I got a 3D-file (3ds). I would like to animate it.
In Photoshop there all layers and the gfx is perfect.
While importing the file into After Effects, I should chose "Live Photoshop 3D", but there isn't any possibility.
This should be an add-on, plug-in, etc.
Does anybody know, how to get it..?
There is no such thing. These features have been removed in curent versions of AE. They only existed in CS5 and CS5.5 but never worked well in the first place.
What version of AE do you have? If you have CC or CC 2014 (versions 12 and 13 respectively), you can use Cinema 4D to render this. Cinema 4D Lite comes free with After Effects! details of CINEMA 4D integration with After Effects CC