ocp-gordon 0.1.15

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

Gordon Surface Library for CadQuery's OCP

This library provides a Python implementation for creating Gordon surfaces, 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.

The implementation is written entirely in Python and is adapted 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.

pip install ocp_gordon

Dependencies

• OCP (OpenCASCADE Python)
• NumPy
• SciPy

Usage

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

# Assume you have profile_curves and guide_curves defined as lists of B-spline objects
# profile_curves = [...] # List of Geom_BSplineCurve objects
# guide_curves = [...]   # List of Geom_BSplineCurve objects

from ocp_gordon import interpolate_curve_network

gordon_surface = interpolate_curve_network(profile_curves, guide_curves, tolerance=3e-4)

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

Test

To run tests, first install pytest, then:

python -m pytest

Notable Difference from C++ Code

• In intersect_bsplines.py, the math_BFGS method is polyfilled and used in place of math_FRPR, as neither math_BFGS nor math_FRPR is usable in OCP due to the lack of math_Vector exposure. The intersect detection algorithm has been improved for both speed and reliability.
• In the _solve() function of bspline_approx_interp.py, regularization has been added to prevent singular matrix issues, which can occur in cases such as when the input curve is a B-spline derived from a circle.
• A new file, misc.py, has been introduced to implement missing OCP utilities. The primary additions include clone_bspline and math_BFGS.
• Modified curve_network_sorter.py, bspline_algorithms.py, and interpolate_curve_network.py to allow a single point to be used as either a profile or a guide.

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}
}