Clipper2GH / Clipper2 comparisons

[dwydd_nu (Dwydd)]

So I’ve started to make some benchmark comparisons between the two after this

Clipper2 offset bug and solution

I was in need of a very efficient and robust tool for curve offsetting. The best solution I found was Clipper2GH by seghier, which unfortunately is no longer mantained, the author allegedly had himself deleted from this forum. I ran into an apparent bug which creates “spikes” of line segments between offset and original lines. I tried all my knowledge to spot the possible cause outside the component itself (cleaning, culling, rebuilding) but the bug really seems coming from Clipper2GH. I also t…

The first impressions are.. “it’s a hell, guys”

1. Minkowski sum/difference: Clipper2GH is clearly 6.3x faster. It has an option to keep open curves open, which the other has not. But mirrors the curves around XY plane (?). Clipper does not show this bug, and apparently there is no difference between Sum and Displaced Sum

2. Minkowski sum of an imitation of Wikipedia’s example:

Clipper2GH: it doesn’t automatically convert and accept the given Degree2 curves, they need to be explicitly converted. The sum is “in place” meaning that it phisically represents the envelope of one shape moved about the path. Clipper: it automatically accepts the given curves doing an implicit conversion, the result is out of place, like in Wikipedia’s example. Perhaps mathematically correct, but not so much intuitive and of practical use as is. Again no difference between the two results.

As said before, each has many differences, pro/cons, and bugs. This confirms my idea that still today there is no unique best implementation of Clipper and it is a shame.