For those of you that are missing DLLs, do a search on
google and download them. You can find installation instructions for DLL files there as well.
For those of you that don't understand what a heightmap is--obviously, this tool will be of little use to you. The explanation that gadax gave is about as good as it gets.
The purpose is this tool is that the WE doesn't allow you to create steep terrain. Normally, you'd use the tools under the "Apply Height" section to raise and lower the terrain, but the WE forces it to be a gradual, more realistic effect. So if you want steep terrain, you have to use a 3rd party program like this one.
To demonstrate the effectiveness, I took a class image of a ying-yang. Heightmaps work on shades of gray, and ying-yangs are traditionally black and white. I decided a good resolution for the map would be 128x128, so I resized the image to be 129x129 and saved it as a targa.
Download the TGA
So once I had that saved as a targa and a new 128x128 map created, I used the tool to supply the paths to the two files and generated an Environment file (war3map.w3e).
Then I used WinMPQ to open the map file (*.w3x), deleted the
(attributes) file, and dragged my new
war3map.w3e file into the archive to overwrite the old one. Then I closed WinMPQ and opened the map in the WE.
This is bird's eye view of the new terrain. You can see how well it matches the ying-yang heightmap.
Next, I angled the camera down and got a shot from the side to present how the height map works in 3D. Since my height map is pure black and white, there are only two levels of terrain. Everywhere that the image was white is very high, and where it was black is very low. You can use shades of gray in your own experiments in order to lessen the extremes.
Finally, to demonstrate the benefits of this over using the cliff tool, I added a bit of terrain to this circular pocket. You'll notice a few things here:
1) The variation between high and low terrain is significantly greater than can be achieved through the cliff tool.
2) I'm no longer limited to using one of two types of terrain on my cliffs--they can be any available terrain and those terrains can even touch each other.
3) The edges are a near perfect circle. Using normal cliffs, you're forced to apply the height on a tiled pattern which makes it impossible to create curved edges.
I should note for all the newbies out there that, since the game does view this as a deformation of the terrain and not a cliff, the game will allow ground units to walk up and down them as freely (and quickly) as over normal terrain. The easiest way to prevent this is to use ground pathing blockers (in the doodad pallette) at the bottom and top of each cliff.