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Tune Out Distractions

Tracking will be perturbed or lost if there are other, unmodeled, items in the imagery. For example,

- an actor may walk by,

- there may be fingers holding an object, or

- a tree or pole may temporarily occlude the object(s) being tracked.

The SynthEyes GeoH tracker will automatically take into account occlusions between 3-D objects in its 3-D workspace, whether they are being tracked or not. So if you're tracking an actress's body and arms, you don't have to worry too much about the actress's arm going in front of her body, as long as enough of the body remains to be tracked.

In some circumstances, you may be able to take advantage of that capability by adding "blocking meshes" into the scene, for example, a simple cylinder to represent a phone pole that goes by. That's especially true if the shot is camera-tracked, in addition to the GeoH tracking that you are doing.

Note : be aware of all meshes in your SynthEyes scene, so that they don't inadvertently serve as blockers. Also, be aware that they do impose some computational delay, especially if they have hundreds of thousands or millions of facets. In that case you may want to hide them during tracking, if they aren't doing something useful.

For fingers, swaying hair, or other minor issues surrounding or on the mesh you want to track, you can paint out that portion of the mesh, so it won't be tracked, by painting the base (parent-most) GeoH object.

For other objects, you might use the SynthEyes Roto (rotoscoping) panel to create a quick approximate animated garbage mask. The roto capability is designed for doing something quick and approximate, not for tracking specific fine edges.

Intro Version . The SynthEyes Intro version does not use roto garbage mattes or alpha channels as inputs to GeoH Tracking.

Warning : The “Invert” button on the Roto Masking panel is not supported by Planar Tracking. Inverted layers are treated as if they are not inverted. In all known cases, a spline stack containing inversion can be converted to an equivalent version that does not use inversion (and it’s usually simpler).

If you can set up a quick animated matte in some other package, you can import it as an alpha channel matte to SynthEyes as well. Once you do that, set the Alpha channel dropdown on the GeoH panel appropriately for the polarity of your matte.

For both roto and alpha mattes, see "Rotoscoping and Alpha Channel Mattes" in the SynthEyes user manual.

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