Mocha AE CC Plug-in V6.0.0 User Guide

Tracking and rotoscoping are part of almost any visual effects project. For 2D tracking, point trackers are most commonly used, but to get good point tracks requires a mix of experience and luck. You often have to “prime” a clip for optimum tracking using color correctors and other image manipulations. If the point being tracked exits frame, you get into offset tracking, which presents its own set of challenges. If it all fails, you are into hand tracking, which is time consuming and very hard to get accurate.

Mocha is a 2D tracker that requires less experience and luck to be successful with, does not require the image to be primed and is less likely to require a lot of tricks or hand tracking on difficult shots.

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.

Mocha layouts are modifiable, allowing you to hide or reveal many parts of the interface.

These layouts are clustered into 4 default types you can build from.

You can add or remove many parts of the Mocha interface, such as:

These can either be access by right clicking the area of the interface and choosing a GUI element to show or hide, or selecting from the View menu.

Any changes you make to a layout will not be saved unless you choose View | Layout | Save Current Layout.

For example if you like the Essentials layout, but would like the Advanced toolbar from the Classic layout:

This will now save the Essentials layout with the new toolbar.

If you have made changes to a saved layout want to revert back to the saved version, just choose View | Layout | Revert to saved.

If you want to revert back to the original default layout, just choose View | Layout | Revert to default.

At the very top of the interface you have the tools that form the brunt of your time inside Mocha.

In Essentials Mode, only a basic set of tools are shown, to simplify the interface.

The only tools shown here are:

See descriptions in Advanced Toolbar above for the rest of the tools.

These controls cover what can been seen or hidden while working in the Mocha viewer.

The timeline controls cover frame range, playback, tracking controls and key-framing.

The top left hand panel contains the tools to manage layers.

The section under the Layer Controls panel contains the properties for each layer.

In Mocha v5 we introduced manual cache clearing to allow you to clear the Mocha cache at the project, render or global level.

You can access the Clear Cache option from the file menu under File → Clear Cache…​

You can check the following options:

Only clear the Global Cache if you are certain you don’t want any of your existing project caches to remain.

The Mocha AE CC Plugin for Adobe appears in the Effects menu like every other effect.
Simply apply the effect to the layer you want to work with.

The general workflow for the Mocha Adobe Plugin is as follows:

Imagineer’s Planar Tracker technology provides 2D tracking data by tracking planes rather than points.

The key to getting the most out of the Planar Tracker is to learn to find planes of movement in your shot which coincide with the object that you want to track or roto. Sometimes it will be obvious - other times you may have to break your object into different planes of movement. For instance if you were tracking a tabletop, you would want to draw the spline to avoid the flower arrangement in the center of the table — it is not on the same plane and will make your track less accurate.

To select a plane you simply draw a spline around it. You can be fairly loose with your spline — the Planar Tracker is intelligent enough to discard the pixel movement that doesn’t conform to the movement of the majority of the pixels within the shape.

Mocha features two spline types, X-Splines and Bézier splines:

One of the most important concepts to understand with the Mocha planar tracking system is that the spline movement is not the tracking data.

It’s best to think of the splines you draw around objects as search areas. Here’s a breakdown of how the tracking works:

To see this relationship, turn on your surface and/or grid in the viewer after you have tracked something. Scrub the timeline and you will see that the grid and surface move with the spline.

Now select all the points of your spline and move it around the viewer. You will notice that the surface/grid will stay in the same place.

This is because the spline is linked to the track, but the track is not linked to the spline. The spline is merely a search area to tell the track where to go next. It is a common misconception that moving the spline while tracking is affecting the movement of the tracking data. It is not. Moving the spline is only telling the tracker to look in a different place and will not directly affect the motion of the tracking.

This makes the tracker very powerful, as you can move and manipulate your spline area around while tracking to avoid problem areas or add more detail for the search.

You can even unlink the spline from the track entirely so that any planar surface passing under the stationary spline area is tracked and you don’t have to move the spline if tracking starts to go off screen.

With the Planar Tracker you simply draw a spline around something, as shown with the screen below.

In some cases there are parts of an image that can interfere with the effectiveness of the Planar Tracker. To handle this, you can create an exclusion zone in the area you are tracking.

For instance, in the phone example we are using, there are frames where there are strong reflections on the screen. These reflections can make the track jump. So we need to isolate that area so the tracker ignores it. Here’s how this is done:

You can also add as many entirely new layers on top of your tracking layer to mask out the layers below.

This is quite common when moving people, limbs, cars, badgers etc. get in front of the object you are trying to track.

In the Essentials layout, tracking Motion parameters are listed in the Essentials Panel:

In the Classic layout, detailed tracking parameters can be accessed by selecting the Track tab. On the left hand side of the Track tab, you will see two sections: Motion and Search Area.

Understanding the parameters section of the Track parameters is vitally important for obtaining good tracks. Here we provide a breakdown of each parameter and how to use it effectively.

Input Clip

This is the clip you are going to track. By default it is the one currently in the viewer.

Input Channel

When tracking, Mocha looks at contrast for detail. The input channel determines where to look for that contrast.
. Luminance looks for contrast in the light and dark of the image
. Auto Channel looks for contrast in one of the color channels.

By default, Luminance does a good job. If you have low-luminance footage or you are not getting a good track, try Auto Channel.

Min % Pixels Used

One of the most important parameters to look at for tracking.

By default, the minimum percentage of pixels used is dynamic. When you draw a shape, Mocha tries to determine the optimal amount of pixels to look for in order to speed up tracking. If you draw a very large shape, the percentage will be low. If you draw a small shape, the percentage will be high.

In many cases, the cause of a drifting or slipping track is a low percentage of pixels. If you want a more solid and accurate track, try setting the Min % Pixels Used value to a higher amount. Keep in mind however that a larger percentage of pixels can mean a slower track.

Smoothing Level

This value blurs the input clip before it is tracked. This can be useful when there is a lot of severe noise in the clip. It is left at zero by default.

Motion

These parameters control what motion you are looking for when you track:

The main difference between shear and perspective is the relative motion. Shear is defined as the object warping in only two corners, whereas perspective is most often needed where the object is rotating away from the viewer significantly in space.

As an example, if someone is walking towards you, their torso would be showing shear as it rotates slightly back and forth from your point of view.

The front of a truck turning a corner in front of you would be showing significant perspective change.

Search Area

This defines ranges for the tracker to search within

Before performing the actual track, adjust the settings depending on the movement in the clip.

Track the plane selected by pressing the Track Forwards button on the right- hand side of the transport controls section.

Stop the track and adjust the shape if it doesn’t seem to be tracking properly. You may keyframe the spline shape so that it tracks only the planar region of a shape by adjusting the shape and hitting Add Key in the keyframe controls menu. Keep in mind that no initial keyframe is set until you first hit Add Key or move a point with Auto-Key turned on.

The spline should be tracked in addition to the clip being cached to RAM. You can play it back and get an idea as to how the track went. Feel free to change the playback mode in the transport controls to loop or ping-pong your track.

Another trick you can do to check your track is hit the Stabilize button in the View Controls.

Turning on Stabilize will lock the tracked item in place, moving the image to compensate. In the track module, stabilize view is a preview mode to check your track. Actual stabilization output is handled by the Stabilize Module, explained in the Stabilize Overview chapter.

You can check the accuracy of your planar track by turning on the Surface and Grid overlay in the View Control panel. Drag the corners of the Surface overlay (the dark blue rectangle) to match the perspective of your tracked plane. If you play the clip, you should see the surface or grid line up perfectly with the plane you tracked.

Next click on the Surface button under View Controls.

When you turn on the surface you will see the blue box that represents the 4 points of the corner-pin. Right now you will see that it is not lined up with the screen.

By selecting each corner one at a time you can adjust the surface area to cover the area of the screen.

The Grid overlay should line up with the plane you’re tracking and move with it as you cycle through the clip. You can change the density of the grid by adjusting the X and Y grid values in View | Viewer Preferences:

The grid overlay can give you a quick representation of the accuracy of the track.

The Trace feature allows you to see the position of the planar corners over time. Skip allows you to work with only every nth frame, useful on particularly long roto shots where the movement is predictable.

To monitor what the tracker "sees" as a tracking area, select the Track Matte button in the view control.

There may be instances where you have already created mattes for one or more objects in the shot, for example using a keyer or another roto tool that would help you isolate areas to track. You can import such mattes by creating a new layer and then using the Matte Clip setting under Layer Properties to assign it to the layer.

Scrub your timeline

When starting a new project, go through your footage a few times to see what your best options are for tracking. You will save yourself a lot of time by making note of obstructions and possible problem areas in advance.

Use edges

When tracking surfaces you will usually get a much better track if you include the edges and not just the interior of an object. This is because Mocha can define the difference between the background and the foreground and lock on better.

For example, if you are tracking a greenscreen, it is better to draw your shape around the entire screen rather than just the internal tracking markers. In some cases this means you can avoid tracking markers altogether and save time on cleanup later.

When in doubt, ramp up your pixels

You can quite often get a great result with default settings, but if you’re getting a lot of drift, try setting the Min % Pixels Used value higher. The processing can be slower, but you will usually get a much more solid track.

Draw more shapes

Remember you are not limited to one shape in a layer. Use a combination of shapes to add further areas or cut holes in existing areas to maximize your search. If necessary, make an additional layer to track and mask out foreground obstructions before tracking the object you need.

Use the grid while tracking

It’s common to use the surface and the grid to line up your corners after you track, but it can be much more advantageous to set up your surface before you track and leave the grid on to watch for any subtle drift while you are tracking. This way you can stop your track early to fix any issues and spend less time trying to find them later.

Track from the largest, clearest point

In order for Mocha to keep the best possible track, it is usually best to scrub through the timeline and find the largest and clearest area to begin tracking from, draw your shape there, then use backwards and forward tracking from that point.

For example, if you have a shot of sign coming toward you down a freeway, it is usually better to start at the end of the clip where the sign is largest, draw your shape and track backwards, rather than start from the beginning of the clip.

A planar surface does not necessarily have to be flat

We have a Planar Tracker which specifically tracks planes of motion, but this is not limited to tables, walls and other flat objects.

Distant background is considered flat by the camera where there is no parallax. Faces can be tracked very successfully around the eyes and bridge of the nose. Rocky ground, rumpled cushions, clumps of bushes, human torsos and curved car bodies are all good candidates. The key is low parallax or no obvious moving depth.

When in doubt, try quickly tracking an area to see if it will work, as you can quite often trick the planar tracker into thinking something is planar.

In the end, there is no magic bullet

Mocha is a very flexible tracker and will save a lot of time, but you will eventually run into a piece of footage that just will not track. Large or continuous obstructions, extreme blur, low contrast details and sudden flashes can all cause drift or untrackable situations.

If something just isn’t tracking no matter what you try, consider using Mocha to track as much as possible then move to manual work. You can often get a lot more done fixing shots by hand or using AdjustTrack in Mocha rather than trying to tweak your shapes and parameters over and over again to get everything done automatically.

There will be times when tracks can drift due to lack of detail or introduction of small obstructions.  When this occurs, manual refinements can be made by using the AdjustTrack tool.

AdjustTrack is primarily used for eradicating drift by utilizing the four-corner surface area to generate keyframable data to compensate.  It is generally not practical to use it to remove jitter.

To achieve an adjusted track you would ideally line up the surface area where you want to place your insert or lock down your roto. In situations where you don’t require an insertion you should place the corners of the surface area in distinctive locations, as you will need to refer to these locations when you add keyframes to correct the drift.

When you have the Surface where you want it to stay locked and are ready to refine the track, flip over into the AdjustTrack module by hitting the AdjustTrack tab.

Once you select the AdjustTrack tab, a key frame with four reference points is created.

As you play though the sequence you will be able to manually adjust the position of each point as drift occurs.

If your track is spot on, these reference points should line up properly throughout the shot. If you see a Reference Point drifting, that will indicate the track is drifting. Find the frame where the drift is worst and move the Reference Point back to the position it had in the Master Frame and the track will automatically be adjusted based on your correction.

When you perform an adjust track and you begin to move a newly created reference point, you will notice the dashed lines which connect all of the reference points. These lines change in color to represent the quality of positioning of any given reference point. For best results keep reference points away from one another.

When adjusting the track try to always get at least yellow but shoot for green for a more solid adjust track.

The red lines indicate that this reference point position is a poor choice.

The green lines indicate that this reference point position is a good choice.

Often there are times where your reference points are either obscured or exit frame. In AdjustTrack you have the ability to create multiple reference points per surface corner that can be positioned in alternate locations to handle these situations. Simply click the New Ref button to create a new reference point for the selected corner.

You cannot keyframe the Surface — only the Reference Points. The original track and any refinements you make in AdjustTrack cause the Surface to move however.

Every so often a shot will come along that is easier to track backwards than forwards. This is fairly simple when running the tracker backwards, but introduces some rather obtuse concepts when keyframing is involved. This is why there are two “New Ref” buttons provided. If you are working backwards and wish to set a new reference point, you will probably want to use the “<- New Ref” button instead of the forward-thinking “New Ref ->” button.

Because keyframing “thinks” forward, hitting “<-New Ref” will not create new Master Reference points on the current frame, but will go backwards in time, looking for any existing keyframes and set new Master Reference points on the frame directly after. For example, if you decide to create a new backwards reference point at frame 20, a new master reference will be created at frame 21.

Some people may be more comfortable doing this manually by moving the playhead themselves and using the traditional “New Ref ->” button. Others who do a lot of tracking and find themselves working backwards often may find the backwards-thinking New Ref button helpful.

Every Reference Point has one frame in which its initial placement is determined without causing any adjustment to the track. This is called the Master Reference Point; if you step forward or backward in time you will notice the red X change to a red dot.

The red X indicates that this particular frame is the starting point for calculating adjustments. Moving a Master Reference Point will NOT change the tracking data.

Go ahead and experiment - move the Reference Point when it is a red X (a Master Reference Point). You will notice the Surface isn’t adjusted at all. Step forward a frame and move the same point - this time the surface will move because you are now adjusting the track.

By default, the frame in which you create a Reference Point is its Master Reference frame. This Master Reference can occur on a different frame for each reference point. You can change the Master Reference frame by selecting a Reference Point, going to the appropriate frame and hitting the “Set Master” button.

You may set a new Master Reference Frame for all active points by hitting the Set Master All button.

One method for selecting different reference points is to hit the “Next” button.

The next button simply cycles through the active reference points for that frame. More fine-grained control of reference points can be obtained through the Nudge control panel, described below.

Deleting Reference Points is done by selecting the point you wish to remove and hitting the delete key. If there are multiple Reference points on a particular corner, the preceding Reference Point will be extended through your time line until a new Reference point is encountered.

The Nudge section allows you to move Reference points in 0.1 pixel increments, much more fine grained than would be possible by dragging the points manually. You can easily select any active Reference Point by selecting one of the corner buttons in the Nudge section.

If you hit the Auto button, a tracker will attempt to line up the selected Reference Point based on its position in the Master Reference frame. The Search Region Size and Maximum Motion parameters can be set in pixels in the Auto Nudge section.

You can quickly select any corner by using the Corner selector buttons in the Nudge control panel. In the image below, the user is selecting the upper right corner in preparation for nudging operations.

The AdjustTrack tab has a View section for cleaning up your AdjustTrack workspace. Deselecting the Inactive Traces button will cause the display to hide the traces of the inactive Reference Points. This is helpful if you have a corner with numerous Reference Points offsetting it.

Deselecting the Unselected Traces button will hide any Reference Point that is not selected.

Finally, deselecting the Search Area button will hide the Search Region Size (in Yellow) and the Maximum Motion search area (in Pink).

Adjust frames at the peak of drift

When you see a drift, carefully cycle through the timeline and look for where the motion starts to change direction. A frame before this, adjust your drift, then go halfway between your master frame and the adjusted frame to check for any further drift.  If you keep working by checking halfway between each keyframe you set, you will reduce the amount of keyframes required.

A huge amount of keyframes is not a good sign

If you end up with adjustment keyframes on a large amount of frames it may be better retry the track.  AdjustTrack is aimed to help reduce small anomalies and fix drift when a tracked corner has become obscured.  If you are fixing every second keyframe it means you have more than a simple drift.

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.

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://cdn.borisfx.com/borisfx/store/clips/rotoscoping.zip

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.

You can translate, rotate and scale selected points as a group by using the corresponding tools listed in the toolbar.

Or alternatively, use the transform tool to perform all of the above functions in the same tool:

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.

You can use the movement of the individual spline points to determine motion blur. Any movement in the spline, whether through simple X/Y translation or by shape deformation will cause motion blur.

You can control the amount of blur by changing the motion blur value in the Edge Properties panel.

Although not necessary in this example, note that you can change how mattes are blended in the Layer Properties panel. You may make each layer’s matte Add or Subtract and you can also invert the matte.

Note that this can’t be keyframed and that these settings apply to the entire layer, not to individual splines of the same layer.

In the View Controls, several options are offered for viewing your mattes. The Matte drop down is has options to view all mattes, just the mattes you have selected or no mattes.

Select the Matte button and you will see your rotoscoped object against a flat background.

You may wish to rotoscope against a particular color. Select View → Canvas Color…​ and a color picker will allow you to choose a particular background color

When you have your Mattes turned on, you may choose for the matte to be filled with a color instead of cutting out the object, using Colorize.

You can adjust the opacity of the color fill by changing the blend value to the right of the Colorize button.

The color used by Colorize is derived from the Selected and Unselected properties of the Overlay Colors panel, which can be changed per layer.

This is only a preview and will not affect how your mattes are rendered when exporting.

In the View Controls panel, you will find a drop-down menu for selecting the clip to view.

This allows you to view the actual rendered mattes, which can be especially useful when tweaking motion blur. The motion blur you normally see in your canvas is an OpenGL preview and can differ slightly from the actual render.

If you’d like to see what the actual motion blur render looks like, switch to viewing the layer whose matte you wish to see.

Because you can choose specific layers for export when you render, a render pass is created for each layer.

Switch the View Clip drop-down back to your source clip to continue working with that clip.

If you want to draw open splines, you can simply hold shift when you right-click to finish the spline. This will open the shape up.

You can also right-click a spline and choose: Spline | Open/Close Spline

Name your layers

Naming layers is very important to save yourself time later, especially if you are doing a heavy rotoscoping job. Get into the habit of labeling each layer with specific names.

Turn off the splines and just work with points and the matte

If you are working on a tight roto it can sometimes be easier to turn the spline off and just see the matte with the control points. To do this:

If your other view options are at default settings you should now see the matte in the viewer with only the tangents and control points visible.

The Dope Sheet is used to move, copy and paste keyframes in your layers.

The Curve Editor is used to review how the data in your animation and tracking looks, as well as some value and frame manipulation options.

The Clip module previews your clips in Mocha. It provide basic clip property information.

You cannot manage clips in this version of Mocha. To import additional clips, manage clip streams or handle stereo, you need Mocha Pro.

You can mask down the clip to only allow Mocha to handle parts of the footage.
This is useful when you only need to track some area of the clip, or need to crop out letter boxing.

You can either adjust the Clip mask by moving the yellow dotted line on screen, or manually entering values into the Crop Mask parameters.

Here you can set whether you want the timeline display to be in frames or timecode.

You can now customize keyboard shortcuts for almost every tool, action and menu item in Mocha.

You can create a new profile by duplicating a default profile, then customize the keys. These profiles are then available from the Keyboard menu:

Below are some of the common default shortcuts for Mocha

Preferences are accessed through File | Preferences on Windows or Linux (Mocha Pro only) and Application Menu | Preferences on OS X.

Settings to check for software updates.

If you are working on a number of shots that share the same clip attributes (the same video standard, frame rate and color space), it can be useful to set a default clip setting. Then you will not have to re-enter the same clip information each time you load a clip.

Camera Model

Sets the default distortion mode. In Mocha VR the default is automatically set to 'Equirectangular'. If you are using Mocha VR for non-VR projects often, you may want to set this value to 'No Distortion'.

See the chapter on Keyboard Shortcuts for more information.