How do you make organic shapes?

[Xyzzу]

I want to make rock formations like the ones in Scythe. 

 

Spoiler

 

How do I not be orthogonal, basically?

[BigDickBzzrak]

hold shift in db2, close your eyes, move your mouse around the map and click LMB now and then

congratulations, you have a non-orthogonal rock

[Nevander]

Start with a spiky basic outline of the rock formation you want to draw. Then, come back and add vertices between the first set to add roundness. Tweak it until it looks natural-ish.

[Misty]

Well, I like draw weird lines , but not that much, because texture alignments become painful process. Here, example of my stuff,this place is very messy, I just quickly textured for you.

 

P.s I'll add map plan here too. 

 

Edited June 20, 2017 by MysteriousHaruko

[Albertoni]

Second option on the left bar of GZDoom Builder is "draw curve." That might help, if you want smooth instead of jaggy.