I am trying to implement a zoning system like the district tool in Cities Skylines (see screenshot below). The player is able to draw/modify/erase zones with a brush tool. Internally, I represent each zone with a closed chain of vertices equally spaced out. I am new to computer graphics and game dev in general. I appreciate any pointer! :-)

  1. How do I render the semi-transparent white overlay for each zone as in the screenshot? My current solution involves a dynamically generated mesh, with a semi-transparent material. Is there a better way?
  2. How do I render the white bold edge of each zone?
  3. How do I render the "sticki-ness" between the edges? As in, when two edges get too close, the game fills the tiny space between them with white color as well.

I'm using Unreal 5 if that matters.

enter image description here


1 Answer 1


I ended up applying an additive material on the dynamic polygon, such that I don't need to worry about the placement of the polygon and the weird glass-like refraction effect caused by semi-transparent material.


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