November/December 2014

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64 CINEMONTAGE / NOV-DEC 14 64 CINEMONTAGE / NOV-DEC 14 TECH TIPS by Joseph Herman I magineer Systems has recently released version 4 of mocha Pro, its highly regarded software for visual effects that is used by leading studios around the world. It has been used in the creation of such blockbuster motion pictures as The Hobbit, Black Swan, The Amazing Spiderman, the Harry Potter series and others. In February 2013, Imagineer was honored by the Academy of Motion Pictures Arts and Sciences with a Scientific and Technical Award for mocha's innovations, which have caused it to gain widespread adoption in the visual effects industry. The fact that it won this prestigious award should clue you in to the fact that mocha Pro is an important and compelling piece of software with impressive capabilities — especially in the areas of rotoscoping and planar tracking (see Figure 1)…as well as a whole lot more. Rotoscoping, of course, is the process of isolating objects in a scene over a series of frames. For example, you may wish to isolate a building in a scene to change its color. Or you might want to cut out a vehicle in order to lay it onto another background plate. Whatever the case might be, there are a million and one reasons to roto something, and it is a common task in many large productions. However, rotoscoping can be an extremely fussy and tedious process without the right tools. Programs such as After Effects might have built-in tools that allow for the rotoscoping of objects; however, they fall far short of the roto tools found in mocha Pro. The main reason mocha is so powerful is because it is a planar tracker as opposed to a point tracker. Planar tracking tracks the movement of planes in your scene, whether the planes are moving in two dimensions (horizontally and vertically) or in three dimensions (with perspective). This is incredibly useful in a wide variety of shots in which you might want to add images to television screens and computer monitors, or create those kind of slick- looking graphical interfaces that were first made popular in Steven Spielberg's 2002 film Minority Report and can be seen in many other movies such as the Iron Man series. The list of uses for planar tracking range from plastering billboards and signs to walls to placing advertisements on the sides of buses to adding logos to the front of a book. However, planar tracking is also very useful in — and complementary to — rotoscoping. You can track a plane, such as the surface of a wall, and then create roto shapes for paintings on that wall. Next, you can link the roto shapes to the planar track, which causes them to automatically move in conjunction with the plane. If the linked roto masks happen to drift a bit during the shot, they can easily be fixed with a few judicious key frames here and there (see Figure 2). By linking roto masks to a planar track, the process of rotoscoping becomes much easier than trying to rotoscope objects manually, frame by frame. Of course, this saves you a lot of time and frustration. If you have never used mocha before and are accustomed to doing manual roto work, once you do it this way, you'll never look back. mocha Machine IMAGINEER SYSTEMS PERKS UP VFX WORK Figure 1: mocha Pro 4 is a robust planar tracking and rotoscoping tool. It is also capable of many things such as object removal, camera solving stabilization and more and is an important tool for many visual effects studios.

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