A VFX Company in Bristol

Rotoscoping is a labour intensive process involving tracing a particular object or region within the original footage frame by frame. Its name dates back to the traditional methods of hand drawn animation, but is more commonly used in the digital effects world as the process of creating an animate mask shape to be used as a matte. This matte can then be used to extract the traced objects, so that they can be manipulated as a completely separate element from the rest of the footage.

By cutting out an object, rotoscoping generally performs a similar result to chroma keying, just involving a more manual method because the original footage does not contain an easily removable background such as a green screen. Being such a time consuming process, larger projects are often farmed out to countries with cheaper labour costs. However, by using the latest cutting edge software, rotoscoping tools have become more automated allowing much quicker turnaround than just a few years ago.

Once a matte has been created, using various methods such as keying and/or rotoscoping, the resulting blank areas on screen need to be filled. Often this is performed using a matte painting, a 2d image created to give the illusion of the environment within the frame. This technique of set design dates back to the early days of film, when they used large hand painted backdrops behind the actors. Not dissimilar to what you may see in theatre set designs, which use decorated assets to help the audience comprehend the stage location.

In film, the concept is identical, although requires more detail to convince the viewer of the digitally modified environment. There are also added complications due to moving cameras and colour matching the matte painting to the film footage. Generally speaking, creating the desired effect becomes easier when the matte painted elements are further in the distance. Foreground elements are much more susceptible to inconsistent camera movement and lighting changes, and are therefore a tougher illusion to achieve. With the use of new 3d camera tracking technology, it is possible to create elaborate and believable digital environments which move with the camera, helping sell the illusion.

Tracking is an automated process, whereby the special effects software follows particular pixels on screen to create a motion path over time. This track can be performed on a moving object, if an effect needs to follow something in shot, or on multiple static scene objects, if the original camera movements need to be replicated. Tracks can be performed on a 2d plane, as well as in a full 3d environment, the latter requiring camera information and knowledge of the ground plane to help construct accurate 3d tracking information.

Careful consideration is needed when selecting specific groups of pixels to track, as certain footage may simply not produce accurate results. In particular circumstances, a vfx supervisor will add additional tracking points into the shot, which would then be removed in post using techniques such as rotoscoping.

Motion capture, is the name associated to tracking points attached to an actor’s body or face, whereby each tracked point creates a separate 3d motion path which in turn drives the animation of a rigged object or character. Most notably used within the movie industry to bring creatures to life by capturing data from professional actors’ movements. This technology operates in a similar way to 3d motion tracking, but requires additional camera equipment to help capture the points from all angles. There are various methods and hardware associated with motion capture, varying in quality and price. Thanks to our trusted partner Nymbl, we have access to a cost effective motion capture suite within their studio. We can therefore offer motion capture within our productions, which can be a huge timesaving process as well as creating much more realistic results.

This broad title covers both dynamic simulations such as fluids or collisions as well as more bespoke simulations such as crowd generators that may be used to produce the illusion of a large army. Either way, simulations use physics-based algorithms to create the desired effect and will often cross over into the field of 3d animation.

Popular plugins have been created for vfx software packages to help automate various simulations. These plugins can be used to create a range of results, as well as being used for more artistic effects that do not necessarily fit a specific story line. The output created from these simulations will be calculated from a number of properties and variables, including some randomly generated values to help form more natural movements. When creating less linear and more artistic productions, the values of these properties may also be driven by external inputs such as audio levels or motion capture data. This imaginative approach can produce some beautiful results, such as ink dancing to music or a burning fire being controlled by a dancer’s movements.

Simulations are extremely powerful ways of creating visual effects whilst retaining the ability to control individual attributes associated to the final outcome. Similar effects caught on camera would not offer this additional flexibility, such as freezing time mid explosion whilst the camera spins around to continue the explosion from a new camera angle. However, depending on the specific shot requirements, film footage may be a more cost effective approach, especially if purchased from a stock site. Therefore, although restricted, compositing filmed simulations into the footage should always be considered as a potential option.