Wednesday, December 26, 2007

Sangita Sharma Phukan

Compositing may be defined as combining multiple images to create a single image. In visual effects post-production, compositing refers to creating complex images or moving images by combining images from different sources—such as real-world digital video, digitised film, synthetic 3-D imagery, 2-D animations, painted backdrops, digital still photographs, and text.

Elements of compositing

The main elements of compositing consist of selections, copy and paste operations, and positioning of image elements. In particular, we are usually attempting to produce (sequences of) images which could have been believably photographed without the use of any post-processing. Colloquially, it should look ‘real.’ Even if the elements in the scene are obviously not real, (huge insects living inside a giant peach, for example), one must be able to believe that everything in the scene was photographed at the same time, by the same camera.

Job profile

Today, compositing involves the use of computers. Movies are generally shot on 35 mm film. For compositing, the film has to be digitised with a film scanner. It is then transferred to a computer where it can be edited. The compositors gather all material they need for a scene and then combine the different clips to achieve the result that they need. A technique that greatly facilitates compositing is a blue screen where an object or actor is filmed in front of a solid color screen, usually colored blue or green. During compositing, all areas of a frame with that colour are removed which allows the compositor to place the object or actor in front of a new background.

"Compositing can be understood as the process of combining visual elements from separate sources into single images that gives the illusion of parts of the same scene. Live-action shooting for compositing is referred to as "blue screen", "green screen," "chroma key" and other names. This means that the live character is shot with a chroma background which is removed for compositing other elements," explains R.Krishnan, global head, Arena Animation.

Software used

Combustion 4.0 is a software for motion graphics, compositing and visual effects. Combustion 4.0, with its easy-to-use interface, non-destructive workflow and extensive toolset, delivers incredible power and augments the creative potential of any desktop video artist. Combustion 4.0 features a complete set of sophisticated tools for visual effects creation, including vector paint, particles, effects, animation and 3-D compositing tools.

Key features and capabilities of Combustion 4 include:

  • Powerful creative tools:Combustion 4.0 provides in-context access to motion graphics, industry-leading 3D compositing, colour correction, image stabilisation, vector paint and roto, text effects, short-form editing, expressions, Flash® output, and much more.

  • Artist-friendly interface: Combustion 4.0 features Autodesk Media and Entertainment’s unified and easy-to-use interface, including multiple-screen, in-context design work; easy navigation; and a schematic node based view—all designed to get you to your destination quicker and easier.

  • Broad interoperability: Combustion 4 delivers unmatched integration with industry-standard 3D animation, imaging, and illustration software, including Autodesk’s leading 3ds Max® animation software, Autodesk® Cleaner® encoding software, and Discreet® Flint®, Discreet® Flame®, Discreet® Inferno®, Discreet® Fire®, and Discreet® Smoke® systems products.

Work tools

  • Diamond Keyer: Sophisticated keying algorithms derived from Discreet® Flame ®, Autodesk Media and Entertainment’s Academy Award®-winning online visual effects system.

  • Time-Warp:a fully key-frame-able, time-remapping operator for quickly creating slow-motion and speed-up effects.

  • B-spline vector shapes and new point-grouping-faster, more efficient rotoscoping.

  • New optimised ‘Fast Gaussian Blur’

  • Custom capsules: create and save encapsulated single or grouped operator nodes and build yourself a library of effects to share and re-use

  • Gbuffer builder: enables custom building of Discreet’s Rich Pixel Format (RPF) data structures from bitmap files for more extensive use of Combustion RPF nodes

  • Merge operator: new optimised operator to quickly merge two layers of the same size using any Combustion transfer node

  • Interface enhancements: edit-operator, navigation, filtering, and compare-tool improvements, just to name a few.

  • New file import/export options-import of images into color mixer, import ASE (ASCII Scene Export) camera targets from Autodesk® 3ds Max software, import Windows Media®, OpenEXR-compatible output

  • Enhanced paint:new paint tools, grids and rulers, B-spline in paint, and new customized brushes

Demand for compositing professionals

Compositing is here to stay in the multimedia industry, whether it is in films, videos, commercials or any other field. The PWC report on entertainment and media practice forecasts that the global industry revenues are set to increase from $ 1.2 trillion in 2003 to $ 1.7 trillion in 2008, a 6.3 per cent CAGR.

"There is a dire need for artistic skills to complement the technical skills required for visual effects, which can only be brought about by adequate training. Once both the artistic skills and technical training come together, visual effects will merge seamlessly with the movie and flow as part of the script," adds Krishnan.