SourceCity is a 3D visualization tool for analyse object-oriented systems. There is a new Jenkins CI job to build a "SourceCity" image right from the metacello config.
So you just need to download the image and run with the usual Pharo VM. To create a visualization just evaluate:
Note that SourceCity is meanwhile open source with MIT license. Code can be found on SmalltalkHub.
Read more about the project here (page is a little bit slow) or here.