Convert Tribes2 Maps to Giants
First Step: Getting the Tribes 2 Map's Heightfield
Start Tribes 2 in either Single Player or Online mode, and host a game (without bots) on the map you want to get the heightfield of.
Once youre in the game, its easiest if you stay in observer mode and do not spawn, if you accidentally spawn yourself, go back into observer mode by hitting escape and clicking "observer mode" in the upper right.
Open the Tribes 2 Map editor by pushing ALT + E.
Once you're inside the editor, you'll need to enter "Terrain Terraform Editor" mode. This can be accomplished by either going to the window tab and selecting "Terrain Terraform Editor". Now that you're inside the Terraform Editor, you'll notice a green and black image in the lower left, this is your heightfield.
To get the exact copy of the map's heightfield, you'll need to go into the File tab, and select "Export Terraform Bitmap". You'll get a save window, which will save the heightfield with whatever name you want. The default directory is C:\Dynamix\Tribes2\GameData\base\terrains\heightfield, which may vary depending on where Tribes 2 is installed for you.
Second Step: Converting the heightfield into a format Giants Edit will recognize
If you don't have an image editing software that meets the requirements above, you should download Irfan View (http://www.irfanview.com/), which can do everything we need. The following instructions are what you'll need to do in Irfan View specifically, but if you're more familiar with a different editing software, it should be clear what you need to do.
Load Irfan View and browse to your heightfield file which will most likely be in the C:\Dynamix\Tribes2\GameData\base\terrains\heightfield directory. If your file does not appear, change the File Type box from "Common Graphic Files" to "All Files (*.*)" because the Tribes 2 Editor saved your heightfield without a file extension.
Now that the file is open, click the image tab, and go down to "Convert to Greyscale". You will see that the green heightfield has now become black and white.
Now, go to the File tab and select "Save File As", and name your file. From the File Type box, select "BMP - Windows Bitmap", and save the file.
Thats all you need to do in your photo editing software, now load Giants Edit.
Third Step: Loading the heightfield into Giants Edit
Once you have Giants edit loaded, create a new map file, and base it off of whatever level you want (say yes when it asks you if you want it to load terrain).
Open the File tab and click "Clear Objects", and repeat for "Clear Terrain" once the map is loaded. When you do Clear Terrain, a dialog box will pop up asking you to specify the shape and dimensions of your Terrain. You'll want to use a rectangular shaped terrain with a 256 by 256 unit dimension.
You should now have a large, square landmass. From here, click the File tab and go to "Import -> Terrain Import Wizard". Click the box next to "Load a height map" and browse the bitmap file you created in step 2. Click Next.
You can specify the settings you want here, the higher you set "Match White to terrain level", the more mountainous your map will be come. Click Next and then Finish, and your heightfield will have been converted into a new Giants map! From here, you can edit and modify it like any other Giants map.
A 256 x 256 map is quite large, though, and you can shrink it down by either editing and removing sections of the map, or by going into the Terrain Tab and selecting "Stretch / Move". Change the first dialog box, which defaults to 40.0000000, to a number lower for a map that is proportionally that much smaller (only horizontally, the vertical heights will stay the same, meaning your map may have very steep mountains).