View Full Version : Ghost effect in AE- How to do ti?


Joseph Dono
December 11th, 2009, 03:09 PM
YouTube - Why you should wear a seatbelt (http://www.youtube.com/watch?v=DTeKrKRDBCw)

I'm doing a project like this, how do I do the effect of the souls like this.



Cheers,
Joseph

Gregory Gesch
December 11th, 2009, 06:14 PM
Hi Joseph. The general principle is to lock off your shots and have the actor do all the action but start (and/or finish) in the 'dead' position. Duplicate your footage and in the lower layer freeze the 'dead actor' frame. In your upper layer add Effects/Tint and change the white to light blue then add Effects/Glow and pump up the Radius and Intensity, then set the layers opacity down to 33(?)%. With any luck you won't have to roto the actor????? The body floating shots would need to be greenscreened and matched to the actor beginning to stand. They also use something like Effects/Turbulent Displace when the spirit is about to re-enter the body. Hope that gives you a starting point that helps.

Nathan Moody
December 12th, 2009, 10:35 AM
Another technique worth investigating is difference matting. Assuming your live plate is locked off and there's no major movement, you can take the difference of the live plate and the action plate (the actor/ghost moving around) and then use that to derive a mask. Can help get rid of any slight offsets (which appear as repeating edges or blurriness) of overlaying two pieces of footage. This is a little advanced but worth trying, even after your production is done, to practice/try it out.

Gregory's technique will work too, but the slightest, teensiest offset (angle, position, height, focal length, anything) will create the blurriness I mentioned above...but that's what "garbage mattes" are for. You can avoid detailed roto work by just creating large, rough, feathered masks to generally isolate the actor to remove such issues.

Block your shots without moving trees, grass, or anything wind-driven in the background. Saves many headaches. ;-)

Joseph Dono
December 13th, 2009, 01:00 AM
Hmm lets say there will be moving objects in the background whats a good way to fix that? Also would using a 35mm adapter help any?

Gregory Gesch
December 13th, 2009, 05:13 PM
Both Nathan's and my techniques rely on the background plate being still and the ghost figure being the only thing moving. If there is no movement directly behind the actor at any point you might be able to do as Nathan suggests and get away with using a rough garbage matt, but if there is any movement directly behind him it would mean shooting in a different way and rotoscoping the actor. Shoot the scenes with the background action and the actor frozen for the length of time that the shot needs to hold, then cue the actor do his actions (make sure no moving shadows are going across him once he is moving - you can forget about the background as you'll be cutting it out) You then composite it as 2 layers - the lowest is your background footage of the dead actor, the top is the rotoed moving ghost image with affects added. An adaptor wouldn't make any difference as it's any sort of movement in the frame that creates the issues.