Real Time Visual Effects for the Technical Artist

Chris Roda

• Publisher: CRC Press
• Year: 2022
• ISBN:
  9781000551570
• Edition: 1
• Topic: Informatique
• Subtopic: Infographie

Visual effects (VFX) are one of the most complicated components of feature film and television creation. With advancements in such technologies as Ray Tracing and Virtual Reality, the visual quality of the real-time rendering engine is now rivaling feature film. Real-time rendering requires years of programming experience with advanced understanding in math and physics.

As the power of the real-time rendering engine improves, so too do the interfaces for VFX creation. With limited technical understanding, artists can create VFX with the push of a button and tug of a slider. As powerful as the interfaces are, they can only expose a portion of the true potential of the rendering engine. Artists are limited by their understanding of the engine interface. Real Time Visual Effects for the Technical Artist is written for digital artists to explain the core concepts of VFX, common in all engines, to free them from interface bounds.

Features:

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• Introduces the reader to the technical aspects of real-time VFX

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• Built upon a career of more than 20 years in the feature film VFX and the real-time video game industries and tested on graduate and undergraduate students

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• Explores all real-time VFX in four categories: in-camera effects, in-material effects, simulations, and particles

This book is written to complement undergraduate- or graduate-level courses focused on the fundamentals of modern real-time VFX.

Chris Roda is a Technical Art instructor at the Florida Interactive Entertainment Academy (FIEA), a graduate degree program in interactive, real-time application development at the University of Central Florida. Early in his career, Chris was a visual effects artist in the film and television industries where he contributed visual effects for films such as Spider-Man, Titanic, and The Fifth Element. Before coming to FIEA, Chris was a CG Supervisor at Electronic Arts, where he worked on video game titles such as NCAA Football and Madden NFL Football. In addition to teaching, Chris works on generating tools and pipelines for the creation of immersive experiences: the amalgamation of the narrative of films, the interactivity of video games, and the immersion of theme parks.

Chapter 1 What Are Visual Effects?

DOI: 10.1201/9781003009795-2

Introduction

When considering the components that make up the real-time production process, visual effects are the most difficult to define. For brevity, instead of defining all that visual effects are, it may be easier to identify what visual effects are not. Within any computer-generated scene, the participant will find multiple familiar items: environments, animated characters, and props. Artificial environments define the story world’s settings, bounding what is conventional. They introduce the participant to what is typically expected or what is plausible for the scene. Characters are animated from keyframes or from motion capture. They interact with the environment and other characters. Props are passive objects with which both characters and environments act upon. Visual effects are everything else found in that story world. When a component is not considered an environment piece, an animated character, or prop, it is a visual effect (Figure 1.1).

FIGURE 1.1 Visual effects in the computer-generated scene.

Visual effects are the lighting that make a forest look foreboding in the middle of the night and enthusiastic in the morning. They provide the camera flares in the early sun and make the world appear blurry in times of obscurity and confusion. Visual effects are what make static objects appear as if they are moving, such as barber poles or wind-blown foliage, and make water appear to be flowing and rippling. They generate dramatic destruction such as collapsing buildings and the subtle bounce of a princess’s hair as she rides her horse. When not captured as on-set special effects, visual effects provide rain, snow, smoke, fire, and rainbow-colored pixie dust from magical wands.

Generating emotional impact is a primary objective of the computer-generated pipeline. Skillful writing and compelling performances drive computer-generated imagery (CGI) characters to interact with their environments and props to create memorable visual experiences. Visual effects complement these fundamental components and influence emotional mood and tone. They make dire situations feel more dreadful and happy situations more festive and alive. They make mundane events feel like epic, destiny threatening circumstances. Visual effects complement and supercharge scene components to create emotionally driven adventure.

Real-time environments can be anything from the mundane to the outrageously unbelievable. They may represent any moment in time from the present to the ancient past and to the unforeseeable future. Environments may take place underwater, within outer space, or in alien worlds. Visual effects make these settings feel real, natural, and believable. They add credibility to their surroundings making them feel as if they have always existed.

Story world credibility is threatened when alien beings or fantastic creatures are introduced. Foreign characters are thematically integrated with familiar settings through the exchange of visual effects techniques. For example, consider a frog demon summoned by an evil wizard to wreak havoc on a medieval hamlet. Simply introducing the character into the environment without the aid of visual effects feels artificial and cheap. Adding visual effects makes the demon creature, although very alien, feel natural within the experience. The lights of the village illuminate the demon while the fire in its eyes illuminates itself as well as its immediate surroundings. The lighting in the town casts shadows onto the demon and conversely, the demon casts shadows back onto the environment. When the demon collides with scene objects, they are damaged or destroyed. When the demon lumbers by, it leaves footprints kicking up dirt and sand. The creature spits slime and soaks the surroundings and all who come within immediate contact. The exchange of visual effects integrates alien components within familiar environments.

Visual effects take an ordinary experience and make it larger than life. They push the experience from the real to the hyper-real. Very rarely do the events of real-life match the emotional impact generated by the same situations. Instead of displaying what is real, visual effects create the story world constructed by our emotions. Visual effects push the impact of natural phenomena to the catastrophic. They add vibrant colors and brilliant lighting to otherwise mundane situations. Visual effects make reality conform to the emotional stories created with our imaginations.

From a pure commercial perspective, visual effects are the components added to an experience to cue the audience something special or wonderful is occurring. This is the extra icing on the cake, the extra polish to the scene, or the extra glitter to the gold. Visual effects appeal to the curiosity and invite outsiders to participate within the offered story world.

Visual effects are diverse. They can be anything from the lighting that controls the scene’s emotional mood and tone to the shapes a frog morphs while transforming to a prince. They can be the dark clouds that roll on to a field of battle to the armies that lob projectiles at each other. Visual effects can be the blood and destruction spilt on the battlefield as well as the foliage that grows and replaces them. Instead of replacing characters, props, environments, and their animations, visual effects complement these components within their thematic story worlds.

Visual Effects Are Animations

All visual effects are animations. The visual effects industry evolved from animation. All original visual effects artists were former animators or had mastery of the 12 principles of animation. Visual effect images need to move and change over time; otherwise they are simply pretty pictures. This condition even covers lighting and post-processing which may not appear to change. Over the course of an experience, they can and often do change. The contrast of the same scene between two different contexts has a dramatic impact on the experience’s emotional mood and tone.

Special Effects

There is an important distinction to be made between visual effects and special effects. While visual effects are important components of the CGI production pipeline, “Special Effects” is a live-action production term reserved for phenomena requiring unique attention. Usually mechanical in nature, these phenomena may include mechanized props and scenery, scale models, animatronics, pyrotechnics, and atmospheric simulations such as physical wind, rain, and snow. Examples of mechanized props are exploding toilets, collapsing stages, and imploding buildings.

Special effects also include prosthetic makeup that makes actors look non-human. These include any mask or prosthetic that moves or behaves in an unnatural way.

Before the evolution of computer visual effects, all optical effects were considered as special effects. These phenomena were manipulated after primary image capture and were considered as part of the “in-camera” process. Source images were transferred from source film to destination film using optical printers, mattes, and other multiple exposure techniques.

Computer-generated imagery originated as a subsection within special effects and evolved into its own area of specialization. Now, any imagery created or manipulated in post-process using a computer is considered as a visual effect while any phenomena captured concurrently with live footage is considered a special effect.

Off-Line Visual Effects

Any special effect captured or manipulated after primary exposure and before final coloration was considered as part of the “in-camera” process. These were also called “off-line” effects because the techniques were performed away from the expensive on-set production process. These effects included optical effects, models, and miniatures which were filmed and optically integrated with source footage. Being off-line meant extra time and attention could be devoted to the special effects without impacting or delaying primary production.

Computers were originally used to assist with the off-line filming of models and miniatures. Computer motion-controlled camera rigs generated impossibly complex camera movements and multiple camera passes which duplicated camera movements with every iteration. Different camera passes were filmed under different lighting conditions to generate mattes and isolate diffuse, shadow, and highlight information layers. Computers were also used for assembling these layers during optical printing.

Three-dimensional CGI was first used in the 1976 film, Futureworld. Used sparingly afterward, the use of CGI gained significant attention in the 1982 films Tron and Star Trek II: The Wrath of Khan. Other landmark films such as The Last Starfighter, Young Sherlock Holmes, The Abyss, Terminator 2: Judgment Day, and Jurassic Park contributed CGI to evolving into a significant special effect technique. CGI continued to replace optical special effects until evolving its own visual effects category.

The 1995 film Toy Story became the first full CGI film. Instead of providing only special effects components, computers were used for generating all visual production content. This landmark event initiated a transition of many animated films from hand-drawn to computer generated. While computers are still used for generating CGI films, the process is still relatively slow. This limitation is changing radically.

In this book, the term off-line refers to all CGI production performed after original source exposure and before final coloration. While this term applies to all live-action visual effects, it also describes the production process for CGI-animated films. Being off-line frees artists from generating frame-rate dependent images, allowing focus on qu...