You can at least make it look passable though. Koyasha and Neo have outlined the modelling side, so let's assume that you have read that, and you now have a nice big wall of rock in front of you. The first thing to do is hit CTRL+B to go into brush mode, select all of the triangles which make up your terrain and hit SHIFT+J to join them together.
If you have any textures which don't line up correctly, select your brush, right click on it and select TEXTURE->Reset texture coordinates. This will remove any panning or size changes which have been made to the textured faces, and all of the faces should line up properly.
Go into the properties of your new rocky-mountain and make sure that the lighting is set to Gourad. Save, process then run. Your rocks should look kind of like this:
Notice how the edges are very harsh? In all 3D packages there is a surface property, usually called smoothing, which changes the way that light is mapped across edges to give the effect that there aren't any edges. In this way, a sphere can be created in 3D and look effective without having billions of polys. Wouldn't it be nice if you could do this in Dedit?
Well, you can
Go into the properties of your brush again, and select LightControl:
You should get this panel:
Now see down the bottom, the field called CreaseAngle? This is the smoothing control. The value of the field is the maximum angle at which an edge is smoothed. It defaults to 45 °, so edges with an angle from 0 ° - 45 ° will be smoothed, which is not really smooth enough for most terrain. Set it to 180 °, which means that pretty much every edge will be smoothed.
Save, process and run. Your rocks should look like this:
Much better
