Hi, Andrii, Below I upload the files for both Primal and Dual Voronoi graphs. I also modified the property maps and checked they work correctly. A simple way to use/test the graphs and the properties is as follows: I also realized that Middle Axis algorithms present some challenge here. Voronoi diagram does not keep its input and knows almost nothing about it. To discriminate "inner" and "outer" parts of polygons we should make some assumptions about the structure of input segments. One convenient way to do so is to pass some "polygon model" to future Middle-Axis functor. This model can be one of the concepts from Boost.Geometry (ring, polygon, multi-polygon). These models correspond to Boost.Polygon concepts of Polygon, Polygon_With_Holes and Polygon_Set, respectfully. (The library Boost.Geometry actually provides adapters for major Boost.Polygon concepts). Still, the functor can get into troubles when comparing the input vertices for equality. Comparing the input coordinates is not guaranteed to be robust; however, comparing input indexing can also get into trouble, e.g. when hole vertex coincides with external boundary vertex. Probably, one needs to provide several policies and traits of the Middle-Axis functor and let user decide on trade-offs. Thank you, -Michael BoostVoronoiPrimalGraph.hpp http://boost.2283326.n4.nabble.com/file/n4653800/BoostVoronoiPrimalGraph.hpp BoostVoronoiDualGraph.hpp http://boost.2283326.n4.nabble.com/file/n4653800/BoostVoronoiDualGraph.hpp -- View this message in context: http://boost.2283326.n4.nabble.com/Re-voronoi-medial-axis-tp4653498p4653800.... Sent from the Boost - Dev mailing list archive at Nabble.com.