Avatar: The Way of Water (2022) was launched about two months ago and has been spotlighted for its realistic image effects. It costs more than two billion dollars to make, and hundreds of companies participated to produce VFX (visual effects). It is evaluated that it cultivated the ground of CG (computer graphics) which had not been observed. More than ten million people in Korea watched this movie despite the inflation of movie tickets, and its fancy visual beauty raised attention to CG technologies again. Especially, more than half of the audience visited special theaters such as 3D or IMAX, which means people particularly noticed the visual aspect. So, what is CG and what technologies are used for this?
 The term ‘CG’ was first used by a researcher of Boeing, William Fetter, referring to a cockpit described by computer coordinate device as ‘Computer Graphics’. Initial CG was used by the government or research centers and also used by the military. Then it began to break into the broadcast industry and developed as video graphics, and finally essential movie technology. The CG is performed based on the CPU and today’s CG utilizes GPU, showing much more advanced image quality.
 The CG should implement scenes that cannot be seen in reality as if it looks genuine. It needs high-performance computers to display various situations such as fluids and explosions, while obeying physical laws and mathematics. Specifically, movies like Avatar 2 have a lot of scenes including water, and differential equations are actively applied to reproduce the flow of oceans which cannot be actually filmed.
 It is used to implement virtual scenes as described above, but CG is also added to real scenes to enrich them. After attaching sensors that convey motion information to the computer to actors’ faces and bodies, it is changed into a CG image by picturing them with a camera; this method is called “motion capture”. Special characters such as animals and aliens are composed of real actors using this technique.
 In the last decade, beyond this motion capture technology, a CG technique that can capture actors' facial expressions and eyes lively, has been developed. It does not just track the sensor but captures actors' facial changes by wearing a device on which subminiature cameras are embedded toward the face. It allows making not only virtual characters but also keeping the actors' live facial acting.
 In Avatar 2, the above technologies are utilized complexly, and most of the scenes are filmed in real water, not just using typical mathematical CG. Because the camera for CG had to work well even underwater, methods like preventing the reflection of light and introducing a dual capturing system were applied. The film director of Avatar 2, James Cameron, said that it took more than a year to overcome optical problems faced during the underwater filming.
 These CG technologies are expected to achieve greater growth with the recent rapid development of computers. Numerous advanced computers are needed to process all the images with increased qualities and high scanning rates for smoother screen transitions. As supercomputers appear with high computational power with the help of GPU, they have adopted to the movie requiring much CG processing. Wētā FX, one of the main producers of Avatar 2, also expressed that they would be able to provide much more enhanced CG technologies in the follow-up series.