© Mark Platten 2006


camera matching:
modelling & compositing

- 3ds Max
- After Effects

Top: Original footage
Centre: Final composite with camera-matched model
Bottom: CG spliced with original footage

The process of camera matching - rendering CG elements through a camera whose movement exactly reproduces the camera moves in a given piece of live footage - allows CG elements to be seamlessly integrated into footage; viewed from the exact same angle as the camera used to film that footage. C4's seductive 2005/6 logo idents are exemplars of the method.

There are two approaches to camera matching: The first uses a motion control rig to record a live camera's exact position & movements; this data then drives the camera in a 3D application, as used in some earlier work (view)

While mechanical motion control is a proven method, the scope of what can actually be filmed is physically limited by the location and size of the camera motion rig.

The more recent approach - using a software-only solution - can, in theory, derive camera motion from analysing any given piece of live footage. Here, the application Boujou was used to extrapolate a motion solution from aerial footage. Software developers make many claims on their products' behalf: practically, the bottleneck came trying to reconcile the camera data exported from the analysis phase with the modelled 3D scene. More research required...
  My initial contributions to the shot consisted of
extensive modelling of the CG buildings.

I then handled various processes at the compositing stage: matching the graininess & colour of the live footage, blending in the CG to the surrounding environment; adding lighting effects such as duplicating the lens flare which appears on the original live footage. A number of different 3D passes of the scene were generated prior to the compositing stage.

In contrast to the night shot generated from the same scene (view), blending in the edges was more critical here; with the overlapping edges of the cg elements thrown into sharp relief. And, as well as having to rotoscope in these blends, there were numerous instances where the overlaid cg had to be masked out in order to sit at its proper intended depth within the footage - again, thanks to the moving camera, requiring rotoscoping.
< original/CG (requires QuickTime 7.1)