Installing Left 4 Dead SDK Authoring Tools and Google's SketchUp.
In the following video I explain how to install the SDK and Google's Free Tool SketchUp.
1. Log into your Steam account and click on Tools tab.
Right click and hit install on L4D Authoring Tools.
2. Download free Google's SketchUp program here. Choose the free download and install it.
3. Launch SketchUp to make sure it works.
4. Install the plug-ins to SketchUp from Steam's SketchUp Plug-ins.
Copy All from here:
and Paste it all to here:
5. Launch Google's SketchUp and under plugins you should see Export SMD and Export VMF.