You can bake an AO in Blender too.
For that, go into the UV Editing window and make sure your UV Unwrapping is finished. Then, create a New Image :
[Blocked Image: http://i.imgur.com/FbJv9vE.png]
Choose a image resolution and fill it with anything, it will be erased anyway.
Then go back in the default Window and Object mode. On the right panel, get into the World tab :
[Blocked Image: http://i.imgur.com/GMnHxZn.png]
Check the "Ambient Occlusion" box and below, in the "Gather part", change Distance and Samples to the desired values.
I personally use 20 samples, it's enough to get smooth AO and fast enough. For the Attenuation, i find 50 to be relevant but it depends of the size of your model. For the information, i always model everything scale 1:1 (1 units in Blender = 1 units in Hammer). If you do that, 50 is a great attenuation distance value.
After that, get in the Bake tab (first one)
[Blocked Image: http://i.imgur.com/wfctcNd.png]
Go into the Bake part and configure it like that :
[Blocked Image: http://i.imgur.com/6K12u9L.png]
Normalized might not be the best to get homogeneous AO between all your models, but i prefer to use it, it gets more contrasts.
Finally, click on the Bake button and you should get your AO :
[Blocked Image: http://i.imgur.com/C18Cneh.png] (viewed in Texture shading)
[Blocked Image: http://i.imgur.com/BOnsdPT.png]
Finally : Image → Save As Image
[Blocked Image: http://i.imgur.com/Wwxd6Go.png]
Hope this helps