The level tool sets the land the brush effects to a specified level.
Brush: The size of the brush affects the number of pixels that are affected when the tool is activated. Use the circles for a quick change in size.
Level Height: sets the height that all the pixels under the brush will be set to.
Is Absolute Height: when checked sets the pixels under the brush to be this height. When unchecked, sets the pixels under the brush to be locked to a level specified at the point of clicking plus the level height.