Avatar locations (put an NWD in a folder inside here):
C:Program FilesAutodeskNavisworks Simulate 2013avatars
C:Program FilesAutodeskNavisworks Manage 2015avatarsSOMEFOLDERsomething.nwd
Some examples for download:
Download NWavatars
Read more:
http://blogs.rand.com/manufacturing/2012/09/navisworks-simulate-custom-avatars-for-walkthrough-review.html