what is Rotoscoping...?
Rotoscoping is an animation technique in which animators trace over live-action film movement, frame by frame, for use in animated films[1]. Originally, pre-recorded live-action film images were projected onto a frosted glass panel and re-drawn by an animator. This projection equipment is called a rotoscope, although this device has been replaced by computers in recent years. In the visual effects industry, the term rotoscoping refers to the technique of manually creating a matte for an element on a live-action plate so it may be composited over another background.
Tools for Rotoscoping
After Effects
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
Flint/Flame/Inferno/Fire/Smoke
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.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
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.PhotoshopThe 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.Other older products:
Commotion
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
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.
Aura
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.
Roto DV
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.
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Techniques of rotoscoping
Analog Rotoscoping for Visual Effects
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."
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History of rotoscoping
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.
Disney
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.
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