What is Matchmoving in VFX and its importants?
Match moving is technique to place CG (Computer Graphics Element) in to live- action Footage with all its correct position, orientation, scale and all other motion in the video.
There are 3 tasks performed by Match move artists and there can be more ways invent in future.
1. Camera Tracking
2. Object Tracking
3. Roto animation also called Matchmation
There are many tools that can be used to complete this match moving task depending on the need of the shot. Some basic software that can handle track directly in your compositing package like Mocha pro, Adobe After Effects, Nuke etc. Even some common 3d Software offer some tracking tools and features for some simple 3d tracks like Cinema 4D, Blender but also when you need the Difficult or complex solves you’ll want to bring in the specialized tracking software like PF track , Boujou, Mocha pro, 3D Equalizer, synth eyes and many more but 3D equalizer is an industry standard for this kind of work it’s so powerful capable of producing right and accurate tracks point and offer a ton of useful tools to really simplify and speed up the tracking process. Synth eyes and PF track offers similar features and can be used as an alternative to 3D equalizer and if work in shot is simple enough you also might be able to use 2d Track which is where keeping things in nuke or After effects seem interesting otherwise if the shot has enough parallax movement with lots of motion then you will need more dedicated 3d Tracking software.
Camera tracking is the first starting point of all CGI. It’s where the real world and the digital touch for the first time without it. You’ve basically got some renders randomly plastered over your footage with none of the movement matching. Simple camera tracking is the process of recreating your real world camera in your 3d software to start this process. You are going to need some original footage which is referred to as the plate to make things easy for yourself. You’ll also want to know some more information such as the camera and lens used footage of a distortion grid.
and if you’re really lucky you’ll even be able to get your hands on a lidar scan of the set used in the shot the next step is to track 2d point on the footage a tracking point can be anything from a rock on the ground to a tracking marker on a green screen the key is that point is small high contrast and stays in the same position throughout the shot depending on the level of parallax in your footage it may be required to track separte points for the foreground mid-ground and background for the tracking software to get a complete picture of your camera’s position relative to its environment once the points are tracked that data is used to calculate a motion path for the camera to follow if you have the lidar available you can then project the points onto the lidar to get a more accurate camera solve and to line up the 3d model of the set with the camera otherwise you’ll likely want to create some rough proxy models of the set yourself to get an idea of where objects lie in the scene with a good camera solved your 3d models will look like they actually exist in the footage provided that the model doesn’t suck or the textures and the shading and lighting etc.
object tracking on the other hand as the name suggest is the process of tracking object within the footage as opposed to the camera object tracks are used to replace or enhance an object that already exists in the footage there multiple reasons for it let’s say the element needs magical effects on it or if it needs to be extended or enhanced in any way by tracking an object we’re able to fool the viewer’s eye by closely matching the object’s motion or even track a nearby object match movement last but definitely not least the process of roto animation this task poses a unique challenge that demands patience skill and proper plan rotoanim is used most of the time to match the exact movement of a subject’s head hands feet and many times of the full body roto- anim could be needed for something as simple as gunshot wounds that need to be cheated because we obviously can’t shoot actors or it could be used for something extreme like matching the actor’s body movement in every single shot in order to replace the costumes or entirely transform them into human animal hybrids.