Awesome! Maybe VI and VII need a bit more detailed information.

Can anybody explain how to do variation on models proper? Every variant = one model file? Is Ogre (~OgreC4DExporter) capable to interpret C4D-Joints?

Wow, that looks awesome (as well, Fungiforms sketches are also cool)! Makes me think about background decoration consisting of huge trees for deep-forest-scenarios in the background, too large to hack down (and/or slightly parallax).

For trees as a resource, keep in mind that it should to look comprehensible hacking the tree down. A trunk that is as thick as a house is probably not suitable (22). I don't think we will or should stick to the "hack tree -> a few pieces of small wood items come out" workflow in the long term, it looks very weird.
You know, I am a friend of Clonkonaut's heavy resources concept: If you hack down a tree, long logs could come out there which you have to carry to the next sawmill (carry-heavy). This would also remove the annoying task of shoving the tree around the landscape. But then, the logs should more or less look like the trunk they come from.

I'm not too sure about the colors in the context of the game though. Or colors in general. ;)

I love all the concept art. I like your climate transitions too. Keep up the good work!

Deserts have weird fauna.

Here are some thougts caming into my mind while watching your sketches:

It also would be nice to have a ton of vegetation to use in caves, old castles or ruins, crazy diamondshrooms for miningadventures and other extraordinary vegetation in vulcanos or sea and deepseastuff.
Clonk is a crazy mix of steampunk, adventure, fantasy, settlement and melee, jump n run and basefight and we also could use this in the vegetation for the game.
There could be healthy and also dangerous plants, vines to climb, thorns where u can fall in, we can create slimy ground makes u fall easy and giant trees to build houses on.

I would like to have trees a little bigger in general. (not like in the other versions of clonk were createt before, maybe like the "bigtrees" in the M&M-Adventure) That creates the feeling to be in a very big and unexplored world. It also would give us the chance to create funny (boss)monsters or animals. Actually the Clonk himselv settles the world like a human would, but make the world around the clonk a little bigger, also vegetation, animals, mountains, caves and everything would create a ton of new ways to play and feel into the world of Clonk.