Forboding Angel wrote:Ack, didn't see this.
Well, if you want to create your heightmaps completely outside of l3dt without any l3dt drawing, you need to import them at full texture size resolution (meaning, if it's a 16x16 map import the heightmap at a size of 8192x8192, then once it's imported, scale it down to 1024x1024), then scale them down within l3dt.
Another thing you can do if it's smoothing too much (which is what I normally do) is raise the heights in l3dt to something ridiculous, like min 0 max 1000-3000, alternately, you can fiddle with the horizontal scale.
^^ I need to point out that the above is not necessary unless you plan on having l3dt regenerate the heightmap from a design map. Additionally, with 2.5c you can tell it how large to make the design map so it's worth playing around with different sizes.
Likewise with the smoothing. Setting the horizontal scale to something lower than 10 should do the trick nicely, no matter how flat your map is. I usually use 8 as a matter of course.