Basically, the obstacle viewing tool for all standard terrain types is now ready: mud, sand, grass, snow, swamp, rocks, underground, lava, and water (currently only supports 1 ship or 2 ships – the hero battle mode is not yet available...).

So, you download the editor and either open a map, find a cell where you're interested in seeing the obstacles on the battlefield, and click the button to view them.

Alternatively, you launch the editor, select the terrain type and two coordinates (x and y) in the corresponding windows, and click the "obstacles" button to view them on the battlefield. This mode is primarily for online players (although there's currently an issue with how to determine the coordinates in the game; a script for TE/VT would be needed, but there's a problem with that in the community).

Here's the link: http://www.phomm.narod.ru/programs/h3mtered.htm. There's also a sample map on the page to show what this whole thing is for.