The Process Behind Centropolis FX's Visual Effects

Understanding Effects

Founded in 1996, CFX now employs over 100 professionals specializing in digital visual effects for numerous Hollywood films. Their team of artists, technicians, producers, and managers collaborates to craft scenes that are breathtakingly realistic and utterly immersive for viewers.

The term digital in digital visual effects highlights CFX's reliance on computer technology to produce its effects. In the industry, this is often referred to as CG, or computer-generated. Artists might say, "That scene is entirely CG," or "Those soldiers are all CG," or "Only the actors are real; the rest is CG." CG effects bring fantastical characters like Godzilla to life and have largely replaced traditional model-based effects. The benefits of CG include unparalleled realism, adaptability, and cost efficiency compared to older methods.

CFX collaborates closely with the film's director both during production and post-production to craft visual effects. Their involvement during filming aids the director in making creative choices, ensuring seamless integration of effects. CFX also adds markers and features to scenes to simplify post-production. For instance, cameras may be equipped with encoders to facilitate the incorporation of effects. In post-production, the director and CFX work meticulously to perfect the look of each effect in the film.

CFX employs a wide range of tools and methods to produce visual effects. The company's capabilities include:

When combined, these techniques empower the visual effects team to bring nearly any director's vision to life. It’s an extraordinary toolkit!

An Example

To grasp the capabilities of a visual effects team, let’s examine an example. This example, taken from "The Patriot," showcases a variety of techniques used to transform a wooded field into a coastal town.

To appreciate the full extent of this transformation, watch these two brief videos. The first displays the original footage as it was filmed, while the second reveals the final scene as seen in the movie:

The footage arrives on film, and the first step is to digitize it for manipulation. Each frame is scanned individually (movies are filmed at 24 frames per second) and stored as a high-resolution, full-color image measuring 2,048 by 1,556 pixels. The 20-second clip shown in the videos consists of approximately 480 frames.

Initially, the original footage may undergo several adjustments to enhance its quality, such as color correction and cleanup. As the camera pans across the scene, the team constructs a 3-D model of the camera's movement to ensure all visual effects align perfectly with the original shot.

Rotoscoping is one of the first steps in adding visual effects. An artist meticulously outlines, frame by frame, the elements from the original shot that will remain in the final version. This includes the breastworks, part of the field, and several running soldiers, while removing the explosion and other unwanted elements. The artist effectively extracts these components from the frame.

A separate camera crew has captured footage of the ocean, conveniently located near CFX's Hollywood studio. After cleaning and color-correcting the ocean footage, it is seamlessly integrated with the rotoscoped scene:

This video demonstrates the field being replaced by water.

An artist from the paint department has been crafting a matte painting of the town. This high-resolution digital artwork is produced using advanced painting and illustration software.

Once the town is incorporated, the scene transforms into this:

This video illustrates the town seamlessly integrated into the shot

In this scene, numerous boats surround the town, firing upon it. These boats are entirely computer-generated. Each vessel is meticulously modeled and then inserted into the shot:

This video displays the boats on the water

The cannon fire from the boats is a distinct effect, created independently and later integrated into the shot.

This video illustrates the cannon fire from the boats

Numerous additional effects are integrated into the shot, such as smoke billowing over the town, townspeople, a massive explosion on the right, and more.

The final stage is compositing, where all elements of the shot—rotoscoped foreground, water, town, townspeople, boats, cannon fire, smoke, explosions, birds, and more—are layered together to form the final scene. Once digitally composited, the shot is transferred back to film for inclusion in the movie.

This video montage showcases all the effects

The small images here don’t fully capture the shot’s grandeur. When viewed on a large theater screen in "The Patriot," the intricate details added to achieve realism become strikingly apparent.

Creating such a scene is incredibly time-intensive. Although the shot lasts only 20 seconds, hundreds of hours are dedicated to crafting a detailed and believable visual. In this video, artists involved in the shot discuss the time invested. This intricate process, involving an entire team, may be repeated hundreds of times in a single film. In "The Patriot," 150 shots feature these elaborate visual effects.

Overview of the Visual Effects Process

A standard movie can consist of 1,000 to 1,500 shots, ranging from one or two seconds to 30 or 60 seconds in length. In "The Patriot," the longest shot handled by the team was approximately 1,000 frames. Scenes are often filmed with multiple cameras to capture wide angles, close-ups, and varying perspectives. These shots are later combined to form the final scene, which may include dozens of individual shots. Arranging these shots in the correct sequence creates the complete film.

Hollywood films are typically shot on 35mm film at 24 frames per second. The initial step in the visual effects process is identifying which shots require effects. For "The Patriot," 150 shots needed visual effects. The film rolls for these shots are sent to CFX for scanning using a Kodak Cineon scanner, capable of up to 4,096 dots of resolution (4,096 x 3,112 per frame). "The Patriot" was scanned at 2K resolution (2,048 x 1,556 per frame), with the 150 shots and intermediate files occupying roughly 1.6 terabytes of storage.

After digitization, a shot may pass through several 3-D artists. A key aspect of realistic computer-generated effects is the creation of 3-D models and characters, which involves multiple steps, including:

A visual effects team oversees all effects shots in a film. At CFX, the team includes a producer, several supervisors (such as a 3-D supervisor, a 2-D supervisor, etc.), and numerous artists. One of their initial tasks is research and development. For instance, during "The Patriot," significant R&D effort went into creating realistic soldiers and groups of soldiers for scenes. The team then applies these R&D outcomes to manipulate the shots they handle. This process is time-intensive, with a film typically taking about a year to complete.

The producer, alongside supervisors, artists, and the film's director, reviews all shots, identifies the director's desired changes, and estimates the time required for each task. These estimates form a detailed production schedule, often created using tools like Microsoft Project, which the team follows meticulously.

The Technology

Creating digital visual effects at a Hollywood standard demands a robust technology infrastructure, encompassing both hardware and software. The machine room at CFX highlights the significant hardware investment required. The team relies on extensive hardware for four key reasons:

This makes the machine room at CFX a truly remarkable space!

This brief video tour of the machine room provides a glimpse into the extensive equipment required for CFX's operations.

The backbone of CFX's operations is a set of SGI Onyx machines. These systems feature multiple processors and advanced graphics pipelines, accelerating rendering and compositing tasks. Compositing artists typically use an Onyx as their primary workstation, while other artists utilize them for background rendering. Additionally, a Linux render farm, composed of numerous PC desktops, collaborates to divide and execute rendering tasks efficiently.

Example 2

A significant aspect of "The Patriot" revolves around its battle scenes, many of which feature computer-generated soldiers. A substantial portion of the R&D effort for this film focused on designing individual soldiers and groups that would appear realistic and believable on screen.

Designing computer-generated soldiers that appear realistic on the big screen is challenging, as the human eye easily detects repetition and unnatural movement, even from a distance.

To develop lifelike groups of CG soldiers, the CFX team began with real actors experienced in revolutionary war reenactments. These actors were equipped and filmed on a motion capture stage. The captured data enabled the team to generate stick figures performing various realistic actions—walking, loading guns, falling, and more. For instance, this video displays motion capture data of four soldiers engaged in different activities.

The team enhanced these stick figures with 3-D soldier models, creating four distinct variations (for both armies) with differing heights and builds:

These soldier models were animated using the motion capture data and then organized into groups.

These two videos illustrate the process:

A significant aspect of the project involved "dressing" the soldiers, achieved by texture-mapping various fabrics and equipment onto the 3-D models. In "The Patriot," since CG soldiers are viewed from a distance, advanced features like cloth dynamics and facial expressions were unnecessary. Including these would have significantly increased the computational load, which was already substantial due to the number of soldiers.

The following shot illustrates how groups of soldiers are incorporated into a scene. Here is the scene as originally filmed:

This video shows the scene as it was filmed.

Upon close inspection, you’ll notice several bushes in the distant field and even lawn mower tracks in the foreground grass! The visual effects for this scene included altering the sky, reworking the grass, removing the bushes, and adding two armies. The following images illustrate the process.

This video demonstrates the addition of one group of soldiers to the shot.

This video displays the shot as seen in the movie.

These compressed MPEG files cannot capture the richness and depth of the final scene as it appears in theaters, nor do they convey the realism of the two armies. Witnessing the scene on the big screen is truly breathtaking!

Example 3

This example demonstrates how a film director can completely alter a scene using computer-generated effects. In this instance, the crew filmed a scene on a street in Charleston, SC.

This video shows the scene as it was filmed. The actors wore period-appropriate costumes, and the street was covered with dirt to conceal the asphalt and create a historical setting. Compare it to this video of the final scene as it appears in the movie — the transformation is remarkable!

The director decided to completely change the end of this shot. Instead of buildings lining the left side of the street, the director envisioned a dock, as shown here:

To achieve this effect, CFX first used rotoscoping to extract the actors and the wall from the original shot:

A new sky was incorporated to serve as the backdrop for the transformed scene:

Models of the docked boats were filmed against a green screen, rotoscoped, and then integrated into the shot. Additionally, several buildings (both real and CG models) were added on the right:

Crates and barrels were placed on the dock to add detail, and a new cloud was even added to the sky above the buildings:

CG flags were designed and attached to the ships:

All these elements combine to create the final image:

These videos provide fascinating insights:

A transformation like this demonstrates the extent to which a director can shape the look and feel of a scene. Approximately 90% of the scene differs from the original footage. CFX's magic lies in its ability to collaborate with the director to craft entirely new realities that appear utterly convincing on screen. The effort required to achieve this level of detail is immense, but as seen in films like "The Patriot," the results are truly breathtaking!

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