Red Orchestra 2 Artillery Setup
1) Right click the builder brush cube tool
2) Create a brush large enough to surround the playing area of you map, click build and move into position
3) Right click the volumes tool and select ROVolumeMapBounds.
This volume is used, primarily, for positioning the Overhead maps. It is also used to drop artillery from.
Ideally you are going to want to have the volume ~7000UUs or more above the play area to ensure the artillery called in hits it's target.