Hallo, Modding-Welt weil mein deutsch nicht gut ist habe ich diese Tut im Englisch übersetzt
(In this Tut you need to have some basic understanding of modding and fs)
Step 1;
You need to open your model in Blender
Step 2;
On the bottom left you need to select Uv/Image editor. (You can size this part to what you like, i made it bigger but that depends on what you like!)
Step 3;
When the model is selected you need to press "Tabb" on the top lef of your keyboard.
Step 4;
Afterwards you need to press "U" ----> smart UV project and then Island Margin on 0.03.
Step 5;
Now you need to tap on the button +NEW and give the ao file the size you want it to be ;).
Step 6;
Go to top right and hit the World, then choose ambient occulision and scroll down to change the amout of Sampels (I prefer to use 15, but that's just what you're pc can do and what you prefer)
Step 7;
Go to the Camera on the right top in close range of the World, scrol down and choose "Bake ambient occulision" instead of "bake full render" .
Step 8;
Let blender bake the Ao py pressing "Bake"
At the end you need to press "F3" And save the Ao, and export the model as .obj
I hope this suits, but i'f you have got any questions feel free to ask them!
Groetjes Inter Fan