Crear Escaleras

Tienes que crear un brush delante de una escalera y ponerle la entidad func_ladder.

Perdon por mi ignorancia pero, ¿Que es un brush?

A brush is a convex[/URL] 3D shape created with Hammer’s Block Tool. Brushes are used by level designers to define the shape of the world (which defines visibility) and to create [URL=‘https://developer.valvesoftware.com/wiki/Brush_entity’]brush entities. When a map is compiled VBSP[/URL] converts brush faces that touch a visleaf to [URL=‘http://en.wikipedia.org/wiki/Constructive_solid_geometry’]groups of polygons. The resulting ‘brush models’ are stored within the BSP file and can be claimed by entities (e.g. the world, or your brush entity). The original brushes are retained in the BSP, though the benefits of this are not clear.