Hello everyone,
For the last few days I've tried to build a prototype level using only UModeler. Even though I'm not a modeler but a programmer, modeling something with UModeler was very easy and fun because I just drew what I want and make it 3D or cut it out using push/pull tools to model complex shapes or curved geometries. With other modeling/prototype tools it would have been hard to make such things.
It wasn't taken long time to build the following objects. For example it was taken just 5 mins at most to make the destroyed gate which is the third object below.
The screenshot below shows a prototype of ruins made only with UModeler by putting all of the upper objects together. I've not happened to face any crash errors, broken polygons and performance lag etc while modeling them, which shows that UModeler in the recent version of Unity is very stable.

I'm going to make tutorial and demo videos to show how to build them.
Therefore... stay tuned!