Virtual camera system

A virtual camera system is a software tool used to control how a 3D virtual world is displayed.

In 3D video games, these systems manage one or more cameras to show the action from the best possible angle. They are especially important for providing a third-person view. A third-person view is a perspective rendered from a fixed distance behind and slightly above a player character. This viewpoint helps players see their avatar more clearly. It is very common in action and action-adventure games. Because these games use this perspective, they often use positional audio. This means the volume of ambient sounds changes based on where the avatar is located.

Creating these systems is harder than making a traditional film. Filmmakers can plan every single shot because the actors follow a script. However, virtual worlds are interactive and unpredictable. Developers cannot know where a player will move in the next few seconds. To solve this, the system must rely on rules or artificial intelligence. These tools allow the system to select the most appropriate shots automatically. Developers use various techniques to implement these rules. These include constraint solvers, artificial intelligence scripts, or autonomous agents.

There are three primary types of camera systems used in games. The first is the fixed camera system. In this setup, the camera does not move at all. Developers set the position, orientation, and field of view during the game's creation.

Because the views are static, the same location always looks the same. This allows designers to use cinematic language to create a specific mood. Some games using this system, like early Resident Evil, use tank controls. This lets players move the character relative to themselves rather than the camera. This helps the player stay oriented when the camera angle changes.

The second type is the tracking camera system. These cameras follow the character's movements from behind.

This was very common in early 3D games like Crash Bandicoot or Tomb Raider. It is simple to implement because the player does not control the camera. However, it has several technical issues. The view might be occluded, meaning an object blocks the sightline. The camera might also jerk or move into awkward positions when a character turns or stands against a wall.

The third type is the interactive camera system. These systems are partially automated but allow the player to change the view.

While the camera still tracks the character, the player can change its orientation or distance. On consoles, players often use an analog stick for this. On a PC, they usually use a mouse. Super Mario 64 was one of the first games to offer this. It used an AI-driven tracking camera that could anticipate movements. For example, it would look toward a turn before the player reached it. Some games, like Super Mario Sunshine, can be difficult because of the camera control. Others, like The Legend of Zelda: The Wind Waker, are described as being very smart.

To make these cameras work, developers use a constraint solver. This software generates the best shot based on specific visual constraints. For instance, a developer might request a shot where a character covers at least 30 percent of the screen space. The solver then calculates the necessary coordinates and rotation for the camera. If it cannot find a perfect solution, it may relax the constraints. It might ignore the screen space rule and simply zoom out to ensure the character is visible. Other systems use scripts to handle "film idioms," which are common scenarios like a conversation. A script can trigger a sequence of over-the-shoulder or close-up shots automatically.

Virtual cameras also have uses in mixed-reality and motion capture. In 2010, Microsoft released the Kinect, a 3D scanner and webcam hybrid. Researcher Oliver Kreylos used the Kinect to allow free-viewpoint navigation in virtual scenes. He even combined two Kinects to enhance the video capture. In motion capture, a director can use a virtual camera rig to see digital characters move in real time. This rig includes a monitor, motion sensors, and sometimes joysticks. Resident Evil 5 was the first game to use this technology. It was originally developed for the 2009 film Avatar to allow directors to move intuitively through digital environments.