Triad said I could post the instructions, so here they are.
1. Download
UDK (hurdur). If you want skiing and jetpacks, download
this version. I'd recommend watching the video for more info on everything.
2. Open up FELT or the Legions test client and play the map you want the heightmap from.
3. Hit F11, Window >> Terrain Terraform Editor. Then go to File >> Export Terraform Data. It'll export a .png image, which is the heightmap.
4. Open that .png file in Photoshop and save it as a .tif file. I'm pretty sure you can just save it with the
default settings.
5. Download
HMCS. Once open, go to File>>Open and set the file format to .tif, and search for the heightmap you saved in step 4.
6. Save it as a Unreal G16 Heightmap BMP image.
Because I'm fabulous, here are a few Legions maps already converted to G16 Unreal BMP.
7. Open UDK Editor (not UDK Game), choose New Map. Doesn't really matter what map template you choose after that, but I'd recommend choosing one of the Lighting ones simply because they have lighting and shadows in place. You'd have to add that stuff manually on Blank Map.
8. After you've chosen a template, close any other open windows, then choose the Terrain Editing Mode button the left toolbar (looks like mountains or some crap).
9. Once that window is open, next to the Import button select Heightmap Only, then press Import. Open the G16 bmp you saved.
10.
DON'T FREAK OUT. The map will look very very messed up. This is due to scaling issues. As I've said before I have no idea what the proper values are, so you're gonna have to guesstimate from here. If you don't see the map simply move around a bit or press F to turn off fog.
11. Right click anywhere on the map and select Terrain Properties (top option). In the box select the Display tab. Leave X and Y the same. Z is the one you want to edit. Anything from 20-35 seems right for most Legions maps, though I may have selected 40 for one of them (I can't remember. Again, guesstimations. ). Press enter/click away for the changes to appear.
That's pretty much it. Of course, the maps lack any terrain textures. Those can be added using the content browser. If you need instructions on how to do that I can provide them. If you're using the regular UDK kit you shouldn't have any issues. If you're using the PFF source however, there are some things you should know. If you play the level from within the Editor, DON'T HIT ESCAPE TO LEAVE. Open console and type exit, which will put you back into editting mode. ESC crashes the entire client. You'll likely notice skiing/jetpacks also aren't applied automatically. This can be fixed by hitting the binocular icon at the top tool bar (left of the content browser) and going to the World Info actor (likely very last one). Select it, then hit properties. Under Game Type, select FFCTFGame for both Default Game and Game Type dropdown boxes. If you watched the video from step one
you'd know this.