I’m not sure if this functionality is built in yet, but I would like it to be possible to instantly find your builder brush in the world by hitting something like B in the viewport. Currently it’s very easily to lose your builder brush entirely and you can spend ages looking for it, especially in an expansive level 
Edit → (Configuration) → Keyboard Shortcuts
The command is called ‘To Builder Brush’ and by default is not assigned to any keys.
Amazing, thanks Luke! Was sure I’d seen it somewhere in UDK
To Builder Brush will bring the Builder Brush up to whatever volume you have selected. It will make it match the shape also, so that you can easily place a matching volume.
You can also hit F2 to just select the Brush in the viewport, then hit ‘F’ to focus directly to it.
Cheers!
Alexander
Hi!
Is this functionality still in 4.8.2? I searched the through the Keyboard Shortcut list for “To Builder Brush” and couldn’t find it. Builder Brush visibility toggling also seems to be gone from the viewport’s Show>Advanced menu. I’m in a situation where it would save me a lot of time by having a builder brush take on the shape of a procedural foliage volume. Thanks!
-Sam
yeah I’d like to know this too. I’m using 4.9.1 and it still seems missing