Create a terrain model in your favorite 3d modeling app (<ahref="http://www.blender.org/">Blender</a>, <ahref="http://www.earthsculptor.com/">Earth Sculptor</a> or any other, which can save or export a model to Wavefront .obj format)<br/>
Use <strong>File -> Import -> Wavefront .obj as Terrain</strong> action to import it as sectors. Each polygon in your model will be transformed into a sector.</p>
<em>Scale:</em> self explanatory. The default is 1.0.<br/>
<em>Up axis:</em> should be the same as vertical axis in the 3d modeling app used to create a terrain model.<br/>
<em>Sloped terrain:</em> when enabled, the mode will generate sloped terrain using floor vertex height offsets ("ZFloor") in UDMF or Vertex slope floor (1504) things. Regardless of this setting, the mode will also set each new sector's floor height to the averaged height of a polygon it was created from.<br/>