If you have to learn a new or have to monitor the health of a large code base, then visualizations are really helpful. For .NET there is for example NDepend [1] which also offers treemapping [2] but in the more traditional 2D version which is probably quite a bit more useful in practice than the 3D version shown here. But still it is more or less the same thing.

[1] http://www.ndepend.com/screenshots

[2] https://en.wikipedia.org/wiki/Treemapping