Legacy:Merge Polygons

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A set of coplanar polygons in a brush can be merged together. Merged polygons are treated as single surface in UnrealEd which makes texture alignment easier. Nodes are always convex, so the result may still be made up of several nodes. Effects of this procedure:

  • polycount is reduced
  • node count may be reduced. This depends on the shape and configuration of the polygons you are merging. If it's possible to merge adjacent polygons while preserving conmvexity, the engine will do so.
  • the brush wireframe is unchanged.

This can be used on any type of brush, add / subtract, any solidity.

If you are using subtracted trim then it pays to optimise your brush.

To merge polygons:

  1. Select them (see selecting surfaces)
  2. Align them with either the 'align to wall' or 'align to floor' command in the surface properties window.
  3. Select the brush they belong to by SHIFT + left-clicking a surface. It doesn't matter if the surfaces become unselected.
  4. Do: Brush Context Menu -> Polygons -> Merge
  5. rebuild geometry
  6. each sets surfaces on the brush which are coplanar and aligned will now behave as a single surface.


  • the brush's wireframe will not change.
  • polygons do not need to be adjacent to be merged
  • polygons need to be in the same alignment to be merged, but the panning does not need to be seamless.

Related Topics

Tutorials that use this technique (brief list)