just thinking out loud... haven’t done this but it sounds like an interesting challenge.
you could track a scanned face to the filmed one (I think pftrack can do this and others too) that could be a good starting point to correctly place the eyeballs – remember the eyeballs would be sitting at a fixed position in the head – you could even try to import a detailed skull model and align it with the scanned head actor to help with placement of the eyes. make a rigged pupil for each eye, with its pivot in the center of the eyeballs, then track/animate the pupils by hand using just x and y rotation. add some nulls or lines from the pupils outward – see if and where they diverge - this could give you in theory an approximation of where the person is looking. I wonder if this could give a useable result? perhaps within a very controlled setup. I’ve hand tracked some totally different things to footage, in a comparable way, by setting up a simple rig that would mimic what I knew from how the real subject worked – and ended up with more useable results than brute force camera tracking software would give me. From: Scott Lange Sent: Monday, March 04, 2013 7:36 PM To: [email protected] Subject: Tracking eye-lines Happy Monday Folks, Any suggestions on tracking eye-lines in live action to follow a 3D character? I haven't had to do this before, to this level of specificity. I am pretty good on general tracking, just looking for something to save me a little time. Thanks Scott Lange Animation and VFX 347 256-7247
