ocp-gordon 0.1.0

A Python library for Gordon Surface interpolation using B-splines.

Gordon Surface Library

This library provides a Python implementation for creating Gordon surfaces, which are a method for interpolating a network of curves to generate a smooth surface. It is designed to be compatible with CadQuery's OCP and leverages B-spline mathematics.

It is a line by line translation from the original C++ code in occ_gordon

Features

• Gordon surface interpolation from profile and guide curves.
• Compatibility with B-spline representations.
• Integration with CadQuery's OCP (OpenCASCADE Python) for geometric primitives.

Installation

This package can be installed using pip. It is recommended to use a virtual environment.

pip install ocp_gordon

Dependencies

• OCP (OpenCASCADE Python)
• NumPy
• SciPy

Usage

Here's a basic example of how to use the library:

# This is a placeholder example. Actual usage may vary based on the library's API.
from ocp_gordon import interpolate_curve_network

# Assume you have profile_curves and guide_curves defined as lists of B-spline objects

# Example:
# profile_curves = [...] # List of Geom_BSplineCurve objects
# guide_curves = [...]   # List of Geom_BSplineCurve objects

try:
    gordon_surface: Geom_BSplineSurface = interpolate_curve_network(profile_curves, guide_curves)
    # You can then use gordon_surface with CadQuery or other visualization tools
    print("Gordon surface created successfully.")
except Exception as e:
    print(f"An error occurred: {e}")

For more detailed examples, please refer to the examples/ directory in the source code.

Test

To run tests, first install pytest, then:

cd tests
python test_all.py

Notable Difference from C++ Code

• A major difference is that in intersect_bsplines.py, a polyfilled math_BFGS is used instead of math_FRPR because both math_BFGS and math_FRPR are not usable in OCP because OCP does not implement math_Vector. The activate() function in this file has also been changed since the original one does not work well.
• In the _solve() function in bspline_approx_interp.py, the regularization is added to prevent singular matrix which occurs in some cases for example when the input curve is a bspline converted from a circle.
• A new file misc.py is added to implement some missing classes/functions from OCP. The major ones are clone_bspline and math_BFGS.

License

This project is licensed under the Apache 2.0 License - see the LICENSE file for details.

Citing

The algorithm was originally described in:

Siggel M. et. al. (2019), TiGL: An Open Source Computational Geometry Library for Parametric Aircraft Design

@article{siggel2019tigl,
	title={TiGL: an open source computational geometry library for parametric aircraft design},
	author={Siggel, Martin and Kleinert, Jan and Stollenwerk, Tobias and Maierl, Reinhold},
	journal={Mathematics in Computer Science},
	volume={13},
	number={3},
	pages={367--389},
	year={2019},
	publisher={Springer},
    doi={10.1007/s11786-019-00401-y}
}