Comparison with other libraries

These pages run the same tasks in planex2d, in OpenCASCADE (the netgen-occt build, used through netgen.occ) and in four polygon libraries: shapely (GEOS), pyclipper (Clipper), gdstk and manifold3d (Clipper2). OpenCASCADE is the kernel that planex2d passes its results to, and both keep lines, arcs and splines exact. The polygon libraries work with straight edges only, so round shapes reach them as polygons. The method:

• the polygons are shapely buffers, tessellated finely enough that the area agrees with the exact planex2d area to about 10⁻⁷, and all four polygon libraries get the same polygons;

• the polygons are converted for each library before the clock starts, and only the Boolean operation is timed;

• the times are the best of three runs, and for OpenCASCADE of one run;

• as on the landing page, the three libraries built on Clipper share one bar, which shows the fastest of them;

• the code is comparison_libraries.py in the docs folder.

The timings are measured every time the documentation is built, on the machine that builds it:

import platform
print(platform.processor() or platform.machine(), "Python", platform.python_version())

x86_64 Python 3.12.15

• Union of many discs
• Union of traces
• Merging split edges
• Nearly coincident edges
• Gluing many faces