Real3D is a proprietary thing that goes beyond just producing the input. It's based on real physical light polarisation. That's why it only works on respective TVs and in Cinemas. Similarly, the actual encoding of a suitable data stream requires e.g. A blu-Ray 3D authoring tool, so ultimately whatever you do in AE can only provide the raw input for the proccess. Conventional side-by-side or interlaced output can be produced with the 3D Glasses effect or manual techniques, but naturally you will need to configure your TV manually so it's used as stereo 3D. Again, most of that has nothing to do with AE.