Heightmaps in the Mission Editor:

The Basics:

Select the Heightmap Editor from the ME toolbar. When you move the cursor over the terrain, you should see a pair of white circles drawn beneath it. These are the brush with which you will paint and sculpt the terrain.

The options in the tray are:

• Mode: Additive, Subtractive, Set Value, and Smoothing
• Brush Size: This controls the outer circle of your cursor (Moving the mouse while holding down SHIFT+Left Mouse Button will also change the size of the brush).
• Feather: This controls the size of the inner circle of your brush.
• Height: Allows you to set an explicit value, which only works when "Mode" is set to "Set Value"
• Presets: A usesful set of named, selectable height values.
• Strength: Allows you to adjust the magnitude of your brush.

All the terrain within the inner circle of your cursor will be affected at the strength you set. Between the perimeters of the two circles, the effect fades uniformly from maximum strength to nothing. When using Addition or Subtraction, holding the mouse button down and moving the mouse will generate some extreme results. The best results come from gradually bulding up the terrain, so remember: short, controlled bursts.

Set levels will raise or lower the terrain to the preset height you choose.

Smoothing will get rid of any jaggedness, as shown in the before and after images below:

Water Level:

The level of the water is fixed at a single value which cannot be changed. It runs under the map as a continuous sheet, and to make it show you have to lower the terrain past it; there are relevant preset levels in the terrain editing options. Water sometimes won't show up properly where it should until after the map file is saved.

Terrain Type Editor:

The first option in the tray is a drop down list. "FootFall" is not implementd, so ignore it. The other item on the list is Cover. The game does not automatically make craters into heavy cover, etc, you have to paint it on yourself.

The drop down list is buggy, sometimes the bottom one will show the wrong option, and sometimes they'll hold on to the mouse pointer focus and make the 3D viewport seem unresponsive, so double check them.

The only four options on the cover list you need are None, Light, Heavy, and Negative, which will be self explanatory to anyone who has played the game.

Blocking and Stealth cover are not implemented. Blocking is meant to prevent the construction of buildings, and stealth is meant to automatically cloak any units within it. They don't work though.

Painting Impass Maps:

The impass map tells units what areas they can stand on and travel over, and what areas they cannot. The ME will automatically generate an impass map on the basis of what gradient a piece of terrain has, but as you can see in the picture below, it is not perfect:

You have to use the Impass Map Editor to tweak it. The list in the tray has three options:

• Generated: This resets terrain you paint to the ME generated default impass map.
• Passable: This explicitly denotes terrain as passable, no matter how steep it is. This shows in a brighter shade of grey than the default passable terrain.
• Impassable: This explicitly denotes terrain as impassable, no matter how flat it is. This shows in a brighter shade of red than the default impassable terrain.

Terrain Bugs:

These mainly come in the form of jaggies, which will occur all over your terrain whether it is done in the ME or an external editor. As with the example pictures above, the smoothing tool can sort them out, shown by these images of the bottom of a steep cliff descending into water:

Jaggies will have several effects, including distorted decals and placed meshes being absorbed in part by the terrain or hovering above it. Such effects can be minimised with the smoothing and other terrain tools, though never completely eliminated. The most obvious example would be the terrain above the water on Deadman's Crossing: some of the strategic points hover slightly, and the ground tends to absorb parts of building meshes, which is especially visible with the Machine Cults and Eldar portals.

Jaggies will also create small fragments of impassable terrain, viewable with the Impass Map tool. A quick and dirty cheat to get rid of them is to just paint them as passable with the Impass Map Editor, but a better solution is to use the smoothing tool and if necessary additive and subtractive painting to even out the ground.

Another terrain bug to look out for is paths that are too narrow for vehicles. Or would that just be a feature? ;)

A final, very important thing to note is that working bridges are not possible in Dawn of War. Basically, if units can travel over something, anything underneath will become impassable, so take that into account when you design.