added preserve thin geometry to helpcenter (#25)

Author: wiktor-flex

docs/02.simulation-setup/02.mesh/01.mesh.md

@@ -17,6 +17,7 @@ The Meshing Defaults define the baseline mesh generation parameters that control
 | **Boundary layer first layer thickness** | First layer thickness for volumetric anisotropic layers |
 | **Refinement factor** | Global scaling factor for mesh refinement |
 | **Gap treatment strength** | Controls mesh behavior in narrow gaps |
+| **Preserve thin geometry** | Specifies whether thin geometry features should be resolved accurately during surface meshing|
 
 ---
 
@@ -111,6 +112,16 @@ The Meshing Defaults define the baseline mesh generation parameters that control
 >  - Critical for mesh quality in tight geometric spaces
 >  - Helps prevent highly skewed elements in narrow regions
 
+#### **Preserve thin geometry**
+
+*Flag to specify whether thin geometry features should be resolved accurately during the surface meshing process.*
+
+- **Default:** `False`
+>**Notes:**
+>  - This setting is only effective when using Geometry AI.
+>  - Resolves features with thickness roughly equal to `geometry_accuracy`.
+>  - Can be overridden using **GeometryRefinement**.
+
 ---
 
 <details>
@@ -191,6 +202,7 @@ meshing_defaults = fl.MeshingDefaults(
     curvature_resolution_angle=12 * u.deg,
     boundary_layer_growth_rate=1.2,
     boundary_layer_first_layer_thickness=0.01 * u.mm,
+    preserve_thin_geometry=True
 ) 
 ```
 </details>

docs/02.simulation-setup/02.mesh/03.refinements/07.geometry-refinement.md

@@ -9,6 +9,7 @@
 | *Option* | *Description* |
 |------------|-----------------|
 | **Geometry accuracy** | The smallest length scale to be accurately resolved by the surface mesher. |
+| **Preserve thin geometry** | Specifies whether to accurately resolve thin geometry features. |
 | **Assigned surfaces** | The surfaces to which the refinement is applied. |
 
 ---
@@ -26,6 +27,14 @@
 > - A smaller `Geometry accuracy` value will result in a finer mesh and consequently a larger cell count and longer computation time.
 > - Start with a larger value and decrease it iteratively to find the optimal balance between accuracy and computational cost.
 
+### **Preserve thin geometry**
+
+*Specifies whether thin geometry features should be accurately resolved during surface meshing.*
+
+- **Default:** `false`
+> **Notes:**
+> - Resolves features with thickness roughly equal to `geometry_accuracy`.
+
 ### **Assigned surfaces**
 
 *The list of surfaces where the geometry refinement will be applied.*
@@ -68,7 +77,8 @@ import flow360 as fl
 geometry_refinement = fl.GeometryRefinement(
     name="fine_features_refinement",
     faces=[geometry["wing_surface"], geometry["fuselage_surface"]],
-    geometry_accuracy=0.001 * fl.u.m
+    geometry_accuracy=0.001 * fl.u.m,
+    preserve_thin_geometry=True
 )
 ```
 </details>

docs/02.simulation-setup/02.mesh/03.refinements/README.md

@@ -137,7 +137,8 @@ meshing=MeshingParams(
         fl.GeometryRefinement(
             name="fine_features_refinement",
             faces=[wing_surface, fuselage_surface],
-            geometry_accuracy=0.001 * fl.u.m
+            geometry_accuracy=0.001 * fl.u.m,
+            preserve_thin_geometry=True
         )
     ]
 )

docs/02.simulation-setup/02.mesh/README.md

@@ -23,12 +23,13 @@ A section for defining the meshing settings.
 
 ### **[Refinements](./03.refinements/README.md)**
 
-*Comprehensive local mesh control system for critical regions. Provides six refinement types.*
+*Comprehensive local mesh control system for critical regions. Provides seven refinement types.*
 
 **Subsections:**
 - **[Surface Edge Refinement](./03.refinements/01.surface-edge-refinement.md)** - Controls mesh resolution near edges
 - **[Surface Refinement](./03.refinements/02.surface-refinement.md)** - Controls surface mesh cell size
 - **[Boundary Layer Refinement](./03.refinements/03.boundary-layer-refinement.md)** - Creates prismatic layers near walls
 - **[Passive Spacing](./03.refinements/04.passive-spacing.md)** - Controls mesh behavior without direct refinement
 - **[Uniform Refinement](./03.refinements/05.uniform-refinement.md)** - Creates uniform mesh spacing in a region
-- **[Axisymmetric Refinement](./03.refinements/06.axisymmetric-refinement.md)** - Creates structured-like mesh with cylindrical bias
+- **[Axisymmetric Refinement](./03.refinements/06.axisymmetric-refinement.md)** - Creates structured-like mesh with cylindrical bias
+- **[Geometry Refinement](./03.refinements/07.geometry-refinement.md)** - Controls mesh resolution based on geometric features