I'm working on a micro-budget action feature in which there is a lot of gunfire and actors flailing around having been shot. I've been tasked with tracking bullet wounds onto these actors who often rotate and slide about, temporarily obscuring the areas in which they've been wounded etc. Unfortunately in none of the scenes are there any tracking markers on the actors, nor is there any make up to help with wound placement.
The fundamental issue seems to be making whatever image file I'm using for the wound (e.g. from the VC Action Essentials pack) contort and rotate as the body crumples in response to being hit,about the z-axis of the actor. For example, in one scene a man wearing a white shirt with grey tie is shot; he rotates on the spot then falls back against a wall leaving a blood trail smeared behind him (the tie waves around blocking things and obscuring areas I'd been tracking). His shoulders both roll inwards as he falls backwards, then open apart as he slides down the wall. Even after successfully tracking the wound image to a specific point on the shirt, due to the way he moves, it still looks horribly out of place.
I guess the basic question is that in circumstances like these, is there a typical technique or piece of tracking software that people would tend toward? I've been working with Mocha AE and the various trackers within after effects as yet to no avail.
on Sep 3, 2017 at 5:45:53 pm Last Edited By Leopoldo Perizzolo on Sep 3, 2017 at 5:51:06 pm
In cases like this one I would recommend a 3D track of the body (the torso should be sufficient), basically using some advanced software such as PFTrack or Boujou; even if you're on a low budget, you may be able to download a free trial version that lets you track for a couple of weeks. Otherwise, you could try AE's camera tracker in reverse (see this link from VC at 6m 53s:
, although it usually refuses to solve the camera in very low contrast scenes, without markers or if the subject is far away...even more if not even Mocha can get a good track) or as a last resource a 3D manual track.
Since all those methods work in 3D, you can use some sort of fluid simulation and get a realistic result even when the subject is turned sideways from the camera. If you don't know how to work with simulations, you might get away with just multiple layers stacked at different angles.
If you absolutely can't pull off a good track, a simple solution might be to fake it. One way would be using a lot of motion blur, another speeding up the scene (as long as it preserves a natural movement) with a bit of forced motion blur, or maybe by pulling a rack-focus as soon as the subject gets hit.
The very last suggestion is to re-shoot the scene. Often times it's the only way to solve this kind of problems.
There's no magic in softwares, if you can't tell by yourself what the movement should look like, there's no way a program can do a better job than yours. Sorry, that's just the way it is ;P