary

Port of Z Anti-Aliasing (ZAA) from BambuStudio-ZAA to OrcaSlicer.

ZAA eliminates visible stair-stepping on curved and sloped top surfaces by raycasting each extrusion point against the original 3D mesh and micro-adjusting its Z height to follow the actual surface geometry. The result is visibly smoother domes, chamfers, and shallow slopes — without post-processing.

How It Works

The slicer runs normally, then a posContouring step processes each layer
ContourZ.cpp raycasts every extrusion point vertically against the source mesh
Each point's Z is adjusted to the mesh intersection, converting flat Polyline paths into Polyline3 paths with per-point Z coordinates
The G-code writer emits the adjusted Z values, so the printer follows the true surface

Configuration

Five new settings under Print Settings > Quality:

Setting	Type	Default	Description
`zaa_enabled`	bool	off	Master enable/disable switch
`zaa_min_z`	float	0.06 mm	Minimum Z layer height; controls slicing plane offset
`zaa_minimize_perimeter_height`	float	35°	Reduce perimeter heights on slopes below this angle (0 = disabled)
`zaa_dont_alternate_fill_direction`	bool	off	Keep fill direction consistent instead of alternating
`zaa_region_disable`	bool	off	Disable ZAA for a specific print region/material

Key Changes

Core algorithm: New src/libslic3r/ContourZ.cpp (~330 lines) — raycasting engine
3D geometry: Point3, Line3, Polyline3, MultiPoint3 extend existing 2D types
Arc fitting: Templated to work with both 2D and 3D geometry
Pipeline: ExtrusionPath::polyline changed from Polyline to Polyline3; new posContouring step in PrintObject.cpp
G-code: GCode.cpp writes per-point Z when path.z_contoured is set
UI: ZAA settings exposed in Print Settings > Quality panel
Documentation: docs/ZAA.md with usage and implementation details

57 files changed, ~1800 insertions, ~200 deletions.

Test Plan

Load a model with curved top surfaces (sphere, dome, chamfered box)
Enable Z contouring in Print Settings > Quality
Slice and verify G-code has varying Z values within contoured layers
Build on macOS (verified), test on Linux and Windows

*Originally created by @adob on 3/11/2026* This PR supersedes #12225, which originally proposed this feature but appears inactive. The feature originated from work I developed earlier in [BambuStudio-ZAA](https://github.com/adob/BambuStudio-ZAA), a private fork of Bambu Studio Compared to #12225, I updated the implementation for current upstream and fixed the following issues: - fixed broken tests - removed references to nonplanar directory Reviewers may want to compare against #12225 for earlier discussion/context. ## Summary Port of **Z Anti-Aliasing (ZAA)** from [BambuStudio-ZAA](https://github.com/adob/BambuStudio-ZAA) to OrcaSlicer. ZAA eliminates visible stair-stepping on curved and sloped top surfaces by raycasting each extrusion point against the original 3D mesh and micro-adjusting its Z height to follow the actual surface geometry. The result is visibly smoother domes, chamfers, and shallow slopes — without post-processing. ## How It Works 1. The slicer runs normally, then a **posContouring** step processes each layer 2. `ContourZ.cpp` raycasts every extrusion point vertically against the source mesh 3. Each point's Z is adjusted to the mesh intersection, converting flat `Polyline` paths into `Polyline3` paths with per-point Z coordinates 4. The G-code writer emits the adjusted Z values, so the printer follows the true surface ## Configuration Five new settings under **Print Settings > Quality**: | Setting | Type | Default | Description | |---------|------|---------|-------------| | `zaa_enabled` | bool | off | Master enable/disable switch | | `zaa_min_z` | float | 0.06 mm | Minimum Z layer height; controls slicing plane offset | | `zaa_minimize_perimeter_height` | float | 35° | Reduce perimeter heights on slopes below this angle (0 = disabled) | | `zaa_dont_alternate_fill_direction` | bool | off | Keep fill direction consistent instead of alternating | | `zaa_region_disable` | bool | off | Disable ZAA for a specific print region/material | ## Key Changes - **Core algorithm**: New `src/libslic3r/ContourZ.cpp` (~330 lines) — raycasting engine - **3D geometry**: `Point3`, `Line3`, `Polyline3`, `MultiPoint3` extend existing 2D types - **Arc fitting**: Templated to work with both 2D and 3D geometry - **Pipeline**: `ExtrusionPath::polyline` changed from `Polyline` to `Polyline3`; new `posContouring` step in `PrintObject.cpp` - **G-code**: `GCode.cpp` writes per-point Z when `path.z_contoured` is set - **UI**: ZAA settings exposed in Print Settings > Quality panel - **Documentation**: `docs/ZAA.md` with usage and implementation details 57 files changed, ~1800 insertions, ~200 deletions. ## Test Plan - [ ] Load a model with curved top surfaces (sphere, dome, chamfered box) - [ ] Enable **Z contouring** in Print Settings > Quality - [ ] Slice and verify G-code has varying Z values within contoured layers - [ ] Build on macOS (verified), test on Linux and Windows

MrUnknownDE added the Community testers wanted Community testers wanted Community testers wanted Crazy Orca Community labels 2026-04-05 16:20:12 +02:00

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Reference: github/OrcaSlicer#354