There Are No Point Trackers
In mocha splines are used for both tracking and rotoscoping. This is a different method from standard
1-point or multi-point tracking tools.
Traditional tracking tools require that you locate “points” that remain consistent throughout the entire
shot in order to track movement. This is itself a difficult task, especially when tracking a shot that
was not originally designed to be tracked. If you wish to also track rotation, perspective and shear you
need even more clear and consistent points to track.
Traditional roto methodology would have you outline a shape with the minimum number of points
necessary then either manually move the control points or track the shape with a point tracker to “get it
close”. Even when using multi-point trackers to impart rotation and scale to the roto spline, the results
are often unusable if there is any perspective change during the shot.
Instead, Imagineer’s Planar Tracker tracks an object’s translation, rotation and scaling data based on
the movement of a user-defined plane.
A plane is any flat surface having only two dimensions, such as a table top, a wall, or a television
screen. Planes provide much more detail to the computer about an object’s translation, rotation and
scaling than is possible with point-based tracking tools. Even as an object leaves and enters a frame,
there is usually enough information for the Planar Tracker to maintain a solid track of the object.
When you work with the mocha tools, you will need to look for planes in the clip. More specifically,
you will need to look for planes that coincide with movements you want to track. If someone is waving
goodbye, you can break their arm into two planes - the upper and lower limbs. Although not all of
the points on the arm sections actually lie on the same two-dimensional surface, the apparent parallax
will be minimal.

New features in mocha 3.0.0
mocha 3.0.0; contains new functionality and major changes to workflow.
Introduction 17 December 2012
2
New features include:
• New layer tree system
• Ability to Customize color for both mattes and splines
• Project merging
• Bounding boxes for splines
• Multi-spline selection and modification
• Layer groups
• 3D camera solver for After Effects and FBX Export
• Dope sheet for key manipulation
• Enhanced link tool to join points of separate layers
• Zooming into footage now shows individual pixels

To quickly get familiar with mocha before you dive into the rest of the manual, here is a breakdown
of the interface and its controls.
Note: Interface Overview uses mocha Pro Interface. Mocha, mocha for After Effects and mocha for
Final Cut may differ in presentation, but their tools perform the same function

Stabilizing Shaky Camera Footage
One of the most common reasons to stabilize is to remove jitter from a shaky camera shot. With shaky
camera footage you are primarily concerned with removing position and rotation data. This means
you do not have to use the shear or perspective options when tracking. Here is the common method:
1. Track a static area of the shot using Translation, Scale and Rotation only. You don’t want to track
a moving object within the shot as this will throw off the stabilization.
2. Once tracked, switch to the Stabilization tool.
3. Choose which fields of motion you wish to stabilize in the Smooth parameters. By default, translation
is automatically selected. In many cases you may only be interested in position stabilization,
but hand-held cameras can introduce scale and rotation jitter as well.
4. Adjust the number of frames you want to look for jitter over. A small amount of frames will look
for tiny adjustments in the overall motion, whereas bigger values in this field will adjust larger
ranges of motion.

5. If there is a significant amount of motion being stabilized and you are losing a lot of your picture
in some frames, try fixing those frames by adding them to the Frame List on the left. Mocha will
then interpolate the stabilization between these fixed frames

Locking Down Areas of Motion
Sometimes you want to be able to completely lock down a section of the footage so that it stays in one
place and everything else moves around it. For this you can use more aggressive stabilization:
1. Track the area you want to lock down using whichever of the motion parameters you require.
Tracking perspective also works for this technique.
2. Once tracked, switch to the Stabilization tool.
3. Choose which fields of motion you wish to lock down in the Smooth parameters. By default, translation
is automatically selected. If you want to completely lock down everything, just choose the
“All Motion” checkbox.
4. Adjust the number of frames you want to use to look for stablisation. A small amount of frames
will look for tiny adjustments in the overall motion, whereas bigger values in this field will adjust
larger ranges of motion. Again, if you want to completely lock down everything for all motion,
choose the “Maximum Smoothing” option.
5. When you play back the timeline you will see the rest of the footage warp and move around your
locked off area.

Most often a good matte requires a combination of both keying and rotoscoping techniques.
Good rotoscoping artists often think like animators, reverse engineering the movements, the easing in
and outs, the holds and overshoots of objects, and set their keyframes accordingly.
In general, the fewer the keyframes, the better your mattes will look. Too many keyframes will cause
the edges to “chatter” and move unnaturally. Too few keyframes will cause the shapes to drift and
lose definition. Finding the right number and placement of keyframes often comes with experience
but there are a few things to keep in mind when rotoscoping.

Traditional Roto Tips
1. There is no such thing as a perfect matte. Rotoscoping is an art form that takes into account the
background image, the movement of the object, and the new elements to be composited in the
background.
2. Try to start your shape at its most complex point in time, where it will need the most control points.
3. Break a complex shape into multiple simple shapes. If you are rotoscoping a humanoid form and
an arm becomes visible, consider rotoscoping the arm as its own element, rather than adding extra
points on the body that will serve no purpose when the arm is obscured.
4. Imagine you are the animator who created the shot. What would your dope sheet look like? No
matter the medium, whether CG, live action or otherwise, most movements are rarely linear.
They normally move in arcs; they normally accelerate in and out of stopped positions. Try and
understand the mechanics behind how things are moving in your shot. This will help you to
minimize keyframes.
5. Watch and study the shot before you start working. Where are the changes in directions? These
will normally have keyframes. Where are the starts and stops? Are there camera moves that can
be stabilized to make your work easier?
6. Don’t be afraid to trash your work and start over. Beginning roto artists often make the mistake
of trying to fix a flawed approach by adding more and more keyframes. Experienced roto artists
learn to quickly identify an inferior approach and are unashamed to trash their work and start over,
often many, many times. It is very difficult to get a good matte without a conscious effort to keep
the keyframes to a minimum.

Mocha Tracking and Roto
While you can refine a shape you have tracked to do your rotoscoping, the recommended way is to
do a rough shape to track something and then link your roto to that track. This reduces the amount
of work required when you are dealing with complex shapes, as you will not have to track and refine
each shape as you go. It also means that if you have to retrack something you won’t have to redo a lot
of layers. Another reason is reducing the amount of data needed in your project file.
It also helps to remember that your spline shape is linked to your tracking data and not the other way
around.
For the following examples you can try out the tools using the BMW tutorial files available from http://
http://www.imagineersystems.com/videos/clips/rotoscoping.zip

Rotoscoping Workflow
1. Track the area you want to rotoscope
First of all you want to reduce as much manual work as possible by tracking. In the example below,
the front and side plane of the car is being tracked (For a more detailed coverage of tracking, see the
Tracking Basics documentation).
2. Turn off your tracking shape
Once you’ve tracked an area it can be useful to turn it’s visibility off, as well as it’s tracking cog (so
it can’t be accidentally retracked later). This means the tracked shape will not be confused with any
roto shapes you are making.
3. Start drawing your refined shapes
Once you have a track for a layer we recommend that you add a new layer to use for the actual roto
spline, rather than refining the spline you used for the actual track as you might need to do more
tracking with it later.
Select the X spline or Bézier spline tool and draw a tight spline around the object you are rotoscoping.
Ctrl/Cmd+drag the Bézier tangents if you wish to break them. You will see that a new layer is
automatically created.

4. Link the new roto layer to your tracked layer
You don’t want to track with this layer, so disable tracking for the layer by turning off the tracking
button (the cog) for the layer in the Layer Properties panel.
Rename the new layer and link it to the movement of your already tracked layer by selecting it from
the “Link to Track” dropdown in the layer properties panel.
Your newly created roto spline will now follow the motion of the linked track.

5. Refine your roto
Now you have linked the rotoscoping layer to a track, you need to go over the timeline and make sure
the roto is correctly animated.
Often you will need to tweak your shape for it to fit correctly, adding new keyframes. Autokey is on by
default, so you just need to move along the timeline and adjust your points where necessary (keyframes
turn up in the timeline as green dots). The tracking data will help for the majority of the motion.
You can also add additional shapes to the same layer using one of the "Add Spline to Layer" tools.
These are the drawing icons with the plus sign next to them ("+").

You can also use the Set button under Edge Properties to feather the edge at the selected point(s) an
exact amount or use the Add button to increase/decrease the feather by the specified amount.
For example, if you deselect all points by clicking anywhere on the canvas you can then use the Set
button to apply the default 3 pixel edge width. Because no points are selected the value is applied to
all points on the current layer. You can then tweak the position of all spline points to ensure that the
inner (red) spline is inside the edge and the outer (blue) spline is outside the edge.
7. Track additional sections as you go
In many instances one track will not be enough. You may need to track more than one plane to drive
different sets of roto. In the car example, we have to track the front and the side to get an accurate
track for each planar region to assist the roto effectively.
In the case of organic shapes, like people, you will have to break your tracks down to handle the
different movement between the torso and the arms etc.

What’s the Überkey?
The Überkey is a powerful tool that allows you to offset the positions of control points without
destroying their keyframe data.
Use this tool with care, as it is not setting any keyframes per se, it is offsetting any and all keyframe
data on the points you move while it is on. Überkey is very useful, but remember to turn it off again
when you don’t need it. Use with care.
Überkey affects only those frames between the timeline's In and Out point. If you wish to make
adjustments to a particular range, set the In and Out points to that range.

Turning On and Off Points
You can turn on and off individual points in a spline. When they are off, you can still see the points,
they can still be animated, but they are not contributing mathematically to the spline. This allows you
to have a complex spline only when you need it, rather than having to deal with superfluous points
in parts of the shot when they are not needed.
To turn off points, select the points on the spline and hit Shift+Delete. You will see the curve change
shapes, but the points will remain.
To turn a point back on, right-click on it and select Point->Activate.
If the Autokey button is enabled, a keyframe will be created when you change a point’s active status.