Making polygons created by Concave Hull algorithm contiguous

Question

I have a set of points grouped and enclosed by a Concave Hull polygon as in this question. Within an outer boundary that encloses all the polygons I would like to make these polygons contiguous, that is individual polygons should expand so that each polygon shares edges with its neighbours or the enclosing boundary. Is this possible? I am using QGIS.

This what the original polygons look like:

This is an approximation of what I want, the rules are that the number of polygons should stay the same and that all points that originally were in a particular polygon, should remain within the altered version of that polygon.

Kadir's original solution works well but left a couple of artefacts.

The updated answer resolves this problem.

Answer 1

• First, use one of Densify tools (Densify by interval or Densify by count) suitable for you to add additional vertices on polygons' edges.
• Extract the vertices to points using Extract vertices tool.
• Create Voronoi polygons using these points. (Voronoi polygons tool) > Layer_A
• Add a field (POL_ID as an example) to Voronoi polygons (Layer_A) to indicate intersecting Concave Hull. (Join attribute by location tool) > Layer_B
• Use Dissolve tool to combine polygons in Layer_B by POL_ID.