I have a model in Blender, which I have tried to export into Adobe After Effects as .obj and adobe after effects file (.jsx). None of these open in After effects. Does anyone know how to export it?
After Effects is not a 3D program, therefore it can not import 3D objects by itself. There are 3rd party programs that can help import an OBJ file. One of the best is Element 3D by Video Copilot ($200). After Effects also comes with Cinema 4D lite which has built in pipeline for working with 3D. You could always export from Blender into Cinema 4D and then use the built in pipeline to get it into After Effects.
Hope this helps.
The .jsx file can, in fact, be "opened" by After Effects, and can give you camera and null (empty) data from after effects.
The thing to realise is it's not a file to import in the conventional sense - rather, it's an automatically-generated script that, when run, will recreate the animation data. So you need to create a new After Effects project, then run the .jsx file via File > Scripts > Run Script File. That'll give you the animation data.
However, After Effects cannot natively display 3D models - it's a purely 2D compositor, so a common practise is to render multilayer .exr files and load them as image sequence.
You can also export an FBX (which contains fully animated 3D data) and use Cinema 4D Lite (which is a integrated with After Effects and included in Adobe Creative Suite) to load and display it with After Effects.
Of course, the cleanest solution is not to bother with After Effects at all and just use Blender's built in node-based compositor, which can handle many of the same functions and is often much faster.
You Better Export Your Animation as Image Sequences and use EXtractoR Plugin... you can check this video too for further instructions https://www.youtube.com/watch?v=thc0-1ze8po