I love those little clips. Perfect timing. I wonder if they're using a souped up Source Engine or a regular renderer (Max,Maya) for the rendering.
Ther's an article about the illustrative rendiring method they use here:
http://www.valvesoftware.com/publications/2007/NPAR07_IllustrativeRenderingInTeamFortress2.pdf
Ther's an article about the illustrative rendiring method they use here:
http://www.valvesoftware.com/publications/2007/NPAR07_IllustrativeRenderingInTeamFortress2.pdf