Rotoscoping or “Roto” for short has become a generic term for drawing shapes to extract, isolate or affect a portion of an image. It is tedious work, but it’s one of the most important parts of the visual effects process. Within the Roto node, there are all the tools needed to make quick work of any Roto job.

For artists specifically interested in Paint, the Roto node is where you create shapes and trackers which can also be used in the Paint node for match moving brush strokes as well as holdout mattes for painting.

Creating usable shape animations can be a bit tricky with the most common problem being edge chatter. Here’s a few tips to help you on your way.

View your clip to determine the frame that requires the greatest number of points to create the shape. It is easier to draw your shape on the most complex frame as opposed to starting on a simpler frame and adding points later.

In Silhouette, you can create B-Splines (also known as natural splines), X-Splines, Bézier splines, Circles and Squares.

Use as many points as needed to create the shape, but avoid using more than is necessary. The fewer the points, the easier it is to successfully animate the shape. Unnecessary shape complexity inevitably leads to inconsistency when editing points.

Create multiple shapes to Roto complex objects. Drawing separate shapes for the major parts of an object give you finer control over motion especially when separate objects intersect with each other.

Try not to individually move points in a shape unless absolutely necessary. Moving points in groups will maintain consistency and eliminate edge chatter.

Use the tracker to analyze the motion of your clip and then apply that motion to your shapes. This will cut down on the number of keyframes needed.

By editing your shape at various frames in the clip, Silhouette animates the shape in between those keyframes. This saves you work. Make as few keyframes as possible, but as many as needed so the shape properly follows the object that you are rotoing. For instance, on a 80 frame clip, start by adding keyframes at 1, 20 and 40. If more animation is needed, add keyframes at 10 and 30. Get the idea? Creating too many keyframes will cause the shape to jitter or chatter.

For the inpatient among you, here’s a Roto quick start. For all others, Roto features are covered in more detail after this exercise.

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A control point is created.

Use as many points as needed to create the shape, but avoid using more than is necessary. The fewer the points, the easier it is to successfully animate the shape.

Now that you have a shape, you can use either Reshape or Transform to perform editing functions.

Reshape modifies shapes by adjusting their control points and tangents.

Transform affects an entire shape or a group of shapes

The Q, W and E keys allow you to quickly translate, rotate or scale selected shapes while using the Transform tool.

The starting control point is created and sets the direction of the shape’s path.

Although you can use the Reshape tool to later change a shape’s look after drawing it, you can also use the same Reshape keyboard shortcuts to modify a shape while drawing it.

Use as many points as needed to create the shape, but avoid using more than is necessary. The fewer the points, the easier it is to successfully animate the shape.

Control points have two tangents that can extend from it. The path of the curve through the control point is determined by the length and orientation of the tangents. When you drag one tangent’s handle, the adjacent tangent moves as well.

Linear adjusts both tangents one quarter the distance and in the direction of their adjoining control points. Corner collapses both tangents to create a corner point. Cardinal creates a smooth point where the curve passes smoothly through it.

Sometimes a control point’s tangents are so close together that trying to modify the tangent results in movement of the control point. If this is the case, you can force the tangents to move without affecting the control point.

Only the tangent will move, leaving the control point unaffected.

Normally, you move control points to adjust the form of a shape, but you can also move the portion of the curve between control points.

Once you start dragging, the Ctrl/Cmd key can be released.

You may convert your B-Splines or X-Splines to Bézier Splines at any time.

Once you select Convert to Bézier, a couple of things happen. The visibility of the B-Spline or X-Spline is toggled to off. A new Bézier Spline is created and is named the same as the B-Spline or X-Spline but has an * at the end of the name.

A control point is created.

Use as many points as needed to create the shape, but avoid using more than is necessary. The fewer the points, the easier it is to successfully animate the shape.

B-Splines are created by only using control points and are simple to adjust. The position of the points, their weight settings as well as their proximity to each other determine the curvature of the shape. The weight (amount of pull on a point) decides how sharp or smooth it is. Silhouette employs variable weight intensities on a point by point basis.

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A control point is created.

Use as many points as needed to create the shape, but avoid using more than is necessary. The fewer the points, the easier it is to successfully animate the shape.

You can snap the control points of an X-spline to edges of an object by using the Edge Snapping tool.

The points snap to the nearest detectable edge. Alternatively, start dragging the points, hold the Alt-S key down and they will snap to the nearest detectable edge. In some cases, the points may not snap to where you want them to. If this happens, adjust the points manually.

X-Splines are created by using control points and then adjusting their weight to coincide with one of the point types: Cardinal, Polygon or B-Spline. The point type can even be somewhere in between one point type and another.

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Using the Magnetic Freehand tool, you can create a freehand shape with magnetic properties. There are two methods of creating a magnetic shape: Tracing or Strokes.

Trace the cursor along the edge you want to follow and the shape boundary snaps to the nearest edge.

If you want to draw off the edge of the frame, click-hold and drag while tracing to switch to freehand mode.

Draw temporary foreground (inside the shape) and background (outside the shape) strokes for the object you want to create a shape around.

Magnetic and freehand shapes have a fairly high point count to match the subtle changes in the line.The amount of points can be reduced or increased.

Adjusting the Detail reduces points for X-Splines created with the Magnetic Freehand tool, while increasing points for normal X-Splines.

Open shapes are good for rotoscoping strands of hair or thin objects.

A control point is created.

You can also press the Esc key to finish the shape.

Once you draw a shape, there are various ways to modify it. As the object changes over time, you will need to adjust the shape so that it exactly matches the object. The Transform tool affects a shape, a group of shapes or a selection of points.

Point Transform allows you to position, move, scale, rotate, shear or corner-pin a selection of points using the on-screen controls.

A bounding box with on-screen controls appears around the selected points instead of around the entire shape.

Shapes can be moved horizontally or vertically.

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Shapes can be nudged horizontally or vertically using the Arrow keys. One press of the Arrow key moves the shapes 1 pixel. Using the Shift key in conjunction with the Arrow keys moves the shapes 10 pixels.

Scaling changes the size of the shapes.

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To proportionately scale, hold down the Shift key when scaling.

Rotating changes the angle of the shapes.

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The corner points of a shape’s bounding box can be corner-pinned. For instance, you could fit the corners of a shape into the corners of a billboard.

Shapes can be sheared resulting in the shape being skewed horizontally or vertically.

A shape rotates around its center point, but scales from the opposite handle. Moving the anchor point changes the center of rotation and scaling when using the on-screen controls.

Notice how the shape rotates and scales around the Anchor Point.

Shapes can be cut(Ctrl/Cmd-X), copied(Ctrl/Cmd-C) and pasted(Ctrl/Cmd-V).

A shape or selection of shapes can be easily deleted using none other than the Delete key.

The Reshape tool modifies shapes by adjusting their control points and tangents.

Control points can be selected by drawing a rectangular selection. This is the default behavior.

A rectangular selection is created.

Control points can be selected by drawing a freehand polygon.

A freehand selection is created.

Adding control points assists in tracing more detailed objects.

Don’t click on an existing control point because it will move it instead.

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Points can be nudged using the Arrow keys. One press of the Arrow key moves the points 1 pixel. Using the Shift key in conjunction with the Arrow keys moves the points 10 pixels.

While in Magnet mode with multiple selected control points, you can Shift-Alt click/drag in the Viewer, not on any control points or shapes, and that becomes the magnet pull position instead of using a point.

Brush Reshape uses a circular brush to automatically select and then move points when you click and drag them using the Magnetic Reshape behavior.

As with Magnetic Reshape, points near the cursor move more than points farther away.

All points or a selection of points can be numbered.

Numbers are now displayed next to all points.

The points are now tagged for numbering.

Numbers are now only displayed next to tagged points.

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If points are already in a group, a check mark appears next to the number. Also, the group number is underlined if a group already exists.

You can edit point groups within the Normal/Magnetic Reshape modes as well as Point Transform mode.

In the Reshape tool, closed shapes can be opened using the Break option from the control point pop-up menu.

The shape opens at the selected control point.

Shapes can be closed or extended with just a few mouse clicks. It is necessary to use the Reshape tool to perform the following actions.

In the Reshape tool, open shapes can be joined together.

The two shapes are now joined together as one.

Copies the selected control points from a source shape into a target shape, placing them between two adjacent selected points in the target shape.

The selected points from the source shape are copied between the two selected points in the target shape.

Extracts the selected points of a shape into a new closed shape.

The selected controls points are used to create a new closed shape while removing the points from the original shape.

Similar to Split Edit in non-linear editing systems where a clip is split in two, Split Shapes is useful for shapes that transform from simple to complex and vice-versa.

The original shape is duplicated and named Shape-copy. At the current frame, the original shape is set to 0% opacity and the copied shape set to 100%. Both shapes are placed in a layer named Shape-Compound Shape. In editing terms, you are cutting from one shape to another.

Collapses a selection of points into a very small area which can later be distributed between surrounding points. This is useful for shapes whose complexity changes over time.

The points collapse into a very small area.

Evenly distributes selected points.

The points are evenly distributed between surrounding points.

Shape points can be feathered to create variable edged blurs on a point by point basis.

Multiple selected points can be dragged simultaneously and by a proportionate amount. To move the shape and feather points simultaneously, press Shift while moving the shape point.

Multiple selected points can be dragged simultaneously and by a proportionate amount.

In computer graphics, inverse kinematics (IK) is a technique that provides automatic movement of objects. It allows elements of an object to be linked, such as the parts of an arm or leg, and causes them to move in a prescribed, realistic manner. IK simplifies the process of rotoscoping jointed, segmented figures by making the motion of each part related to the motion of the linked parts. That way, you simply have to animate the starting and ending joints, and the ones in between will adjust themselves and create more natural looking movement.

Create shapes for each layer.

Now that the layers and shape have been setup, the joints need to be placed by positioning the Anchor Point of each layer using the Transform tool.

Each layer’s Anchor Point becomes a joint in the IK chain. The “bones” are just the connections between the layer anchors.

When animated, keyframes are automatically set for each layer’s rotation parameter. However, you can explicitly set the layer rotation keyframes by right-clicking on a selected bone and a choosing Add Key.

IK greatly simplifies the rotoscoping of humans, animals and all manner of jointed creatures.

MultiFrame modifies the Transform and Reshape tools to allow you to make adjustments across all previously set keyframes or a selection of keyframes.

The MultiFrame parameters can be set in either the Timebar or Timeline.

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Only keyframes defined in the MultiFrame range are adjusted.

The MultiFrame keyframe adjustment can also be weighted based on a specified Fade In or Fade Out time period. For instance, if an object is slowly drifting, the strength of the adjustment can be faded in or out.

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Note: It can be useful to enable the RotoOverlay > Motion Path to visualize how the weighted MultiFrame is adjusting the shape. Go to the RotoOverlay tutorial to see how it works.

Keyframes within the fade areas are adjusted less than those that are not.

Some nodes like the Point and Flow tracker produce keyframes on every frame in a combination of hard and soft keyframes. Hard keyframes are manually set and help guide the tracker’s generated soft keyframes. To edit and fine tune the tracker keyframes, use Auto mode to smoothly interpolate the soft keyframes located between hard keyframes.

If the track needs to be fine tuned, select the Point tracker or in the case of the Flow tracker, select the shape.

Auto mode smoothly interpolates the soft keyframes located between hard keyframes.

The RotoOverlay tool provides three options to visualize the selected shape’s animation and motion blur: Motion Path, Motion Blur and Onion Skin.

As an alternative to using the pre-defined colors for the Motion Path, Motion Blur and Onion Skin, you can use the default shape colors.

The color of the shape is now used for the selected overlay function.

The Opacity icon indicates the opacity level of a shape. It is white when opacity is 100%, black when 0% and a shade of gray when somewhere in between.

When using the Opacity icon, keyframing is enabled and the animation type is set to Hold. This allows you to conveniently turn the shape on and off with one keyframe.

Shape keyframes can be set automatically using optical flow and the K shortcut key.

The Optical Flow ML node estimates per-pixel motion between frames.

When the K shortcut key is pressed, it uses the optical flow data to calculate the position of the shape’s points.

Cryptomatte creates ID mattes from the Roto node using organizational information available at render time. Cryptomatte generated images are very colorful, assigning each layer or shape a different random color. The Roto layers/shapes in the rendered Cryptomatte EXR file can then be selectively turned on or off in other products that support Cryptomatte like Nuke and After Effects.

Shapes and layers are automatically assigned an ID and rank with layers and shapes being two entirely different sets of Cryptomatic data. Each layer gets its own ID based on its layer name while shapes get their own ID based on their shape name and layer hierarchy.

This determines whether layer, shape or layer+shape Cryptomatte data is written in the EXR file. When you render, the Cryptomatte layer and shape data are written into their own EXR channel.

The Roto layers/shapes in the rendered Cryptomatte EXR file can now be selectively turned on or off. By default, the layers are named CryptoAsset00, CryptoAsset01, CryptoAsset02, etc. while shapes are named CryptoObject00, CryptoObject01, CryptoObject02, etc.

Shapes can be assigned to different channels of an image when rendering.

Now that you have assigned the shapes to different channels, you can visualize the results prior to rendering using View > Channels in conjunction with the Alt-R, G, B and A shortcut keys.

Shapes can be outlined or filled with a color and rendered in the RGB output.

The shape outlines will now render in the RGB output. To change the shape’s outline color, use the Shape > Color parameter.

The shapes are now filled with a color in the RGB output.

Each shape can have its own color.

Silhouette, After Effects, Fusion, gMask (Flint, Flame, Inferno), Nuke and Shake 4.x SSF shapes can all be exported.

If you are exporting using the Silhouette Shapes format, you can also export layers.

To export to After Effects masks, use the Silhouette Shapes option. The Silhouette Shape Import/Export Plug-in is then required to import Silhouette Shapes into After Effects.

A file is saved with the appropriate file extension.

Mocha Pro can export to the Silhouette Shapes format.

A file is saved with the appropriate file extension.

The Silhouette Shape Import/Export Plug-in for After Effects is required to export After Effects masks to Silhouette Shapes. When exporting After Effects masks, the following shape parameters transfer into Silhouette: opacity, blur, shape color, shape name, invert and locked states, transfer mode and per-shape motion blur state.

A file browser opens.

All After Effects masks from the selected layer are exported and a file is saved with a .fxs file extension.

Silhouette, Mocha Pro, After Effects, and Shake 4.x SSF shapes can all be imported into Silhouette.

A file browser opens.

The shapes are added to the current session.

Mocha Pro shapes and layers are imported into Silhouette using the Silhouette Shapes format. If Copy to Clipboard was used in Mocha Pro instead of saving to a file, the shapes and layers are copied to the system clipboard and can then be pasted into a Silhouette Roto node.

Shake 4.x shapes are imported into Silhouette, but attributes such as feathering, color and opacity are ignored.

The Silhouette Shape Import/Export Plug-in for After Effects is required to import Silhouette Shapes and convert them to After Effects masks. When importing Silhouette Shapes, the following shape parameters transfer into After Effects: opacity, blur, shape color, shape name, invert and locked states, transfer mode and per-shape motion blur state.

A file browser opens.

When using the Nuke 9+ Shapes export option, Nuke will import open/closed shapes, the shape feather, opacity, blend mode, invert, motion blur, outline color, fill color, shape blur (inner and outer blur only), and visibility. The layer’s blur, visibility and motion blur are also imported in addition to the node blur. You can optionally fully bake shape and transform data, convert opacity to Nuke Lifetime, and export the Silhouette project name as determined by the Nuke 9+ Shapes preferences.

The Alpha channel in Nuke will now match Silhouette.

Shake will import the shape name, locked/unlocked state, opacity, visibility, motion blur on/off, shutter angle, and shutter phase. In addition, subtractive shapes import into Shake as black in the RGB channels with a white alpha channel.

Motion blur is the directional blurring of rapidly moving shapes. To use Motion Blur, it must be activated for each individual shape as well as in the Roto node.

When working with motion blur, it is best to keep your View set to Foreground. This way editing your shape will be quick and interactive.

When you need to view the motion blurred alpha channel, use Shift-A. Shift-A toggles the View to Output, superimposes the alpha channel over the image and deactivates the Overlay. Pressing Shift-A again returns the Viewer to its previous state.

You can control the motion blur settings simultaneously for multiple Roto nodes using a the Create > Motion Blur Controller action. This action creates a Motion Blur node which controls all other node’s motion blur settings using expressions. The controller includes Enable, Angle, Phase, and Samples parameters, with values defaulting to the first motion blur enabled node settings it finds. It then creates expressions for all nodes in the tree that have motion blur parameters.

You can rename a shape, layer or tracker by:

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The Markup tool creates trackable strokes with associated notes to identify shapes that require revision.

You can type a note for selected objects. Currently, shapes, trackers, depth objects, and layers are supported.

The Notes window comes forward.

Notes can also be displayed with callout lines in the Viewer.

The notes appear in the Viewer with the object name listed along with the note.