In TrenchBroom, there are three types of objects which can be selected: entities, brushes and faces. In the following sections, you will learn how you can select these objects to edit them. However, it is not possible to select any combination of objects. You can select multiple brushes and entities together because most editing operations can be applied to both these objects. Faces are a different matter though. You cannot combine faces and brushes or faces and entities in the same selection. Selecting a face will therefore deselect any selected brushes and entities and vice versa.
Selected objects are rendered with red edges and slightly tinted faces to distinguish them visually. The bounding box of the selected objects is rendered in red, with spikes extending from every corner. These spikes are useful to pecisely position objects in relation to other objects. If you hover the mouse cursor over a selected object, the bounds and spikes are rendered in white, and the size of the bounding box is displayed as well.
To select a single brush or entity, you simply left click on it in the 3D view. To select multiple objects, hold while left clicking. If you click on a selected object while holding , it will be deselected. Please note that you cannot directly select brush entities by clicking on them. Read below to find out how to select such entities.
Faces can be selected by left clicking while holding . To select multiple faces, again hold . To select all faces of a brush, left double click the brush while holding . To add all faces of a brush to the current selection, additionally hold .
To deselect everything, simply left click into the void, or choose from the menu.
If you need to select many entities and brushes which are close to each other, you can use selection brushes. A selection brush is an ordinary brush which was usually created just for the purpose of selecting other objects. To use a selection brush, create (and select) a new brush that intersects or contains all of the objects that you would like to select. Then choose and all objects which the selected brush touches are selected. Be aware that the previously selected brush is deleted by this operation.
Look at the above images for an example. Say you wish to select the two columns and the info_player_coop entity. For the sake of the example, you want to use a selection brush. So you quickly draw a brush that touches only the columns and hit . Voilà - the objects are selected.
In the Edit menu, there are several other commands that help you to select objects. Choose to select every visible entity and brush in the map. If you want to select all brushes belonging to a particular brush entity, you must first select one brush which belongs to that entity and then choose . This selects all brushes of that brush entity.