File: Shape_Generation_Scripts/Custom_Coordinate_Airfoil_Generator.py
Version: 1.0
Document Type: Part

Creates a GSD point set and spline in the active CATPart from arbitrary X Y (or X Y Z) coordinates. Coordinates can be loaded from a .dat, .csv, or .txt file, or pasted directly into a text area in the dialog. Selig .dat format is supported — the airfoil name header line is automatically skipped.

The script creates a geometric set containing:

• A Points sub-set with all input points
• A GSD spline (Airfoil_Spline) through all points — open or closed at the user's option

The output plane (XY, XZ, YZ) and an optional chord scale are user-selectable. Plane and scale settings are persisted between runs.

1. Open a CATPart document
2. Run the script
3. Choose input mode (File or Paste Text) and supply your coordinates
4. Set the chord scale, close spline option, and output plane
5. Click OK — a progress bar shows while geometry is created
6. A new geometric set is added to the part containing the point set and spline

Click Browse to select a coordinate file. Supported formats:

Lines beginning with # are treated as comments and skipped. Any line that cannot be parsed as numbers is silently ignored.

Switch to Paste Text mode and type or paste coordinates directly into the text area. Each line should contain one point:

1.00000 0.00000
0.95063 0.00624
0.80003 0.01223
...

Columns may be separated by spaces, tabs, or commas.

When set to a positive value, the input coordinates are normalised to their X-range (max X − min X = 1) and scaled so the chord equals the specified length in mm.

Set to 0 to skip scaling and use the raw coordinate values as-is. This is the correct setting when coordinates are already in mm.

Connects the last point back to the first point to form a closed loop.

• Enable for complete airfoil profiles that list coordinates around the full contour (e.g. Selig .dat files running TE → upper → LE → lower → TE)
• Disable for open curves or when only one surface is provided

Determines which 3-D plane the 2-D (X Y) input is placed on:

If 3-column (X Y Z) input is supplied, this setting is ignored and coordinates are used directly.

A geometric set named Custom_Airfoil is created at the top level of the part tree containing:

Custom_Airfoil
├── Points
│ ├── Point_001
│ ├── Point_002
│ │ ...
│ └── Point_NNN
└── Airfoil_Spline (open or closed)

Plane, scale, and close-spline settings are saved automatically to:

%APPDATA%\pycatia_scripts\Custom_Coordinate_Airfoil_Generator\user_presets.json

The raw coordinate data is not saved.

• At least 3 valid coordinate pairs are required to create a spline
• The script handles mixed Selig .dat files where the header is a non-numeric string — it is silently skipped during parsing
• If 3-D (X Y Z) coordinates are detected in any row, the plane selection is ignored and all rows are treated as 3-D
• The geometric set is always named Custom_Airfoil; rename it in the CATIA tree after generation if needed