November/December 2014

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65 NOV-DEC 14 / CINEMONTAGE 65 NOV-DEC 14 / CINEMONTAGE TECH TIPS PLANAR TRACKING As previously mentioned, what makes mocha so powerful is that unlike After Effects — which contains a point tracker (it will track a single point in your shot, or two points if you are tracking rotation) — mocha is a planar tracker. What that means is that mocha Pro tracks and analyzes an area, or pattern, of pixels and derives a plane from it. If the plane is mostly moving in two dimensions, you can tell the software to limit the track to translation, scale, rotation and shear. For more complicated tracks, including three-dimensional movements, you can add perspective. One nice thing about tracking in mocha Pro is that you can change the tracking data as you go along. For example, let's say you are tracking the floor in a scene and at some point the part of the ground you are tracking moves out of frame. No need to start over; simply move the area you are tracking to another suitable position on the ground and continue. When you are done with tracking and rotoscoping, you can export the tracking or shape data from mocha Pro into a variety of different programs where it can be used. These programs include Adobe After Effects, NUKE, Flame, Quantel, Fusion and Adobe Premiere Pro. In the case of After Effects, if you export the shape data, you can simply paste it onto a layer by choosing Paste mocha Mask in the Edit menu. The result is an identical AE mask on the layer, with keys on every frame that cause it to perform precisely as it did in mocha Pro. If you're not after the mask, but rather the tracking data, you can export it from mocha Pro and paste it onto a layer in After Effects. This results in position, scale and rotation keyframes that cause the layer to move in the same way as the tracked object. If you'd rather render out an image sequence or QuickTime movie to be used as a matte in your compositing program, you can do that as well, and include things like motion blur and per vertex feathering. OTHER COMPELLING FEATURES Another great feature in mocha Pro is the Remove Tool. This handy feature is incredibly useful for rig and wire removal, as well as removing things like imperfections, blemishes, microphones — or even entire objects or actors. By creating a "garbage matte" around an object you want to remove, mocha will analyze the background and magically remove it from the scene. If there is not enough clean background in the shot for it to work its magic, you can provide your own clean plate for the purpose. This is an important and useful tool that can save many hours of work. Imagineer's mocha Pro can also analyze a scene and solve for a 3D camera, which it can export to other applications such as After Effects, CINEMA 4D, NUKE, Maya and other software. The Camera Solver is a useful feature; however, such programs as After Effects, C4D and NUKE have capable motion trackers built in. But if you don't use those packages, mocha Pro's Camera Solver should be useful. Lens distortion can sometimes present a problem when working with a scene shot with a wide lens that has caused a bulging effect in the image. The Lens Tab in mocha Pro has tools that can rectify lens distortion and straighten things out. You can also track a plane with the lens distortion as is, and export a distortion map for later use in compositing. Imagineer also provides a free lens effect plug- in for use in After Effects. Figure 2: mocha uses an X-Splines to create shapes (red line) with an innovative perpendicular control (in blue) that you can slide to sharpen or smooth out the points. There is also the option to use Bezier curves, as found in programs like Illustrator and Photoshop.

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