Maisth

Haven't gotten into the Unreal thing till UE4, all complex shapes are made completely outside of the editor.

Source shapes are all made in the Editor of course by different windows but you don't have to open another program to make it,

Unreal 2 Has a individual way to make by opening another window which lets you create all sort of stuff, there's a vertices mode that allows you to edit shapes also in both X, Y and Z