offset_polygon

compas.geometry.offset_polygon(polygon, distance, tol=None)[source]

Offset a polygon (closed) by a distance.

Parameters:

polygonsequence[point] | compas.geometry.Polygon: The XYZ coordinates of the corners of the polygon. The first and last coordinates must not be identical.
distancefloat | list[tuple[float, float]]: The offset distance as float. A single value determines a constant offset globally. A list of pairs of local offset values per line segment can be used to create variable offsets.
tolfloat, optional: A tolerance value for intersection calculations. Default is TOL.absolute.

Returns:

list[[float, float, float]]: The XYZ coordinates of the corners of the offset polygon. The first and last coordinates are identical.

See also

offset_polyline
offset_line

Notes

The offset direction is determined by the normal of the polygon. If the polygon is in the XY plane and the normal is along the positive Z axis, positive offset distances will result in an offset towards the inside of the polygon.

The algorithm works also for spatial polygons that do not perfectly fit a plane.

Examples

>>> from compas.geometry import Polygon
>>> polygon = Polygon([(0.0, 0.0), (1.0, 0.0), (1.0, 1.0), (0.0, 1.0)])
>>> offsetted_polygon = offset_polygon(polygon, 0.5)
>>> offsetted_polygon
[[0.5, 0.5, 0.0], [0.5, 0.5, 0.0], [0.5, 0.5, 0.0], [0.5, 0.5, 0.0]]