pygeo.clean_polygon_2d_ex

Cleans one or more 2D polygon loops and returns the cleaned result as loops.

This function is located in the pygeo module.

The function is intended for 2D polygon cleanup in the local u/v plane. The input format follows the loop structure of pytha.create_polygon_ex: each loop contains a point table and may optionally contain a segment table. Arc definitions are segmented internally before the cleanup step. The returned result contains only plain point loops.

pygeo.clean_polygon_2d_ex(
    {{loop_points_1, loop_segments_1} [,{loop_points_2, loop_segments_2} [,...]] }
    [, options]
)

Parameter	Type	Description
loop_points_i	{{u,v}, ...}	Coordinates of the loop points in 2D.
loop_segments_i	{segment_1, segment_2, ...}	Optional specification of the segments. Each segment may be a table with the following fields:
segment_i.angle	number	Angle of the arc, positive for counter-clockwise arcs.
segment_i.radius	number	Radius of the arc.
segment_i.orientation	"cw" or "ccw"	For radius specification: clockwise or counter-clockwise orientation.
segment_i.select_arc	"small", "large"	For radius specification: select the small or large arc.
segment_i.bulge	number	Maximum distance between the secant and the arc, positive for counter-clockwise arcs.
segment_i.segments	integer	Number of edge segments used for arc segmentation.
options	{...}	Optional: a table that may contain the following options:
options.minimum_winding	integer	Minimum winding number a region must reach to be kept in the result. Default 1. With 2, only regions covered by at least two loops remain, which corresponds to a boolean intersection of two polygons (each loop contributing winding 1).

Return value

Type	Description
loops	{{{u,v}, ...}, ...}

Notes:

• This is a purely 2D cleanup function. Input and output use u/v coordinates only.
• The input format is analogous to pytha.create_polygon_ex, but the function does not create geometry. It only cleans the loops and returns point coordinates.
• Segment definitions are resolved internally into point sequences before cleanup.
• The returned loops contain only point coordinates. Arc, radius, angle and bulge information is not preserved in the result.
• The result may contain multiple loops even if the input contains only one loop.
• The outer loop is returned in CCW orientation, inner loops in CW orientation.
• options.minimum_winding controls how overlapping loops are resolved: 1 (default) keeps every region inside any loop (union-like cleanup), while higher values keep only regions covered by at least that many windings. Passing two overlapping loops with minimum_winding = 2 therefore yields their boolean intersection.

Example:

Boolean intersection of two overlapping squares (the result is the shared region):

local intersection = pygeo.clean_polygon_2d_ex(
    {
        { {{0, 0}, {10, 0}, {10, 10}, {0, 10}} },   -- first square
        { {{5, 5}, {15, 5}, {15, 15}, {5, 15}} },   -- second square, overlapping
    },
    { minimum_winding = 2 }
)
-- intersection -> single loop around {5,5} .. {10,10}

Version Support:

Minimum PYTHA Version: V26

See also:

pygeo, pygeo.clean_polygon_2d, pytha.create_polygon_ex, pytha.create_polyline_ex