You can modify the terrain with a sharp brush so the edges are not smoothed or you can use a brush with a "Falloff" to smooth the edges at the same time as you are raising or lowering the terrain.
A part of the tool may be hidden when you use it the first time, simply click on the arrow at the bottom to see the whole tool.
You can select the different mousetools by using the buttons at the top of the tool.
"Additive Height" is the mousetool where you can raise and lower the terrain.
"Fixed Height" sets the terrain to a specified height.
"Smoothing" is the tool used to flatten(smooth) the terrain.
Depending on the tool you are using you can adjust the settings for the tool.
For the Additive Height Tool you can change how much the terrain will be raised or lowered when using this tool.
For the Fixed Height Tool you can define on which height the terrain will be set using this tool.
The settings for the Smoothing Tool are slightly different, you can change how intense the smoothing is. If you change a small amount the smoothing will be slow but you have lots of control over the smoothing process.
If you change a higher amount the smoothing will be much faster but you will lose much of the control over it.
The Brushsettings are working like the default ones, explained earlier, there are no special features in this tools. If you want more informations about the brush tool click here.
At the bottom of the tool you can find the functions that will change the entire map. They don’t use the brushes like the other tools do, they use their setting to change the whole map with a simple click.
The option "Single Step" is used if you need more control when modifiying the terrain.
Usually you change your tool and hold down the mousebutton to “paint” into the map, with this option
activated you have to click for every single “paint stroke” again and again.
"Raise World" sets the entire map to the value you have set.
If you turn on the Ignore Ground option, then everything that has a height of 0cm will
be ignored by Raise World.
Recalculate Aviatic Heightmap is used to render the pathing grid for flying units.
When you change the height of the terrain the grid for flying units is still on the old height, so units you place will propably be in a hill or mountain.
When you save your map this will be recalculated automatically, so commonly it’s better to save your map instead of using this button.
Most of the tools and functions that modify the geometry of the terrain are used by left clicking your mouse with one exception, the Additive Height Tool.
In this Tool you can raise the world by left clicking but if you want to lower it then you have to use the right mouse button.