If you really want to analyze the source code:
http://www.clonk.de/source.php?lng=en


If you mean the terrain only, I am quite sure it is pixel based.



Oh....
Thanks for the links!
If Data does not intend to add multiplayer and CC stays closed source this discussion was quite useless...sorry.

But anyway, do you think it would theoretical be possible to make online-mp for a game like CC using the system I described? xD

Well, similar modifications have been suggested in past. I believe that the less tactful of forum members told the suggester to play Soldat, claiming that the level of simplification required would leave differences between it and Soldat as negligible at best.
Personally, I believe that to simplify far enough is to remove the ability to do a large variety of things which the game and modding relies upon.

Just my experience with "fully destructible terrain" outside CC.

In Red faction for example, an explosion creates a 3d hollow object that projects a texture on the area around it, thus creating a hole in the terrain that is traversable etc etc.

Worms does something similar, just deleting a circle of the map.

I guess CR is more of a worms clone with physics then near CC, and thus it should be easier to transfer data because it only has to transfer the position of the explosion, not every single pixel moved. It still has to transfer all the objects, but that can't be much.
Duh, I had to quote your post to read it, how damn big is your screen?

Destructible terrain is a tricky thing to try and work into a game without having it lag... too much.