Vfx
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VFX - Digital Visual Effects Movie Magic...
Almost any Hollywood movie that you see today uses visual effects -- from the ships in "Star Wars" to the monsters in "Godzilla," visual effects make the imaginary look completely real! Visual effects help enhance the look of a movie or create scenery and situations that cannot (or do not) exist in real life.
The visual effects are obvious in any science fiction film -- of course the scenes of spaceships battling one another in far-off galaxies are not real. The only way to create these scenes is through an amazing set of tools and technologies that let imaginary places look totally real.
What you may find surprising is that almost every Hollywood movie produced today contains visual effects of some sort. VFX is also known as Digital Visual Effects or DFX - the word digital in the phrase digital visual effects means that VFX houses primarily uses computer hardware and software to create their effects.
The general term used in the industry for what VFX houses do is CG, short for computer-generated. For example, when talking to the artists you will hear them say things like, "That entire scene is CG," or "Those are all CG soldiers," or "The actors are real, but everything else is CG."
Computer-generated effects make imaginary characters like Godzilla possible, and they also create almost every effect that used to be done using models. The advantages of CG effects are their realism, flexibility and relatively low cost (compared to the alternatives).
A VFX team works with the movie's director both during filming (production) and then extensively after filming (post-production) to create the effects. Involvement during production helps the director make creative decisions so that the effects can be integrated into the film more easily, and also allows a VFX team to add different markers and other features to each scene to make post-production work easier.
VFX Markers on a greenscreen
For example, in certain scenes the camera might be fitted with encoders that will allow for easier integration of the effects that the VFX team creates. During post-production, the director works extensively with the VFX team to make sure that the effects in each shot have exactly the right look for the film.
A typical movie might have 1,000 to 1,500 shots. A shot might be one or two seconds long, or 30 to 60 seconds long. A given scene in a movie might be filmed with a number of different cameras so that there are wide vistas, close-ups, changes of perspective and so on. In the final movie, these different viewpoints are mixed together to create the scene.
Therefore a single scene might contain dozens of individual shots. By splicing all of the shots together in the correct order you create the complete movie.
The VFX Process
Step 1: Scanning
Hollywood movies are typically shot on 35mm film at 24 frames per second. The first step of the visual effects process is deciding which of the shots need to have visual effects applied to them.
The rolls of film for these shots are then scanned, or digitised, in a hermetically sealed scanner room. Most reels are scanned at ‘2K’ resolution (2,048 x 1,556 dots per frame), an average VFX film may have around 150 shots, the ‘intermediate files’ for these 150 shots would consume about 1.5 terabytes of disk space.
Once it is digitised, a shot may go through a number of 3D & 2D artists. A big part of realistic computer generated effects is the creation of 3D models and characters and their integration into final composites by 2D artists.
3D Processes
3D Tracking The tracking department uses markers added to the scene to create a 3-D model of the scene and then a 3-D camera. The goal is for the 3-D camera to exactly mimic the motion of the real camera so that the 3-D elements added to the scene look right and move correctly as the camera moves in the actual scene.
3D Modelling A 3-D model is a collection of shapes that form the outside of the object being modeled. Most 3-D or CG creatures are formed from a combination of spheres, cylinders and other shapes that are molded on the computer screen into exactly the right configuration to look like the creature they are representing.
3D Setup Setup is the process of adding a "skeleton" of bones and joints to a 3-D model so that the different shapes in the model move correctly with respect to one another. In some cases the bones and joints are created by hand. In other cases they come from motion capture data.
Motion Capture To gather motion capture data, an actor is fitted with a suit that has reflective markers or lights at every joint. The actor moves on a special stage and 3-D cameras watch the actor from a number of different angles.
Computer software is then able to track all of the markers and, with the help of a technician, bind them together into a stick figure that accurately duplicates the motion of the actor. The stick figure is the bones and joints that then control and animate a 3-D model.
Mo-Cap Transformation
3D Animation In the animation process, an artist choreographs the movement of a 3-D character. Objects (models) are built on a computer (modeled) and 3D figures are rigged with a virtual skeleton. Then the limbs, eyes, mouth, clothes, etc. of the figure are moved by the animator on key frames.
2D Processes
2D Painting Painting is used extensively by any visual effects team. e.g. Create matte paintings for backdrops
Paint out wires, harnesses, brackets and other safety equipment Paint over the "holes" sometimes created by rotoscoping Touch up things like grass that has lawn mower tracks in it
2D Compositing Compositing is the process of adding all of the different layers (these layers are known as elements, or plates) of a shot together to create the final shot. The compositing artist incorporates all of the elements in the right order so they overlay each other properly to create the final shot. This is one of the most difficult aspects of the VFX process, as artistic training, technological proficiency, an understanding of cinematic conventions and an eye for detail are all required.
A visual effects team is responsible for all of the effects shots in a single film. At PHOTON, a team consists of a producer, several supervisors (for example a 3-D supervisor, a 2-D supervisor, etc.) and a number of artists. One of the first tasks for the team is the research and development process.
The team then uses what it creates during the R&D process to manipulate the shots it is responsible for. With the help of the supervisors and artists on the team as well as the film's director, the producer's job is to look at all of the shots, understand what the director wants to change in each one and then estimate the amount of time that all of the tasks will take.
A bubble plate from Ghosthip
The Technology
Digital visual effects at the Hollywood level require an incredible technology infrastructure that includes both hardware and software. The machine room pictures that follow shows just how extensive the hardware investment is. The team needs massive amounts of hardware for four reasons:
The scanned film and the different layers that the team creates require gigantic amounts of disk space. A single frame of a film, once scanned and stored on a disk, consumes on the order of 10 megabytes of disk space. All of the shots of "Ghostship" together consumed 1.6 terabytes of disk space.
Individual artists need high-end desktop machines to work on and render their individual models and layers. Pictured at right are the Silicon Graphics workstations used to power Flint, Flame & Inferno.
Rendering requires massive CPU resources. To render any animated 3-D figure or any effect like water or smoke, the CPU must generate millions of polygons, lines, points, etc and then light them correctly. And it must do this over and over again for each frame of the shot!
Compositing Compositing combines dozens of layers into a single shot. Because of the resolution involved -- millions of pixels and tens of millions of bytes per frame -- and the layering, both the CPU workload and the storage requirements are immense.
A thousand words...
The easiest way to understand what a visual effects team can do is to look at an example. The first example that we will use involves a surprising number of techniques to completely change the landscape from a wooded field to a seaside town! This is a shot from the movie "The Patriot." To get a feeling for the total transformation, take a look at these two short videos. The first shows the original shot as filmed. The second shows the scene as it appears in the movie:
Before & After This section of video is 20 seconds long, or about 480 frames.
Step by Step
First, a variety of things might be done to the original shot to clean it up, correct the color and so on. Since the camera pans across the scene in this shot, the next step is to build a 3-D model of the camera so that all of the visual effects the team will create will mesh with the original scene exactly
One of the first steps taken to add visual effects to the scene is the rotoscoping. An artist sits at a computer and, frame by frame, outlines the portion of the original shot that will be used in the final version. Rotoscopers are known within the industry as ‘Roto Dogs’, due to their relatively low place in the VFX food chain!
The breastworks, a portion of the field and several of the running soldiers will all be used, but the explosion seen on the left and everything else will be removed. The artist will outline these elements and create a ‘matte’ that can be used to create an empty space in a background scene. This allows a new object to be placed in the scene. Another camera crew has created an ocean shot. Once the ocean shot is cleaned up and color-corrected, it and the rotoscoped scene can be integrated:
Rotoscope Integration
Another artist in the paint department has been working on a matte painting of the town. This is a highresolution digital image created using a painting/ illustration package. Once the town is added in, the scene looks like this:
Town Integration
In this shot there are a number of boats encircling the town and firing on it. The boats are all computer generated. Each one is modeled and then added to the shot:
Boat Integration
The cannon fire for the boats is its own stand-alone effect that is created separately and then added to the shot. A variety of other effects are added to the shot, including things like smoke over the town, people in the town, a large explosion on the right, etc.
Cannon Fire
The final step in the process is compositing all of the different components of the shot (the rotoscoped foreground, the water, the town, people in the town, the boats, the cannon fire, the smoke, the explosion, birds flying overhead and so on) layer by layer to create the final shot as it will appear in the movie. Once digitally composited, the shot is written back to film so that it can be spliced into the movie.
Final Composited Scene
This brings us to the end of our topics for this semester. Next week we will be doing a lightning fast revision of the topics covered over the last 12 weeks. Make sure you make it next week as we will also have a general question time where you can clear up anything you are not quite sure about.
Almost any Hollywood movie that you see today uses visual effects -- from the ships in "Star Wars" to the monsters in "Godzilla," visual effects make the imaginary look completely real! Visual effects help enhance the look of a movie or create scenery and situations that cannot (or do not) exist in real life.
The visual effects are obvious in any science fiction film -- of course the scenes of spaceships battling one another in far-off galaxies are not real. The only way to create these scenes is through an amazing set of tools and technologies that let imaginary places look totally real.
What you may find surprising is that almost every Hollywood movie produced today contains visual effects of some sort. VFX is also known as Digital Visual Effects or DFX - the word digital in the phrase digital visual effects means that VFX houses primarily uses computer hardware and software to create their effects.
The general term used in the industry for what VFX houses do is CG, short for computer-generated. For example, when talking to the artists you will hear them say things like, "That entire scene is CG," or "Those are all CG soldiers," or "The actors are real, but everything else is CG."
Computer-generated effects make imaginary characters like Godzilla possible, and they also create almost every effect that used to be done using models. The advantages of CG effects are their realism, flexibility and relatively low cost (compared to the alternatives).
A VFX team works with the movie's director both during filming (production) and then extensively after filming (post-production) to create the effects. Involvement during production helps the director make creative decisions so that the effects can be integrated into the film more easily, and also allows a VFX team to add different markers and other features to each scene to make post-production work easier.
VFX Markers on a greenscreen
For example, in certain scenes the camera might be fitted with encoders that will allow for easier integration of the effects that the VFX team creates. During post-production, the director works extensively with the VFX team to make sure that the effects in each shot have exactly the right look for the film.
A typical movie might have 1,000 to 1,500 shots. A shot might be one or two seconds long, or 30 to 60 seconds long. A given scene in a movie might be filmed with a number of different cameras so that there are wide vistas, close-ups, changes of perspective and so on. In the final movie, these different viewpoints are mixed together to create the scene.
Therefore a single scene might contain dozens of individual shots. By splicing all of the shots together in the correct order you create the complete movie.
The VFX Process
Step 1: Scanning
Hollywood movies are typically shot on 35mm film at 24 frames per second. The first step of the visual effects process is deciding which of the shots need to have visual effects applied to them.
The rolls of film for these shots are then scanned, or digitised, in a hermetically sealed scanner room. Most reels are scanned at ‘2K’ resolution (2,048 x 1,556 dots per frame), an average VFX film may have around 150 shots, the ‘intermediate files’ for these 150 shots would consume about 1.5 terabytes of disk space.
Once it is digitised, a shot may go through a number of 3D & 2D artists. A big part of realistic computer generated effects is the creation of 3D models and characters and their integration into final composites by 2D artists.
3D Processes
3D Tracking The tracking department uses markers added to the scene to create a 3-D model of the scene and then a 3-D camera. The goal is for the 3-D camera to exactly mimic the motion of the real camera so that the 3-D elements added to the scene look right and move correctly as the camera moves in the actual scene.
3D Modelling A 3-D model is a collection of shapes that form the outside of the object being modeled. Most 3-D or CG creatures are formed from a combination of spheres, cylinders and other shapes that are molded on the computer screen into exactly the right configuration to look like the creature they are representing.
3D Setup Setup is the process of adding a "skeleton" of bones and joints to a 3-D model so that the different shapes in the model move correctly with respect to one another. In some cases the bones and joints are created by hand. In other cases they come from motion capture data.
Motion Capture To gather motion capture data, an actor is fitted with a suit that has reflective markers or lights at every joint. The actor moves on a special stage and 3-D cameras watch the actor from a number of different angles.
Computer software is then able to track all of the markers and, with the help of a technician, bind them together into a stick figure that accurately duplicates the motion of the actor. The stick figure is the bones and joints that then control and animate a 3-D model.
Mo-Cap Transformation
3D Animation In the animation process, an artist choreographs the movement of a 3-D character. Objects (models) are built on a computer (modeled) and 3D figures are rigged with a virtual skeleton. Then the limbs, eyes, mouth, clothes, etc. of the figure are moved by the animator on key frames.
2D Processes
2D Painting Painting is used extensively by any visual effects team. e.g. Create matte paintings for backdrops
Paint out wires, harnesses, brackets and other safety equipment Paint over the "holes" sometimes created by rotoscoping Touch up things like grass that has lawn mower tracks in it
2D Compositing Compositing is the process of adding all of the different layers (these layers are known as elements, or plates) of a shot together to create the final shot. The compositing artist incorporates all of the elements in the right order so they overlay each other properly to create the final shot. This is one of the most difficult aspects of the VFX process, as artistic training, technological proficiency, an understanding of cinematic conventions and an eye for detail are all required.
A visual effects team is responsible for all of the effects shots in a single film. At PHOTON, a team consists of a producer, several supervisors (for example a 3-D supervisor, a 2-D supervisor, etc.) and a number of artists. One of the first tasks for the team is the research and development process.
The team then uses what it creates during the R&D process to manipulate the shots it is responsible for. With the help of the supervisors and artists on the team as well as the film's director, the producer's job is to look at all of the shots, understand what the director wants to change in each one and then estimate the amount of time that all of the tasks will take.
A bubble plate from Ghosthip
The Technology
Digital visual effects at the Hollywood level require an incredible technology infrastructure that includes both hardware and software. The machine room pictures that follow shows just how extensive the hardware investment is. The team needs massive amounts of hardware for four reasons:
The scanned film and the different layers that the team creates require gigantic amounts of disk space. A single frame of a film, once scanned and stored on a disk, consumes on the order of 10 megabytes of disk space. All of the shots of "Ghostship" together consumed 1.6 terabytes of disk space.
Individual artists need high-end desktop machines to work on and render their individual models and layers. Pictured at right are the Silicon Graphics workstations used to power Flint, Flame & Inferno.
Rendering requires massive CPU resources. To render any animated 3-D figure or any effect like water or smoke, the CPU must generate millions of polygons, lines, points, etc and then light them correctly. And it must do this over and over again for each frame of the shot!
Compositing Compositing combines dozens of layers into a single shot. Because of the resolution involved -- millions of pixels and tens of millions of bytes per frame -- and the layering, both the CPU workload and the storage requirements are immense.
A thousand words...
The easiest way to understand what a visual effects team can do is to look at an example. The first example that we will use involves a surprising number of techniques to completely change the landscape from a wooded field to a seaside town! This is a shot from the movie "The Patriot." To get a feeling for the total transformation, take a look at these two short videos. The first shows the original shot as filmed. The second shows the scene as it appears in the movie:
Before & After This section of video is 20 seconds long, or about 480 frames.
Step by Step
First, a variety of things might be done to the original shot to clean it up, correct the color and so on. Since the camera pans across the scene in this shot, the next step is to build a 3-D model of the camera so that all of the visual effects the team will create will mesh with the original scene exactly
One of the first steps taken to add visual effects to the scene is the rotoscoping. An artist sits at a computer and, frame by frame, outlines the portion of the original shot that will be used in the final version. Rotoscopers are known within the industry as ‘Roto Dogs’, due to their relatively low place in the VFX food chain!
The breastworks, a portion of the field and several of the running soldiers will all be used, but the explosion seen on the left and everything else will be removed. The artist will outline these elements and create a ‘matte’ that can be used to create an empty space in a background scene. This allows a new object to be placed in the scene. Another camera crew has created an ocean shot. Once the ocean shot is cleaned up and color-corrected, it and the rotoscoped scene can be integrated:
Rotoscope Integration
Another artist in the paint department has been working on a matte painting of the town. This is a highresolution digital image created using a painting/ illustration package. Once the town is added in, the scene looks like this:
Town Integration
In this shot there are a number of boats encircling the town and firing on it. The boats are all computer generated. Each one is modeled and then added to the shot:
Boat Integration
The cannon fire for the boats is its own stand-alone effect that is created separately and then added to the shot. A variety of other effects are added to the shot, including things like smoke over the town, people in the town, a large explosion on the right, etc.
Cannon Fire
The final step in the process is compositing all of the different components of the shot (the rotoscoped foreground, the water, the town, people in the town, the boats, the cannon fire, the smoke, the explosion, birds flying overhead and so on) layer by layer to create the final shot as it will appear in the movie. Once digitally composited, the shot is written back to film so that it can be spliced into the movie.
Final Composited Scene
This brings us to the end of our topics for this semester. Next week we will be doing a lightning fast revision of the topics covered over the last 12 weeks. Make sure you make it next week as we will also have a general question time where you can clear up anything you are not quite sure about.
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