I created hexes and they work fine. Now I wanted to add 3 trees on some of the hexes. The trees have collision, so I can’t place figurines on top of them in Tabletop Simulator. But I want to put stuff there. How can I make stuff visible but have no colission with other objects so a figurine can standIN the trees?
Can someone point me into the right direction? I had problems with objects falling through and someone said it was because my model had its face on the outside due to strange negative-scaling etc. He told me to hit CTRL-N to make all faces be front-facing faces.
Would the easiest / cleanest solution be to somehow mark the whole tree and then turn all its faces to inside faces? But then it would become invisible, too? Hm. Can someone help me? 
Ok, I found out how to do it in Tabletop Simulator. Just export what you want to see as ONE .obj, and then the collision as a 2nd file and paste them into the first field and the collision field … I tried to solve this in blender but it is solved outside.