Optimal Label Point (Pole of Inaccessibility) for Any Planar Polygon

Grasshopper
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1

Hi everyone!

I am excited to announce a new addition to Bowerbird: the BB Label Point component (BBLabelPt), located under the Text subcategory.

If you’ve ever tried to place text labels inside arbitrary planar shapes, you know that using the standard geometric centroid can be problematic. For concave shapes (like L-shapes or U-shapes), the centroid often falls completely outside the polygon. For polygons with holes, the centroid might end up inside an empty cutout.

BB Label Point solves this by calculating the pole of inaccessibility. This is the point furthest away from any boundary or hole (i.e., the center of the largest possible inscribed circle).

Key Features:

  • Guaranteed optimal placement: The point is guaranteed to be placed in the area with the most space, even inside highly concave shapes.
  • Automatic hole detection: Automatically detects and avoids holes, finding the best spot in the remaining solid area.

The component integrates PolylabelNet, a fast C# port of Mapbox’s Polylabel algorithm, and Clipper2 for classifying outer boundaries and inner holes regardless of their winding direction.

Here are some examples:

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image1636×1122 177 KB

The current version of Bowerbird (v2.10) containing this new component can be downloaded directly inside the Rhino Package Manager.

2

hello
cool to see you back, as I have now a laser cutter (wood and metal) I just reuse Bowerbird yesterday. But I think it lacks a functionality, I wanted to make some waffle as support for holding my metal pieces for welding. If I am not wrong waffle section is just the intersection of the middle plane and the object.
As it was missing I did implement this tool in Nautilus but whatever it could be useful in Bowerbird. with 3 options

  • external (if you need to carve)
  • middle like it is actualy
  • internal (for example for holding sheets or adding some clay to make shapes).