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Determines whether areas, surfaces, and solids are convex or concave. A polygon is simple when it is not self-intersecting and has a non-zero area. Simple polygons are convex if every internal angle is less than or equal to 180 degrees. All other polygons are considered concave.

Input Ports

Output Ports

If the geometry of the feature is polygon-based (such as a polygon, a donut, or a box) all of the geometry’s composing polygons are tested for convexity. Based on the results of this testing, the appropriate output port is determined.


There are no parameters for this transformer.

Usage Notes

  • Lines and points are considered concave.
  • The test is limited by the precision of the geometry’s coordinates – be careful of “invisible” bends in lines, as shown here:


This diagram shows both convex and concave examples.

FME Licensing Level

FME Professional Edition and above

Editing Transformer Parameters

Using a set of menu options, transformer parameters can be assigned by referencing other elements in the workspace. More advanced functions, such as an advanced editor and an arithmetic editor, are also available in some transformers. To access a menu of these options, click beside the applicable parameter. For more information, see Transformer Parameter Menu Options.

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Tags Keywords: convex concave "polygon based" "internal angle"