Add Z Contouring print settings docs (#225)

home.md

@@ -78,6 +78,7 @@ OrcaSlicer is a powerful open source slicer for FFF (FDM) 3D Printers. This wiki
 - [<img alt="param_seam" src="https://github.com/OrcaSlicer/OrcaSlicer/blob/main/resources/images/param_seam.svg?raw=true" height="22"> Seam Settings](quality_settings_seam)
 - [<img alt="param_precision" src="https://github.com/OrcaSlicer/OrcaSlicer/blob/main/resources/images/param_precision.svg?raw=true" height="22"> Precision](quality_settings_precision)
 - [<img alt="param_ironing" src="https://github.com/OrcaSlicer/OrcaSlicer/blob/main/resources/images/param_ironing.svg?raw=true" height="22"> Ironing](quality_settings_ironing)
+- [Z Contouring](quality_settings_z_contouring)
 - [<img alt="param_wall_generator" src="https://github.com/OrcaSlicer/OrcaSlicer/blob/main/resources/images/param_wall_generator.svg?raw=true" height="22"> Wall generator](quality_settings_wall_generator)
 - [<img alt="param_wall_surface" src="https://github.com/OrcaSlicer/OrcaSlicer/blob/main/resources/images/param_wall_surface.svg?raw=true" height="22"> Walls and surfaces](quality_settings_wall_and_surfaces)
 - [<img alt="param_bridge" src="https://github.com/OrcaSlicer/OrcaSlicer/blob/main/resources/images/param_bridge.svg?raw=true" height="22"> Bridging](quality_settings_bridging)

print_settings/quality/quality_settings_z_contouring.md

@@ -0,0 +1,46 @@
+# Z Contouring
+
+Z contouring, also called Z-layer anti-aliasing or ZAA, reduces visible stair-stepping on curved and sloped top surfaces by adjusting the Z height of individual extrusion points so the toolpath follows the original model surface more closely.
+
+![z-contouring](https://github.com/OrcaSlicer/OrcaSlicer_WIKI/blob/main/images/z-contouring/z-contouring.jpg?raw=true)
+
+Instead of keeping every move at a single flat Z for the whole layer, OrcaSlicer processes eligible top-surface toolpaths and emits varying Z values inside the affected layer.  
+This can noticeably smooth domes, chamfers, shallow slopes, and similar top-facing geometry without changing the nominal layer height of the rest of the print.
+
+> [!NOTE]
+> Current implementation targets top-facing curved or sloped surfaces.  
+> **Downward-facing or upside-down curves are not handled.**
+
+> [!IMPORTANT]
+> NEW FEATURE: **Z Contouring**  
+> Available in: [Nightly builds](https://github.com/OrcaSlicer/OrcaSlicer/releases/tag/nightly-builds) or Releases greater than **2.3.2**.
+
+- [Minimize wall height angle](#minimize-wall-height-angle)
+- [Minimum z height](#minimum-z-height)
+- [Don't alternate fill direction](#dont-alternate-fill-direction)
+
+## Minimize wall height angle
+
+[Mode](option_mode): `Expert`.  
+[Variable](built_in_placeholders_variables): `zaa_minimize_perimeter_height`.  
+Reduce the height of top-surface perimeters so they better match the model edge on shallow slopes.  
+This setting affects both internal and external perimeters.  
+Set `0` to disable it.
+
+Although 35 degrees is a reasonable starting point, the current implementation defaults to `0`, so this behavior is off unless you enable it explicitly.
+
+## Minimum z height
+
+[Mode](option_mode): `Expert`.  
+[Variable](built_in_placeholders_variables): `zaa_min_z`.  
+Minimum local layer height allowed for contoured toolpaths. This setting also controls the slicing plane used for contoured layers.
+
+- Lower values allow stronger contouring but leave less minimum layer thickness.
+- Higher values reduce the amount of contouring and keep the adjusted path closer to the nominal layer height.
+
+## Don't alternate fill direction
+
+[Mode](option_mode): `Expert`.  
+[Variable](built_in_placeholders_variables): `zaa_dont_alternate_fill_direction`.  
+Keep fill direction consistent from layer to layer on contoured layers instead of alternating it.  
+This can help produce a more consistent surface pattern on curved top surfaces. It only has an effect when Z contouring is enabled for that region.