Tobias Ebsen has created a Syphon plugin for After Effects where AE can act like a Syphon server and send off a live preview to any Syphon client. Syphon is used quite a bit in the projection mapping world along side other tools such as MadMapper.

AESyphon is a plug-in for Adobe After Effects that acts like a Syphon server and provides a live preview to any Syphon client. Just drop the file in the Plug-ins folder, start After Effects and you are ready to go.Tobias Ebsen – TobiasEbsen.dk

Syphon is an open source and light weight Mac OS X technology that allows applications to share frames, either full frame rate video or stills, with one another in realtime – and it does this with little to no overhead at all.

With the AESyphon plugin in After effects you can make adjustments to an animation while having the animation show live in the projection or display mappings in MadMapper. Note that the plugin is featured on Tobias’ site under the “experiments” category – even though there is a free trial available, with a full version for $20.00. Check out the AESyphon here. There is also more information on AESyphon over at Create Digital Motion here.