Rotoscoping is the process of manually altering film or video footage one frame
at a time. The frames can be painted on arbitrarily to create custom animated
effects like lightning or light-sabres, or traced to create realistic traditional
style animation or to produce hold-out mattes for compositing elements in a
scene.
As a VFX artist, you are primarily creating motion graphics or visual effects.
Without a thorough knowledge of rotoscoping and how it fits into the modern
digital pipeline, you are limiting just how far you can take an effect or design.
The art of rotoscoping changed considerably with the introduction of digital
tools such as Commotion, Digital Fusion (DF), Shake, Combustion (C3) and After
Effects (AE). With a thorough knowledge of rotoscoping, digital artists can
create better live-action or CG composites as well as amazing visual effects.
Various rotoscoping techniques are covered below, including matte creation,
effects painting, paint touchup, digital cloning, and motion tracking as well
as a brief history of the craft.
Historical overview of rotoscoping
Fleischer Studios
A true pioneer of animation, Max Fleischer produced the Popeye and Betty
Boop animated series, as well as the animated features “Gulliver’s
Travels” and "Mr. Bug Goes to Town." With his brother Dave,
he founded the Fleischer Studios in the early 1920’s, which offered a
less sentimental animated vision of the world than the rival Disney studio.
Perhaps most importantly, Fleischer invented the rotoscope, a device that changed
the look of animation forever.
Born
in Vienna Austria in 1883, Max Fleischer immigrated with his family to America
at the age of four. His artistic skills were quickly recognized, and instead
of attending public high school he opted for the Art Students League in New
York. While attending school he landed his first job at the Brooklyn Daily News,
where he worked as an assistant in the cartoon department. Within a few years,
he was a full-time staff artist with his own comic strip. He then moved on to
Popular Science Monthly, which sparked a life-long fascination with machinery
and inventions. While working at this magazine, Fleischer began working on his
plans to create the rotoscope.
Early animated films were crude, jerky and difficult to look at. They were not
very popular and were only tolerated because they were a curiosity. Max Fleischer
aimed to change this by inventing a device that would allow them to project
live action film onto the glass of an animation stand. The animators could then
place paper on the animation stand and trace the live action footage one frame
at a time. This device, named a Rotoscope, was patented by Max Fleischer in
1917.
In a 1920 New York Times interview, Fleischer said, "An artist, for example,
will simply sit down and, with a certain character in mind, draw the figures
that are to make it animated. If he wants an arm to move, he will draw the figure
several times with the arm in the positions necessary to give it motion on the
screen. The probability is that the resulting movement will be mechanical, unnatural,
because the whole position of his figure's body would not correspond to that
which a human body would take in the same motion. With only the aid of his imagination,
an artist cannot, as a rule, get the perspective and related motions of reality."
The rotoscope, though, allowed animators to work from a filmed image, which
gave them the guidance they needed to create more graceful and realistic movement
on screen. "It was beautiful to watch, rather than very annoying to watch,"
Fleischer said.
The
first cartoons created by the Fleischers using the Rotoscope were the Koko the
Clown series, and then went on to utilize it in Betty Boop and Popeye. Though
they used rotoscoping to create the main characters, they continued to rely
on traditional rubber hose style animation in their cartoons. The Fleischers
pioneered other traditional animation priniciples in their studio which changed
the face of modern animation, right up to today. Most animators at the time
would use the technique of “Straight Ahead Action”. Animators would
simply start drawing their sequences at the beginning and straight ahead to
the end. The Fleischers used another technique called “Pose to Pose”
animation, in which the animators would produce main extreme poses, or keyframes,
then fill in the in-betweens. The difference was that the Fleischers would have
assistants draw the in-betweens while the lead animators moved on to create
more keyframes. Though at the time this eventually led to labor problems and
striking workers at Fleischer Studios, the practice is still used today by traditional
cel animation companies, and has been translated into the automatic “tweening”
processes found in computer based animation tools.
During the 1930s, the Fleischers found themselves in an on-going competition
with another animator -- Walt Disney. The Fleischers and Disney constantly raced
one another to each new milestone in animation -- first sound cartoon, first
color cartoon, and first feature. But according to Max Fleischer’s son,
Richard Fleischer, Max and Dave often came in second, largely because the studio
behind them, Paramount, didn't offer the support they needed.
Walt Disney also turned to rotoscoping, for “Snow White”. At the
time, Fleischer considered suing Disney for patent violation, but in doing preliminary
research, his attorneys discovered that before Fleischer's patent, a company
in Wilkes-Barre, Pa., had created a device similar to the rotoscope. The company,
Bosworth, Defresnes and Felton, had never patented it, so Fleischer actually
was entitled to sue, but he evidently lost interest in pursuing the Disney case
after hearing about the earlier machine.
The movements of Snow White herself were acted out by a high school student
named Marjorie Belcher, later known as dancer Marge Champion. Initially, Disney
intended to use Belcher's movements as a guide for the dancing in the cartoon,
but soon he opted to use it more extensively. This was partly because the animators
otherwise used themselves and their own facial expressions as the basis for
their characters' faces, Disney explained. "The artists looking at themselves
in a mirror sometimes were not so successful, because they were bad actors and
would do things in a stiff way," he wrote.
Nevertheless, some of the Disney animators looked down on the idea of rotoscoping.
One of them, Don Graham, derided the technique as a "crutch" for artists
who lacked the skill to do their work on their own. Another, Grim Natwick, said
that even when the artists used the device, they used it only as the basis for
their work, adding heavy elaboration and even changing the proportions of the
original filmed figures. "We went beyond rotoscope," he said.
But rival animator Walter Lantz criticized the look of the rotoscoped work in
"Snow White." In press materials for his own project, "Aladdin
and the Wonderful Lamp," Lantz declared he would use the rotoscope only
for timing because of what he saw as its limitations, especially in Disney's
film. "This literal system resulted in two faults -- a jittering movement
that contrasted with the fluidity of the animals, and the fact that the human
characters were too accurate to be seen beside the caricatures," he said.
Yet rotoscoping did help the artists on "Snow White" maintain a consistency
that might otherwise have been impossible. On earlier animated shorts, each
character was done by a single animator; as a result, the characters had a unity
of style. Because "Snow White" was so extensive, however, more than
one artist had to work on each character. Working from live-action footage offered
them the best way to create a cohesive look.
Analog Rotoscoping for Visual Effects
While
the technique is useful for animation, rotoscoping eventually became an important
tool for visual effects in general. From the 1940s through the 1960s, U.B. Iwerks,
a well-known animator, turned to effects work, where he pioneered the use of
the rotoscope on films such as Alfred Hitchcock's “The Birds” (1963).
Rotoscoping in visual effects was used primarily to make holdout mattes. "You
frequently want to composite different elements into the same shot to create
that shot," explained Tom Bertino, who was head of Industrial Light &
Magic’s rotoscoping department from 1987-93. "By using the tracing
to create black mattes, you can hold out certain elements."
For example, Bertino imagines a scene of an explosion behind two people on-screen,
where the explosion is added after the fact. "You could print the explosion
over the frame. But you'd also cover up the people," he said. "You'd
need to isolate them with the rotoscope." To make a traditional holdout
matte, a rotoscope artist would trace the figures that had to be isolated onto
an animation cel. The outline traced onto the cel then would be filled in with
black paint, so that it would block the appropriate section of the frame. "You
create a solid black matte," Bertino said. This black matte then could
"hold out" the part of the explosion image where the two people would
appear, so that when the two images were printed together, the people would
appear to be in front of the explosion.
Rotoscoping
also could be used to stabilize a shaky film image. To do stabilization, each
film frame was rotoscoped onto an alignment chart. A comparison of the charts
allowed changes in position to be tracked from frame to frame. Using this information,
an optical copy of the film could be made, with the printer offsetting the shifts
in each frame's movement.
Bertino said people underestimate the difficulty of rotoscoping during the photochemical
era: "It was a painstaking process. There were so many moving parts to
the rotoscope camera, and so many places for things to get out of hand."
Rather than being a refuge for the unskilled artist, he added, rotoscoping was
a demanding craft. "The rotoscoper had to be a skilled animator to make
the line follow through. That's actually something that plagued some early uses
of the rotoscope as a special effects tool -- without actual animators to handle
it, it could get jittery."
Good rotoscope artists were very precise about their work. "It was so exacting,"
Bertino said. "It's almost like -- I don't know if you’ve ever seen
those incredibly detailed Chinese tapestries that they made in the monasteries
generations ago. They finally stopped making them because the artisans would
go blind. I'm surprised that more rotoscopers didn't go that route."
Jack Mongovan, a paint and rotoscope supervisor at ILM, began his career in
traditional rotoscoping and has been working in the field for 19 years. He remembers
working in rooms that were completely dark except for the light coming out of
the projector. The rotoscope artists were at the mercy of the painters who would
later fill in their outlines, and who could with a few stray brushstrokes outside
the outline make the image suddenly jittery. "I would never go back to
traditional for anything," Mongovan said.
Digital rotoscoping for Visual Effects
Today, rotoscoping is done in the computer, using programs such as Shake,
FFI and Pinnacle Commotion. The shift to computer-based rotoscoping began in
the early 1990s with a software called Colorburst, an image editing tool like
Photoshop, that later evolved into Matador. "When computers became prodigiously
viable around here, right after the 'Terminator 2'/'Jurassic Park' era, we realized
that the computer had great capabilities for this," Bertino said. "It
obviously became much simpler."
Mongovan said that today, one rotoscope artist can do the same amount of work
that eight used to do, and in one quarter of the time. This is often because
in traditional rotoscoping, each frame had to be drawn individually. The computer,
on the other hand, can use the previous frame as a basis, which means most of
the drawing may already be done.
Rotoscoping software works using splines, which are a series of points connected
by a line or curve. These splines are adjusted from frame to frame, so that
they continue to conform to whatever shape the artist is tracing. Because rotoscoping
software includes the tools to paint an image, rotoscope artists now find themselves
doing a lot of paint work as well. "Rotoscoping is becoming the lesser
part of what we do," Mongovan said. "We do so much more painting."
Painting might mean taking someone out of a shot, or replacing a sky, or painting
out the tennis balls used as visual effects tracking markers.
Some skills remain necessary, including a sense of what is important. "One
of the hardest things for people to do in our department is to realize that
they're looking at a very zoomed-up plate," Mongovan said. Also, he pointed
out, a movie audience will see an image for only 1/24th of a second, too short
a time to register flaws that may torture the artists. More important is consistency.
"I tell people, 'You can paint that first frame wrong, just keep it wrong
it all the way through.'"
That kind of understanding is key, Bertino agreed. "The secret to good
rotoscoping has always been -- regardless of what it's used for -- an educated
eye and good judgment as to what to include and what to leave out," he
said. "Most people think the rotoscope is very literal -- you trace what's
there, and that's it. It's possible to put too much detail and confuse matters.
You need to have that sense for judicious editing. That hasn't changed at all.
And not everybody's got that."
After Effects was the first tool to bring professional compositing motion graphics
and effects functionality to the desktop. After Effects was originally developed
by CoSA, then aquired by Aldus, which in turn was aquired by Adobe. After Effects
had very limited rotoscoping tools in earlier versions, with only one rotospline
and no paint tools, but this is slowly changing. Version 4 added multiple rotosplines
for cutting mattes, version 5 added vector paint, and version 6.5 has added
cloning tools and tracker advancements (we still haven't tested these improvements).
It is still lacking b-splines as well as the realtime roto performance found
in more advanced roto tools like Commotion. Tip: Red Giant software offers a
Commotion to AE roto import plugin
Discreet’s
Advanced System, which include Flint, Flame, Inferno, Fire, and Smoke, run on
SGI workstations and range in price from $60,000 to over $500,000. These products
offer a complete post-production solution, including very powerful and fast
rotoscoping tools. The painting and cloning tools are top notch, with excellent
brushes and advanced features including brushed based warping. The rotosplining
functionality is excellent, though not quite up to par with Commotion due to
a lack of b-splines and the inability to play spline over a moving image in
realtime. Tracking is very fast and very accurate. Many facilities using Discreet’s
advanced systems offset roto work to Macs and PCs running Commotion, Shake or
Combustion.
In
1997, Discreet aquired Paint and Effect from Denim Software. Paint offered a
vector based painting and cloning system for Mac and PC, while Effect offered
compositing capabilities. Discreet re-designed the interfaces to make the applications
more Discreet like, and merged the two applications into Combustion. Along the
way, they also replaced some of the core functionality like Keying, Color Correction,
and Tracking with the same tool set found in Discreet’s Advanced Systems.
Combustion 2.0 added additional Advanced Systems features, including the same
rotosplines found in Flame. Combustion 3.0 took the product even further with
an edit operator, flash output and much more, most significantly a flow diagram
UI feature that many users feel more comfortable working with. Combustion roto
spline files can be opened directly in the larger Inferno/flame/flint products.
Curious gFx Pro
gFx
is a relatively new product for the Mac OSX. Unlike other paint programs it
is designed around a stong user interface that fully embraces moving footage,
as such it can import, composite, track, or stablise footage easily. The spline
shapes can not yet be exported and the product does not fully import Photoshop
files and maintain their structure, but this is planned for an upcoming release.
the product does have specialist wire removal tools and a very friendly and
interactive user interface. One of Curious's founders is the man behind Parrallax,
and it shows in some of the depth of tools already available, 16bit raster paint
with an excellent brush engine, and b-spline rotosplines with an excellent transform
points UI, motion blur on splines, grouping splines, selective edge feathering
(ie. advanced gradient), and more.
Digital
Fusion started in Sydney and moved to Toronto, Canada. At one stage a version
of Fusion was provided with Alias 3D - but today Eyeone has gained one of the
strongest postions in NT/Windows desktop compositing solutions. Eyeon has two
main products Digital Fusion and DFX +.
Digital Fusion 4 is eyeon’s flagship product and marks the ninth major
release of this powerful compositor. DFX+ 4 is the 8-bit expandable version
of eyeon’s image processing software, Digital Fusion. DFX+ is based on
the architecture of DF4 and offers a number of significant enhancements to its
predecessor, DFX, including the flexible flow, superior character generation,
PSD import into separate layers for animation, and more.
Since Shake's move away from NT/Windows DF has provided a powerful cost effective
solution.
Shake Shake
has 3 options for Roto, Quickpaint, Quickshape, and Rotoshape. Quickpaint is
a procedural paint package inside Shake. You can paint frame by frame and then
view in realtime or paint with interpolation. As all the paint elements can
be animated over time it is a reasonable roto tool. Quickshape is a basic roto
tool, somewhat now completely over shadowed by Rotoshape. Rotoshape allows variable
edge softness and logical operations between roto shapes. The rotos in Rotoshapes
are classic spline shapes with complex parent child relationships - and velocity
based motion blur. For complex rotoscoping this gives very accurate results.
Both Rotoshape and quickpaint can use shakes 2D trackers. It is worth noting
that given Shake is a node workflow model it is possible to paint or roto through
a track or image transform.
The
most ubiquitous graphics application in the world was probably the first digital
rotoscoping tool to be used in film and video post production. Though Photoshop
was initially intended for still images, it can work with motion by importing
frames one at a time or importing filmstrip files from video applications. Photoshop’s
brush engine is the benchmark everyone else strives for, and gives excellent
control when using pressure sensitive Wacom tablets. The biggest drawback is
a lack of a realtime preview of sequential frames. You will not know how well
your cloning is working out until you play back your clip in realtime at full
resolution. After painting numerous frames in Photoshop, the sequence must be
brought back into an editing or compositing application such as Final Cut Pro
to see realtime playback. This is a painfully slow way of working. And since
it isn’t intended for video, it lacks travelling matte capabilities and
motion tracking.
Developed by Industrial Light and Magic Visual Effects Superviser Scott Squires,
Commotion was used for years at ILM before Scott formed Puffin Designs and released
it to the public. Commotion, then called Flipbook, was often sighted at ILM
and mistakenly referred to as the “secret ILM motion version of Photoshop”.
Though Commotion looked very similar to Photoshop in some respects, Commotion’s
interface and tools were designed for moving images, and was the first tool
on the desktop to offer realtime ram based playback. This realtime core functionality
was the foundation for all of the roto tools added as the product developed.
Advanced roto tools include raster based paint, spatial and temporal cloning,
wire removal tools, auto-paint, unlimited bezier and natural cubic b-splines,
motion blur on rotosplines, and a very fast and accurate motion tracker. Commotion
quickly became the de-facto roto tool in the industry, replacing Matador in
most post facilities. Puffin Designs was aquired by Pinnacle Systems in 2000,
but sadly development has stopped on the product, most if not all the original
developers has long since left and no new work has really been done on the product
in the last 3 years. Importantly Commotion curves can be exported and imported
into AfterEffects, see AE above.
Matador was originally developed by Brittish developer Parralax, and acquired
by Avid along with Parralax’ compositing application Illusion. Available
only on the SGI platform and priced around $15,000, Matador was one of the first
digital rotoscoping tools which gained a wide acceptance in the film post production
pipeline. Matador started as a tool made for editing still images, so many of
the tools used for motion work were not well thought out. Matador provides excellent
matte creation tools including b-splines, motion tracking, and a full set of
painting and cloning tools, with full 16bit/channel support. Avid stopped development
of Matador in the late 90’s. The original developers tried to spin it
off into a new company called “Blue”, but that never took off.
There are new Roto tools that have now been incorporated into Softimage XSI
compositor in V.4, but these are not Matador - as many people believe.
Newtek is mostly known for their 3D application Lightwave. Aura was a stand-alone
paint application designed for film and video. It hasn’t become widely
accepted in the industry, and mostly used by Lightwave users to finesse 3D renders.
Some advanced features include a 16bit/channel paint engine, and auto-paint.
Newtek has now stopped supporting the program and as of June 2003 with Lightwave
3D 7.5 - Newtek offers DFX+ at no additional cost.
Originally developed as a product named “Roto” by a failed start-up
company called Post Digital, Roto DV was aquired by Radius, which later turned
it’s name into Digital Origin, and then was aquired by Media100. Though
it was called Roto, it actually didn’t have very sophisticated roto tools,
and the ones that were actually pretty cool never made it into the shipping
product. Media100 has no information on their website about this product, so
we assume it is no longer developed or supported.
Rotoscoping in the modern post-production pipeline.
Effects Painting
Effects Painting is generally used to quickly add new elements to
a scene. Instead of creating elaborate particle effects in 3D simulation software
like Maya, many effects can be done faster by a skilled artist using a paintbrush
or airbrush in a paint application. Effects like lightning or light-sabres can
be painted one frame at a time. More advanced roto tools offer auto-paint capabilities
which allow you to record brush strokes and then play them back over a selected
range of frames. Some roto applications also allow you to add jitter to the
brushes, as well as add the ability to paint the stroke out over time.
There are two types of paint engines used in modern graphics applications; Bitmap
(also known as raster) and Vector. Raster paint engines are destructive in the
sense that they replace the pixels being painted onto with the color from the
paint stroke. Photoshop, Commotion, and Flame are raster based applications.
This is a very fast way of working since the frame is immediately updated and
the results can be played back in real time without rendering. Vector based
paint engines, like Illustrator, Shake, After Effects Vector Paint, or Combustion,
use points and splines to define a brush stroke, and do not destroy the underlying
pixels. This non-destructive process allows you to edit paint strokes at any
time, though you pay the price in speed since the strokes need to be rendered
before they can be previewed in realtime. The other disadvantage is that hundreds
of channels will be created with the spline information even if you do not plan
on using them.
Cloning/Paint Touch-Up
Most paint work done in the rotoscoping process is used for touching
up film or video footage. This includes removing wires and rigs, removing logos,
dust busting, scratch removal, etc. In these circumstances, the roto tool must
be able to provide temporal and spatial cloning. Spatial cloning is a type of
cloning which takes pixels from one position of the frame, and paints the source
onto another position on the frame. Photoshop’s rubber stamp tool is an
example of spatial cloning. Temporal cloning allows you to paint pixels from
one frame in a sequence to another frame. Commotion’s Super Clone tool
is an example of temporal cloning. A good roto tool should provide both of these
options together so users can offset position and frame number together. Other
cloning tools include wire removal tools which allow you to draw a line to zip
out a wire. Typically, wire removal tools clone pixels from a specified value
on either side of the line, then smear the outside pixels together to cover
up the wire or scratch. More advance wire removal tools will add advanced cloning
techniques to the wire removal process. For example, Commotion looks at a specified
number of pixels on either side of the line, flips those pixel values then cross
dissolves to cover up the wire.
There are excellent specialist plugin tools for wire removal such as Tinder's
Furnace plugins for Shake and discreet's inferno or flame
Matte creation (Keying, Rotosplining, Painting)
Creating hold-out mattes, sometimes referred to as masks or alpha
channels, is a major piece of the compositing process. A matte is a grayscale
clip which is used to stencil portions of the background footage. Anything in
the black area will be obscured, and anything in the white area will show through
(in some systems like Avid this is backwards). Any gray area in the matte will
be semi-transparent. Roto artists are expected to cut precise mattes with consistent
edges which will not chatter. If the matte is sloppy, the shot will look fake.
The best compositor will produce unacceptable work if provided with poor mattes.
Mattes can be created with three different techniques; Extraction, Rotosplining,
and Painting. For most situations a combination of these three techniques will
have to be used.
Extraction is the process of procedurally generating a black and white matte.
This can be done by shooting an element against a blue or green screen, then
using a color keyer to knock out the specified color. Sometimes bluescreens
are not practical, and in these cases other types of extractions need to be
performed. Luminance keying can extract a matte based on the luminance values
of the source. Either dark or light areas can be extracted into a matte. An
image can be de-saturated then leveled to create a high contrast matte. Sometimes
it is better to start with one of the color channels to create an extraction.
It is always a good idea to check out each color channel to see how the contrast
looks, then pick the best one to start leveling into a high contrast matte.
The Shift Channels filter in AE or Commotion can shift one of these color channels
into the Alpha Channel, which can then be leveled into the final matte. Another
type of extraction is Difference Keying, which generates a matte based on differences
between two clips.
Rotosplining is the process of creating vector shapes to manually cut an element
out of it’s background. These shapes can be re-positioned on various keyframes,
and the software will interpolate the in-betweens. The process isn’t as
automatic as an Extraction, but at least the computer can interpolate some of
the frames for you. Good roto tools will offer multiple rotosplines with the
ability to keyframe each shape separately. By using multiple splines, complex
elements can be cut out from their background. For example, an actor running
would have separate shapes for the hand, forearm, upper arm, chest, torso, thigh,
shin, etc. By breaking the shapes down into smaller elements, it is much faster
to set the keyframes by moving the shape and not individual points, and the
software will interpolate much more accurately. Commotion has the most advanced
rotosplining tools on the market. Most applications use bezier splines for their
rotosplines, which require tweaking both the points and the handles. Commotion
has bezier splines, but the real power is in the B-Splines, which are much easier
to control. B-Spline, also called Natural Splines, do not have the handles found
on Beziers. Instead they always create a curved surface depending on how far
apart the points are. The points default to an average tolerance, and can be
interactively changed to loosen or tighten the curve. B-Splines are consistently
faster and easier to work with than beziers. Commotion also has the ability
to play multiple shapes in realtime over the background footage. This allows
you to quickly preview how your shapes are animating compared to the source
footage. Other important functions found in Commotion’s rotosplining tools
include directional feathering, unlimited splines, color coding and naming splines,
motion blurred mattes based on direction and velocity of the splines, a curve
editor for fine tuning the motion between keyframes, rotating and scaling splines
and selected points, global position offsets, and composite previews.
Mattes can also be generated with paint tools. This is generally the last resort,
as painting mattes generally will produce inconsistent results due to the fact
that every frame needs to be painted on. Auto-paint functionality can help with
this consistency problem, but for the most part painting mattes should be left
for final tweaking of an extracted or rotosplined matte. Advanced rotoscoping
tools offer the ability to paint mattes directly into the Alpha Channel while
continuing to see an overlay of your RGB channel. This is sometimes referred
to as a Mask Overlay, or QuickMask, and is crucial for painting complex mattes.
Motion Tracking Motion Tracking is a computer based process which analyzes a pixel
or sub-pixel in a clip, and follows that pixel or sub-pixel to find the exact
coordinates on each frame. There are two primary uses for motion tracking. The
first is for stabilization, and the second is for match moving.
Once a motion tracker knows where a sub-pixel is on every frame, it can re-position
the image on every frame in the opposite direction to counteract a camera shake.
This stabilization process works fantastic in most cases. Tracking one point
allows you to stabilize position. Adding a second tracker will allow the software
to compare the relative positions of the two trackers, which can also stabilize
rotation and/or scale.
The second use for motion tracking is match moving. If you needed to add a logo
to a car door, you can track the handle on the door, then apply that data to
a logo on another layer. As mentioned above, a second tracker can be added to
match move a logo which needs to rotate and/or scale. If perspective changes,
four point tracking can be used to track four points. Each tracker can then
be assigned to a corner of a CornerPin filter applied to the image.
Serious roto tools need motion tracking to help automate tedious processes,
as well as to produce convincing results. Motion trackers should allow you to
track 1, 2, and 4 points simultaneously. Advanced trackers, like the one found
in Commotion, allow for unlimited point tracking, and access to the tracked
data in text format so it can easily be used in other applications (Commotion
can export text, as well as data formatted for AE, Flame, Digital Fusion, Electric
Image, and other apps). Motion trackers should also allow you to apply the tracking
data to rotosplines and individual points on a rotospline for automated matte
creation, as well as attaching tracker data to paint and cloning tools. And
most importantly, the motion tracker has to be accurate. Flame, Shake, Digital
Fusion and Commotion have the fastest, most accurate trackers.
There are excellent program for 3 dimensional camera tracking but these are
rarely used for roto, however programs such as boujou and boujou bullet will
import b/w rotos to aid in tracking
Born
in Vienna Austria in 1883, Max Fleischer immigrated with his family to America
at the age of four. His artistic skills were quickly recognized, and instead
of attending public high school he opted for the Art Students League in New
York. While attending school he landed his first job at the Brooklyn Daily News,
where he worked as an assistant in the cartoon department. Within a few years,
he was a full-time staff artist with his own comic strip. He then moved on to
Popular Science Monthly, which sparked a life-long fascination with machinery
and inventions. While working at this magazine, Fleischer began working on his
plans to create the rotoscope.
The
first cartoons created by the Fleischers using the Rotoscope were the Koko the
Clown series, and then went on to utilize it in Betty Boop and Popeye. Though
they used rotoscoping to create the main characters, they continued to rely
on traditional rubber hose style animation in their cartoons. The Fleischers
pioneered other traditional animation priniciples in their studio which changed
the face of modern animation, right up to today. Most animators at the time
would use the technique of “Straight Ahead Action”. Animators would
simply start drawing their sequences at the beginning and straight ahead to
the end. The Fleischers used another technique called “Pose to Pose”
animation, in which the animators would produce main extreme poses, or keyframes,
then fill in the in-betweens. The difference was that the Fleischers would have
assistants draw the in-betweens while the lead animators moved on to create
more keyframes. Though at the time this eventually led to labor problems and
striking workers at Fleischer Studios, the practice is still used today by traditional
cel animation companies, and has been translated into the automatic “tweening”
processes found in computer based animation tools.
While
the technique is useful for animation, rotoscoping eventually became an important
tool for visual effects in general. From the 1940s through the 1960s, U.B. Iwerks,
a well-known animator, turned to effects work, where he pioneered the use of
the rotoscope on films such as Alfred Hitchcock's “The Birds” (1963).
Rotoscoping
also could be used to stabilize a shaky film image. To do stabilization, each
film frame was rotoscoped onto an alignment chart. A comparison of the charts
allowed changes in position to be tracked from frame to frame. Using this information,
an optical copy of the film could be made, with the printer offsetting the shifts
in each frame's movement.
Discreet’s
Advanced System, which include Flint, Flame, Inferno, Fire, and Smoke, run on
SGI workstations and range in price from $60,000 to over $500,000. These products
offer a complete post-production solution, including very powerful and fast
rotoscoping tools. The painting and cloning tools are top notch, with excellent
brushes and advanced features including brushed based warping. The rotosplining
functionality is excellent, though not quite up to par with Commotion due to
a lack of b-splines and the inability to play spline over a moving image in
realtime. Tracking is very fast and very accurate. Many facilities using Discreet’s
advanced systems offset roto work to Macs and PCs running Commotion, Shake or
Combustion.
In
1997, Discreet aquired Paint and Effect from Denim Software. Paint offered a
vector based painting and cloning system for Mac and PC, while Effect offered
compositing capabilities. Discreet re-designed the interfaces to make the applications
more Discreet like, and merged the two applications into Combustion. Along the
way, they also replaced some of the core functionality like Keying, Color Correction,
and Tracking with the same tool set found in Discreet’s Advanced Systems.
Combustion 2.0 added additional Advanced Systems features, including the same
rotosplines found in Flame. Combustion 3.0 took the product even further with
an edit operator, flash output and much more, most significantly a flow diagram
UI feature that many users feel more comfortable working with. Combustion roto
spline files can be opened directly in the larger Inferno/flame/flint products.
gFx
is a relatively new product for the Mac OSX. Unlike other paint programs it
is designed around a stong user interface that fully embraces moving footage,
as such it can import, composite, track, or stablise footage easily. The spline
shapes can not yet be exported and the product does not fully import Photoshop
files and maintain their structure, but this is planned for an upcoming release.
the product does have specialist wire removal tools and a very friendly and
interactive user interface. One of Curious's founders is the man behind Parrallax,
and it shows in some of the depth of tools already available, 16bit raster paint
with an excellent brush engine, and b-spline rotosplines with an excellent transform
points UI, motion blur on splines, grouping splines, selective edge feathering
(ie. advanced gradient), and more.
Digital
Fusion started in Sydney and moved to Toronto, Canada. At one stage a version
of Fusion was provided with Alias 3D - but today Eyeone has gained one of the
strongest postions in NT/Windows desktop compositing solutions. Eyeon has two
main products Digital Fusion and DFX +.
Shake
has 3 options for Roto, Quickpaint, Quickshape, and Rotoshape. Quickpaint is
a procedural paint package inside Shake. You can paint frame by frame and then
view in realtime or paint with interpolation. As all the paint elements can
be animated over time it is a reasonable roto tool. Quickshape is a basic roto
tool, somewhat now completely over shadowed by Rotoshape. Rotoshape allows variable
edge softness and logical operations between roto shapes. The rotos in Rotoshapes
are classic spline shapes with complex parent child relationships - and velocity
based motion blur. For complex rotoscoping this gives very accurate results.
Both Rotoshape and quickpaint can use shakes 2D trackers. It is worth noting
that given Shake is a node workflow model it is possible to paint or roto through
a track or image transform.
The
most ubiquitous graphics application in the world was probably the first digital
rotoscoping tool to be used in film and video post production. Though Photoshop
was initially intended for still images, it can work with motion by importing
frames one at a time or importing filmstrip files from video applications. Photoshop’s
brush engine is the benchmark everyone else strives for, and gives excellent
control when using pressure sensitive Wacom tablets. The biggest drawback is
a lack of a realtime preview of sequential frames. You will not know how well
your cloning is working out until you play back your clip in realtime at full
resolution. After painting numerous frames in Photoshop, the sequence must be
brought back into an editing or compositing application such as Final Cut Pro
to see realtime playback. This is a painfully slow way of working. And since
it isn’t intended for video, it lacks travelling matte capabilities and
motion tracking.
