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Brushbuilders are tools which forge the red builder brush into basic shapes. They are the 3rd group of buttons in the UnrealEd toolbox. Coders that want to understand or make new ones should see the class definition of BrushBuilder.

Brushbuilders interface

To apply the shape to the red builder brush, either:

  • Click a button to forge the red builder brush with the default shape and dimensions.
  • Right-click a button to open the floating Brushbuilder parameters window.


Numeric parameters accept a mathematical expression, for example "=64+128" or "=4*(256+128)".

Operator Description
* Multiplication
/ Division
+ Addition
- Subtraction
() Grouping, for example: =(128+64)/2= yields 96

Parameters with a mini drop-down menu (true/false and enumerations) can be advanced to the next option by double-clicking the parameter name or the value box.

Each brushbuilder remembers its own parameters throughout the UnrealEd session

If shapes seem distorted or rotated, check the red builder brush for brush transformation; do transform permanently to quickly cure this.

Default Builders


Creates cubes and box shapes in general.

Default: 256x256x256 cube


Creates cylinders

Default: 8 sided cylinder, 256 height, 512 radius.


Builds an approximation of a sphere. Tears the BSP to shreds, so use sparingly.

Spiral Stairs

These can't be used as a subtractive brush, as they leave sheet polys between each step. Use the alternative TarquinSpiralStairBuilder from the Tarquin Brushbuilders pack instead.


Creates a tesselated cube for use in creating terrain. This is a leftover from UnrealEd 2; realistic terrain is now made separately. In pre-UT2003 versions, it is recommended to use an external terrain generator or 3D Studio Max to create pleasing, more realistic terrain. See Making Terrain (UT).



Creates rectangular sheet brushes, used to make glass, zone portals etc. For more complex shapes, use the 2D Shape Editor.


Creates a cone.

Curved Stairs

Creates a curved staircase.

Linear Stairs

Creates a standard staircase.


Makes a collection of sheets forming a star. Ideal for chains and fire: it's recommended to set NumSheets to 2 for chains and 3 for fire. Since these are sheets, intersecting while the red builder brush is in this shape has unexpected results. See VolumetricBuilder.

Custom BrushBuilders

UnrealEd also support plug-in brushbuilders. See the list at Custom Brushbuilder, Custom Brushbuilder Ideas and scripting custom Brushbuilders for details on how to create them.

Related Topics


Birelli: I like the new format Tarq. I think it helps those of us who have no concept of basic shapes to figure out what's what (j/k). The only thing I think should be changed is the spacing of the columns, the two sides' entries would look better if they all matched up horizontally. I'm not sure how to achieve this though, maybe it's not possible with the wiki markup as it stands :-\.

Tarquin: tx :). can't do the spacing thing though, as there's no rowspan in wiki tables.

Mychaeel: What about splitting the image in its individual rows? Then you could even line the descriptions up with their respective button rows.

Flashman: Has anyone done one of these for UED 3.0? the differences are subtle, but having the new stuff on the same page moght be confusing. /me volunteers to make the new one

Tarquin: Just update above, if the differences are very small.

Sobiwan: Since this page is named as the plural version BrushBuilder, I suggest we rename this to using brushbuilders to clarify this page's intent

Tarquin: harder to link to. If you really think we should have a clear difference, I'd say Template:Brushbuilder tools. Look at how this page is linked from Category:Legacy Basic Procedure pages.

lazy oli when i want to add a sphere to the room, it usually doesn't work. players fall through some of the triangles while

others seem to be solid. sort of a noob question but does anybody have an idea why?

Wormbo: It's called BSP holes.

lazy oli Thanks.