Blender ASE Export Script
This is a fork from the original project by MCampagnini. The script has been upgraded to support Blender 2.78a and Blender 2.80 (check the Releases).
This addon has been superceded by io_scene_ase.
You will find a new export option in File / Export called Ascii Scene Export (.ase). If you do not see the script in the export menu after following the installation instructions, open the Add-On tab and find the script under Import-Export: ASCII Scene Exporter. Be sure that it is enabled by checking the box next to the add-on name. Contact me on my website if you still have problems exporting.
Assign a mesh as a collision object by prefixing each object name with UCX_NAME, where NAME can be anything you would like (case-insensitive).
Assign smoothing groups by edge selecting the border of the faces you want assigned to a smoothing group, press ctrl+e and mark sharp. Any face group separated with sharp edges will be assigned a smoothing group.
Apply vertex painting in Blender as normal, be sure that you have at least two uv texture slots. This is not a technical limitation, but due to time constraints I left the vertex painting code inside of a conditional that requires two uv textures. In order to view your vertex painting in UDK you will have to import and set up your materials correctly within UDK.