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Home School of Communications, Media, Arts and Design Blog 2015 November 24 Movies exposed: Secrets of digital visual effects

Movies exposed: Secrets of digital visual effects

picture of a centennial college digital visual effects program student working on a digital effect in the computer lab

Have you ever been so absolutely blown away by a movie because of how incredibly life-like it was? And that the only thing giving it away as “just a movie” was the fact that it was based in a world that doesn’t exist? These days, you’re pretty safe to assume that a lot of what you see on the big-screen is the work of computer-generated imagery. But achieving such spectacular scenes, like those in Alice in Wonderland, Pirates of the Caribbean and Game of Thrones, doesn’t happen overnight. In fact, sometimes getting a single scene perfect (one that lasts mere seconds) can take months to finish. So how do they do it? You can learn all this and more in Centennial’s Digital Visual Effects program (the only two-year diploma program of its kind in Ontario). Below we draw the curtain on just a few of the industry’s secrets.


Simply put, compositing in digital visual effects means to combine multiple objects (images, video or other artwork) into a single picture. It’s like building a house – combining the necessary materials together (bricks, shingles, nails, etc.) to construct the final product. Using a technique called chroma keying, which usually incorporates a green or blue screen, compositors (the builders) will take live-shot footage and replace the green or blue colour with a computer-generated element. Whether it’s a graphic or another piece of footage, the goal is to be able to blend them seamlessly as if it were a single shot. You’ve most likely seen compositing during weather forecasts on TV in which footage of the meteorologist and digital weather maps are combined. This makes it look as if the forecast is being done in front of the maps (when they’re really standing in front of a green screen). Movies and television use compositing extensively. From the passing scenery out the windows of a moving car to being able to have Godzilla stalk through major cities in Japan, compositing is an essential part of filmmaking.

Matte Painting and Set Extension

One of the oldest and most common visual effects techniques is matte painting, which allows a director to go beyond the confines of studio walls by compositing painted images with previously filmed footage. Digital visual effects courses in Toronto will teach you that these paintings are used in the creation of scenes that require enhancement (like adding buildings that aren’t in the original shot), or creating worlds that don’t exist (like Maleficent’s forest of thorns). In the past, mattes were actually painted on large panes of glass and footage was then projected through the unpainted, translucent spots. Mattes can also make a scene look bigger and provide greater depth of field in what is known as set extension. A classic example of this can be seen in the Wizard of Oz in which the yellow brick road in the physical set meets with a painted backdrop of the yellow brick road leading to the Emerald City in the far-off distance. Today, matte paintings are created digitally, using computer software that works in conjunction with graphic tablets and specialized stylus pens. Artists are also able to 3D map painted images so they can become part of a moving scene, making them even more realistic.


In any digital effects program in Toronto, you’ll quickly learn that in order to create a film that simulates reality, a huge number of special ingredients are necessary. In post-production, features like shading, texturing, bump mapping and reflection are added to all composited pieces in order to finalize the film and make it appear as seamless and as real as possible. And because there are so many pieces that come together, and so much information about each item, it can take a long time to process (or render). To help illustrate just how big these files can be, Blue Sky Studios (the people behind the Ice Age series) say a movie that’s completely digital consists of 24 images per second with each image containing approximately two million pixels. In a two-hour movie, that’s 345.6 million pixels! That’s an enormous amount of data to process. Your typical desktop computer would probably go up in flames trying to render a file this large, so that’s where “render farms” come into play. These bad boys are a collection of rack-mounted multi-processors, able to perform and solve a number of complex equations, averaging between two and four hours per frame, that eventually turn the right ingredients into the finished product.

So if you love movies and are artistically inclined, then you should really consider getting a digital visual effects diploma in Toronto. It was pretty much made for you. Applications for September 2016 are open now!

By Ashley Breedon