Now you know how TV shows manage to afford the cinematic look of all that location shooting we've been seeing.

They don't.

They're using the cinematic trick of CGI, more and more, in shows ranging from 24 and Heroes to Ugly Betty and Grey's Anatomy.

It's well demonstrated in an amazing "virtual backlot" reel of work from the Stargate Studios computer-imaging folks, streaming here.

Where "green screen" work used to be fairly obvious (and before that, of course, it was cheesy to spot back-projection), the trick is now so seamlessly sneaky that it's stunning to discover when and how it's employed -- even in zooms and other kinds of camerawork that used to be dead-giveaways where the seams showed.

If you're think we're close to the time when an entire show could be produced on virtual sets this way, well, we're there already. That's how Syfy shoots Sanctuary. Before the aliens-among-us saga returns with new episodes this fall, you can watch previous outings online, on DVD, or in on-air repeats (Tuesday mornings at 3 a.m. ET, Friday mornings at 5 a.m. ET, Syfy).