Matchmoving is a cinematic technique that enables computer generated graphics to be placed into a live-action footage. The graphics should be placed into the real footage where they appear to move as if they were part of it with the correct position, scale, and orientation of the photographed scene. It can simply be describe as the process to match computer generated graphics into a real scene. There have been great developments in VFX especially the film industries due to evolving technology.
The creation of special effects has permitted a high level of integration in movie production. To make this appear accurate as if these CGI are living alongside the actors, there is need of a virtual camera that moves exactly like the camera in the live action footage [ref 1]. Matchmoving plays the major role in this technique to combine CGI and element in a real scene. A camera when used in filming a scene, is basically capturing a 3D dimension world into a 2D plane.
Though the image when played appears to be a 3D scene, the results is just a projection of the flattened 3D scene. The portal between these two dimensions i. e. the 2D image and 3D dimension is the camera. The contrast to this technique is camera tracking, which is to reconstruct a 2D scene using an algorithm referred to as photogrammetric in order to create a 3D environments that matches the set up at time of filming. This is very important to accomplish any VFX into a live footage. To understand this method, let’s consider a typical VFX shot.
A director has planned to film a real scene and a CG creature is to run across a street and smash into a cafe through a building window. On the day of filming, the camera man and the director will decide on the shot and camera position. This shot will be practice as well as the camera move to accomplish the scene, once satisfy the scene is captured even though the creature isn’t there and extracts will react to the imaginary creature. The scene is sent off to the visual studio and their job is to add the CG creature into the scene.
In order for the creature to be inserted into this scene to appear realistically with the scene, mera has to be created that match the camera and the moves during filming. If this is achieve accurately then the final scene is never noticed to the viewer. A well created scene with matchmoving should never be noticed by the viewer. If you have done your job right, no one should ever know you have done your job at all. So despite its importance in VFX, it is completely invisible in the final shot [ref 2].
The main aim of this dissertation was to experience the matchmoving technique through a movie production workflow. To achieve this aim, I set out multiple tasks to accomplish the aim but follow the goal of experiencing the insertion of CG into a real scene. I researched the production workflow, starting from filming to delivering the final video sequence. The workflow is generally the same pattern for each shot, although there are a variety of ways to complete a task [ref 3]. Figure 1 is a typical workflow of a match moving process.
Figure 1: Typical Production Workflow. Tresearched the available matchmoving packages to choose from in order to create a matchmoving data. I researched the technique used by the matchmoving software to achieve the data, it gave me an understanding of the matchmoving techniques and the process it follows to achieve data. And finally, I produced a video sequence of about 40 secs but with no plot and storytelling line included in the video sequence as this is purely a research experiment into matchmoving techniques.
Also, this will be unnecessarily time consuming to include a script or actors in the filming process to achieve the final video. The final video will be a demonstration that insert a CG into a live video footage. This will include work on different techniques from 3D modelling, matchmoving, rendering and compositing This dissertation will help advance my knowledge and skills to achieve an accurate matched environment in 3D. Also the relevance of this study is important considering the evolution of the film industry in using VFX.
There have been tremendous changes as the technology advanced since it was first used in the 90’s. The first film to use matchmoving was Terminator2 [ref 3]. Since then, with the development of many software and a lot of research on this topic, the technique has been used widely in many movies. Some movies such as Avatar by James Cameron in 2009, Hellboy 2, Transformers, Bad boys 2, Terminator 3, etc. In the following chapters, I present the background research to this dissertation that’s covers the matchmoving technique, workflow, matchmoving software.