How is gravity taken?

Overview of gravity production process;

In the gravitational outer space scene, only the face of the actor under the helmet is actually photographed, which makes the film more memorable technically and aesthetically. Everything else in the outer space scene, including the spacesuit, the space station and the earth, is made by CG. Similarly, in one scene, Si Tong floats on a spaceship without a spacesuit. Brock is hung on the set by a steel wire, and her surroundings are digitally made. Most of the scenes in the space station were shot in the scenery.

Gravity is a very complicated project, which integrates virtual and real images in a very creative way. The following is a general summary of the production process of this film. Paul Beilby, CG lighting director of Framestore, Michael Dillon, senior producer of Technicolor, and other members of the team provided these details.

1. Trajectory Design-Frame Storage

Cuarón and Framestore worked out the trajectory of the earth in the film, which will determine what the earth looks like in the film.

2.Previs-frame storage

Cuarón and Lubezki collaborated with a group of animators to produce a low-resolution animation preview of the film. Contains virtual camera motion.

3. Pre-lighting Design-Frame Store

Lubezki cooperated with a group of technical directors to design the lighting effects and CG assets of each virtual scene in the movie, and optimized it for quick rendering and feedback.

4. pre-DI

Cuarón, Lubezki, digital color director J.Scott and visual effects director Tim Webber used two independent and accurately calibrated DI cinemas, one in Los Angeles and the other in London, to optimize the color matching scheme of four clips in the film and work in real-time environment. The color matching result is output (sometimes just one frame) and sent to Framestore as a reference picture for the final lens visual effect.

5.Techvis-frame storage

Previs and previous lighting design data will be used to set camera trajectory and lighting parameters, thus simulating the subjective perspective of each character in the film.

6.LED light box real shot-Shepperton

Techvis data is processed in the field to control the dynamic lighting in Motion Controll and LED light boxes. Lubezki adjusts the LED image illumination and uses artificially controlled hard light to simulate the sun. Adjust the camera speed to match the actor's performance.

7. Take a real shot with a robotic arm-Shepton

Techvis data are processed on site so that the manipulator can move around Bullock to simulate the zero-gravity environment in the space capsule. The lighting in this part is the same as that in traditional shooting.

8. Traditional live shooting-Shepton

Most of the shots in the capsule and a 65 mm scene on the earth have been polished and shot in the traditional way.

9. Alignment and Presentation-Frame Storage

A animators and bookbinding machines refer to real shooting data to make animations of characters wearing spacesuits and aircraft.

B. Modelers make high-quality models based on Previs assets.

C. Visual development technical guidance and texture artists make material patterns according to NASA photos and material samples.

10. Integrating real shots and CG elements -Framestore

A. The typesetter obtains the real shot material and sets it according to previs. Many animators, animation directors, biological special effects directors and technical directors work together to produce the final CG animation and lens action according to the actors' performances.

B. The lighting technical director cooperates with the company's internal visual effect director and lighting director to light the CG scene to ensure that it matches the real shot material.

C. The compositor, together with the visual effects director and the compositing director, synthesizes the real shot material with the CG picture to make the final picture, and then submits it to Cuarón and Lubezki for review and fine-tuning.

1 1. Color mask extraction -Technicolor

Get the 2D file made by Framestore, add an external mask, and color each important element in the picture independently.

12.DI color matching technology

Scott, together with Lubezki and Cuarón, specified the color of the 2D image and used a multi-layer dynamic mask. The final output version will be used for 2D DCP, Kodak Vision 2383 copy and HD master.

13. Stereo transformation-mainly focusing on film and frame storage.

Prime Focus transforms the real shot material and some visual elements into 3D, and Framestore transforms other parts of the movie.

14. 3D color matching-color

The production team decided to output two brightness versions for 3D white screen and IMAX 3D giant screen projection, respectively, to ensure that the brightness can reach 4.5fL and 7fL. As a part of this process, they selectively carried out anti-dark angle processing to make up for the "hot spot" problem caused by the projection of RealD metal curtain.

God's innovation:

No. 1: giant light box

The first shot of the film is a 7-minute long shot. In a vast space, it is easy to forget that these shots are impossible to shoot. Unless, the film crew is really shooting in the vast space. So, how was it filmed? The truth is that the whole shooting process of Gravity is an unprecedented innovation.

Many times, shooting is done in a light box with a height of 6 meters and a width of 3 meters. There are as many as 6.5438+0.8 million LED lights in this "space light box", which looks no different from the big screen commonly used in concerts, but each one can be controlled separately. No matter where the actors are, no matter how fast they move, the light box can show their surroundings. The advantage of this is that, in addition to giving the audience a sense of reality, the actors will no longer have the false feeling of performing in front of the green screen by imagination.

Second: puppet rope

In order to better reflect the weightlessness of astronauts, this time it is different from shooting space movies in the past. This time, no large props were used to simulate the space capsule, and Sandra was not needed. Brock only needs 12 steel cables to be locked in a "weightless room" ―― they hung the actress like a marionette and made her roll, hang upside down or even lie flat in the air, which violated gravity. Simply put, it is "where there is gravity, you can feel that there is no gravity." Of course, there must be a group of technicians with high-tech skills behind this.

Third: aircraft

There are quite a few shots in which actors "fall" or even "smash" out of control. In fact, the actor basically did not move, but moved a dynamic camera tailored for the film-this effect can be achieved by "smashing" the camera at the actor. Of course, whether a person hits a machine or a machine hits someone, it hurts people too much, so in many cases, only the actor's face is real in the lens, and the other parts of the body are made by computers.