Hi D-Kaf, the base technology that MoI is based off of is more oriented towards making broad smooth surfaces, it's not really very well suited for the kind of irregular organic details like you're describing.

Those kinds of things tend to be better suited for either polygon mesh based programs such as Modo, Cinema4D, Maya, etc... or also displacement brush based programs like 3D Coat or ZBrush.

There aren't a lot of tools for doing what you're describing mostly because MoI is just not really suited for doing that kind of thing. You can use MoI in combination with one of those other programs if you want though, for example build a smooth cobblestone section in MoI and then bring it into 3D coat and then do some editing of it in there to add roughness and irregularity.

If you just want to randomly scale cubes, that's possible in MoI by a plugin, in addition to what was described above, here is one that can do a random move or scale of a set of boxes:
http://moi3d.com/forum/index.php?webtag=MOI&msg=5416.5

But that won't really do a "degrade" type effect like you're asking about, if you want the boxes to have chunks eroded away and have a sort of weatherbeaten effect that's the type of thing that you would want to do in a different program that was more oriented around organic modeling. You might try 3D-Coat for that.

- Michael