Most mobile 3D applications use scene graphs in resource files to describe objects, scenes, and characters. Usually it is not programmers but graphic designers or artists who create the scene graphs, using standard 3D modeling tools.
Several vendors offer tools for authoring content and converting files to the JSR 184 format. Superscape (http://superscape.com/) is one such vendor.
Because it is relatively difficult to create and manipulate 3D graphics content in an application using the immediate mode API, most applications rely as much as possible on a scene graph file. By putting as much as possible into the scene graph file at design time, the application’s job at runtime is considerably simplified.