Many fans of the popular “Twilight” saga and its film franchise would like to maintain the illusion that the Cullens’ sparkling diamond-like skin is merely an unfortunate sun-induced vampire affliction, or that Taylor Lautner’s transformation into a werewolf in the film version of “New Moon” is a manifestation of a Quilete tribe member’s coming-of-age in a troubled, vampire-ridden world.

However, the mystical, supernatural feats depicted in the grossly popular “Twilight” movies, based on Stephanie Meyer’s novels, can be attributed to one equation that is applied each time a digital effect is added to a film:

O = A x M + B x (1 - M)

Or in other words, the over-composite image—the final cohesive shot one sees—is equal to a combination of two or more constituent images—digital and film stills—layered together.

On Wednesday, Eric Pascarelli, visual effects supervisor of Prime Focus VFX, and Matt Jacobs, visual effects supervisor of Tippet Studio, teamed up at the Museum of Science to deliver “Conjuring New Moon,” an explanation of the CGI effects responsible for Edward’s shimmering skin, Bella’s lovesick hallucinations, and the Quilete tribe’s werewolf transformations in the popular second film installment.

Pascarelli first explained the techno-genius behind “The Diamond Guy Effect,” the studio’s name for the glitter effect applied to Edward when he steps into sunlight. Pascarelli showed a video clip of Edward (Robert Pattinson), wracked with teenage angst, unbuttoned shirt framing his subtly painted abs. Over the sounds of screaming, excited fans mooning over Edward at the shooting, Pascarelli addressed the audience—a motley crew of middle-aged women and nerdy computer science high school students: “We based the glittering of his skin off of Thrassos marble,” Pascarelli said, as he replayed the clip of Edward’s shimmering, Greek-god like abs over, and over, and over again.

A complicated scheme of virtual manipulations creates the glittery CGI effect that simulates sunlight reflecting off Edward’s body. In Pascarelli’s video, Edward has black “tracking” dots applied all over his exposed skin, which the visual effects team later translated into a virtual mesh model of his body. The crew then used the mesh model to make a virtual wax model with a full-body cyber scan of Robert Pattinson as a guide. With a software program, they applied virtual miniature mirrors over the model, and introduced virtual suns—sources of light—into the frame. They recorded the reflections produced from the mirrors and super-imposed these reflections onto the real-time film of Edward, creating an over-composite image that matched the shape of his body.

“When we darkened his skin it looked like a skin disorder... this is more subtle,” Pascarelli said.

The CGI sleight-of-hand is also responsible for Bella’s visions of Edward—the apparitions emerge when Bella purposefully endangers her life, such as when she gets on the back of a biker-thug’s Harley, or when she jumps off a cliff. When Bella rides her own motorcycle, she hallucinates that Edward is following her. This scene is testimony to Stewart’s acting abilities: the motorcycle she was riding was nailed to a moving trailer, and when asked to “arbitrarily turn her head,” she panted longingly as she whipped her hair around. The visual effects crew then shot Edward on a green screen and projected his image onto a cloud of computer particles in the shape of a blurred candle flame so that he would seem more transparent. This effect also facilitated the illusion of Edward’s image blowing away into the wind, which was created with a nature-simulator that dispersed these “blurred candle” particles with a virtual breeze.

Matt Jacobs then described the process of creating horse-sized Quilete wolves: a combination of Timber wolves, Maned wolves, and elements of traditional werewolf lore. He wanted to stay true to “the special mythology of a wolf, [where] the wolf and the man spirits were combined, to protect his native lands, in this case from vampires.” The visual effects crew spent a few days observing Timber wolves at the Wolf Mountain Sanctuary in California to better understand their expressions, fur texture, gait, and other wolfy habits.

Modelers created a base mesh, or virtual model of the wolf, and puppeteers imbued the wolves’ nostrils, jaws, teeth, and ears with discreet, virtually-controlled commands so that animators could simulate wolf emotions (fear, submission, aggression, or the fervent yearning of unrequited love). The Tippett Studio invented a “proprietary fur tool” to generate the 4 million hairs on each wolf, and programmed each hair to randomly clump, rotate, vary in color, and simulate the effects of wind and movement.

The lecture exposed the two most beloved elements of the “Twilight Saga”: detailed full-body scans of Robert Pattinson and Taylor Lautner, and manifestations of Stephanie Meyer’s quixotic supernatural mysticism. A swoon-worthy cast and a genius visual effects crew are the reasons why “New Moon,” with a budget of only $50 million and less-than stellar critical reviews, has already grossed $704 million worldwide.

This article has been revised to reflect the following correction:

CORRECTION: February 10, 2010

An earlier version of the Feb. 9 arts article "'New Moon' Panel Unveils CGI Tricks" incorrectly stated the equation that was applied each time a digital effect had been added to the film "New Moon." The equation is O = A x M + B x (1 - M), not O = A x M + B x (1 x M).