Plot 2D Function

Plot 2D Function

File: Shape_Generation_Scripts/Plot_2D_Function.py
Version: 1.0
Document Type: Part

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Description

Evaluates a user-entered mathematical expression f(x) over a specified X range and creates the resulting curve in the active CATPart as a GSD point set and open spline. All functions from Python's math module are available in the expression (sin, cos, sqrt, log, exp, pi, e, etc.). The output plane selects which axes are used for the X and Y directions.

Settings are saved between sessions.

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Requirements

Requirement	Value
Python	>= 3.10
pycatia	>= 0.8.3
wxPython	Required
Open document	Part

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Usage

1. Open a CATPart document
2. Run the script
3. Enter the expression, X range, number of points, and output plane in the dialog
4. Click OK — the expression is validated then a progress bar shows while geometry is created
5. A new geometric set is added to the part containing the point set and open spline

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Parameters

Parameter	Description	Default
f(x) =	Python math expression using x as the variable	sin(x) * 10
X start	Start of the X range in mm	0.0
X end	End of the X range in mm. Must be greater than X start.	300.0
Points	Number of sample points. Minimum 2.	100
Plane	Output plane: XY, XZ, or YZ	XY

Expression Syntax

The expression is a Python math expression where x is the independent variable. Available functions:

Category	Functions
Trigonometric	sin, cos, tan, asin, acos, atan, atan2
Hyperbolic	sinh, cosh, tanh
Power / log	sqrt, exp, log, log2, log10
Rounding	floor, ceil, fabs
Constants	pi, e
Other	abs, round, factorial

Examples:

Expression	Curve
sin(x) * 10	Sine wave, amplitude 10 mm
x**2 / 100	Parabola
log(x + 1) * 20	Logarithm curve (x must stay > −1)
cos(x * pi / 180) * 50	Cosine where x is in degrees
sqrt(abs(x)) * 5	Square-root shape

The expression is evaluated at x = 1 during validation to catch syntax errors before touching CATIA.

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Dialog Buttons

Button	Action
OK	Validates expression and inputs, then generates the curve
Cancel	Exits without generating
Reset Defaults	Restores factory default values
Clear Saved	Deletes the saved user presets file
Help	Opens the full in-script user manual

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Output

A geometric set named f(x)_<expr> is created at the top level of the part tree containing:

f(x)_sin(x)x10
├── Points
│   ├── Pt_0001
│   ├── Pt_0002
│   │   ...
│   └── Pt_0100
└── Function_Spline  (open)

The spline is open (not closed). X and Y values are in mm.

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Plane Orientation

Plane	Horizontal axis	Vertical axis
XY	X	Y (f(x))
XZ	X	Z (f(x))
YZ	Y	Z (f(x))

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Settings Persistence

Settings are saved automatically to:

%APPDATA%\pycatia_scripts\Plot_2D_Function\user_presets.json

The next time the script runs, your last-used values are pre-filled in the dialog.

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Notes

• The expression must be defined and finite over the full X range — division by zero, log of a negative number, or other math errors will abort the script
• The geo set name is a sanitised version of the expression, truncated to 30 characters
• All point coordinates are in mm; the expression result is treated directly as mm