Legacy:Red Builder Brush
From Unreal Wiki, The Unreal Engine Documentation Site
In the beginning was the red builder brush. It looked around itself and found it was alone. Alone in a great patch of matter which dimensions could not be known.
The Active Brush is the basic tool of UnrealEd. It is displayed as a wireframe of dotted red lines, and hence is is commonly referred to as the Red Builder Brush, or RBB. There is only ever one RBB in a map. It is a grind with which you'll be able to subtract or add matter from the Unreal World and thus create Unreal Geometry.
The RBB is like a cookie cutter, or a template. Make it into a shape, and then use that shape to create a new additive or subtractive brush that will alter the map's space. The basic procedure is this:
- Click on a Brushbuilder button in the toolbox: the red builder brush is forged into a new shape.
- Position it in the map (mouse control explains how to do this).
- Click on one of the brush operations in the toolbox – usually Add or Subtract.
- A new world brush is placed in the map, with the exact position and configuration of the RBB.
- You can move the RBB to a new spot and add another brush of this shape.
- You can re-make the RBB into a new shape.
 Using the RBB
 Starting from scratch
The RBB can take on an entirely new shape:
- Using the buttons in the Brushbuilders toolbox group
- Using the 2D Shape Editor
- By imitating an existing brush. Do: Brush Context Menu -> Polygons -> To Brush
The red builder brush will wrap itself on the selected brush. All the surface properties, such as texture, texture pan, and Surface Flags (UT) are copied to the RBB too.
 Editing the shape
Once you have a shape, there are many ways to modify it. Note that most of these methods can also be used to alter the shape of world brushes.
- The position of individual vertices may be changed by Vertex Editing.
- The overall scale can be changed:
- Other transformations such as mirroring and skewing are also possible; see Brush Transformation.
- Rotating with the brush rotate tool.
- The Brush Clipping tool makes a planar cut through it and keeps only one part.
- Intersect crops the brush using world geometry.
- Brush Hacking is a way of editing polys and vertices.
 Saving the shape
- Brush Exporting And Importing
- Brush Preservation preserves the RBB without saving t3d files and/or preservation via adding and subtracting.
 Scaling or rotation behaves oddly
The RBB remembers its scaling and rotation, even when you give it a completely new shape. If it does not appear to do what you want it to, do one of the following:
- Check its properties, under Brush -> MainScale and Brush -> PostScale
- Do Brush Context Menu -> Reset -> Reset Scaling or Reset Rotation to reset the brush transformations
- Do Brush Context Menu -> Transform -> Transform Permanently to preserve the current shape