New SDK Features
- High Dynamic Range lighting now supported in the tools
- Day of Defeat: Source support now included
- New Hammer Editor features:
- VGUI Model browser with real-time 3D view
- Map autosave/backup
- Model and displacement rendering in 2D views
- Many other small improvements and bug fixes
For a full list of changes, see the Source SDK Changelist on the Valve Developer Community site.