The OpenSceneGraph is an OpenSource, cross platform graphics toolkit for the development of high peformance graphics applications such as flight simulators, games, virtual reality and scientific visualization. Based around the concept of a SceneGraph, it provides an object oriented framework on top of OpenGL freeing the developer from implementing and optimizing low level graphics calls, and provides many additional utilities for rapid development of graphics applications.
http://www.openscenegraph.org/

The goal of VTP is to foster the creation of tools for easily constructing any part of the real world in interactive, 3D digital form.

This goal will require a synergetic convergence of the fields of CAD, GIS, visual simulation, surveying and remote sensing. VTP gathers information and tracks progress in areas such as procedural scene construction, feature extraction, and rendering algorithms. VTP writes and supports a set of software tools, including an interactive runtime environment (VTP Enviro). The tools and their source code are freely shared to help accelerate the adoption and development of the necessary technologies.
http://vterrain.org/

I need to do 3D building modelling from a laser scanner point clouds. Is anyone else interested in this?