Camera Types

This document describes the camera types that can be created and edited using CreativeStudio.

Note: Cameras created with other 3D graphics tools can also be loaded into CreativeStudio.

Camera Control Methods

This section describes the types of camera control methods that can be set as the mode in the View category of the camera Properties panel in CreativeStudio.

Aim

In the Aim method, the look-at point is used to control the view direction of the camera. You can set the position, the look-at point and the twist.

Table 1. Parameters that can be set in Aim mode

Item Description
Position Sets the camera position in world coordinates.
Look-at point Sets a point in front of the camera used to control the view direction of the camera.
Twist Sets the rotation angle with respect to the camera's view direction in camera coordinates. Counterclockwise represents the positive direction.

Fig. 1 Camera control axis when using Aim method

Aim method

LookAt

In the LookAt method, the camera is controlled not only by the look-at point, but also by moving the position of a control point that is always located above the camera.

Table 2. Parameters that can be set in LookAt mode

Item Description
Position Sets the camera position in world coordinates.
Look-at point Sets a point in front of the camera used to control the view direction of the camera.
UpVector Controls the camera rotation angle by moving the position of the UpVector control point located above the camera.

Fig. 2 Camera control axis when using LookAt method

LookAt method

Rotate

In the Rotate method, the camera is rotated to control the view direction of the camera. You can set values for Position and Rotation.

Table 3. Parameters that can be set in Rotate mode

Item Description
Position Sets the camera position in world coordinates.
Rotation Sets the camera rotation angle in camera coordinates.

Fig.3 Camera control axis when using Rotate method

Rotate Method

Projection Types

This section describes the area viewable by the camera and ways in which it can be viewed.

The term projection refers to the different ways of handling the coordinate system for what the camera views.
There are two projection types -- perspective projection camera (Persp) and orthogonal projection camera (Ortho) -- and different items can be set for each.

Perspective Projection Camera (Persp)

The term perspective projection camera refers to a camera where perspective is applied based on the camera angle. When perspective projection conversion is used, objects closer to the camera look larger, while objects farther from the camera look smaller.

To read details about the perspective projection conversion, see here.

Table 4. Parameters that can be set with the perspective projection camera

Item Description
Fovy Sets the angle in the Y direction.
Aspect Specifies the horizontal and vertical aspect ratio of the area viewable by the camera that results from dividing the horizontal width by the vertical height.

Orthogonal Projection Cameras (Ortho)

The term orthogonal projection camera refers to a camera that does not depend on depth information or perspective effects based on the camera angle. These are also called ortho cameras. Although coordinates are converted to window coordinates just as with a perspective projection camera, horizontal and vertical values are used unchanged.

Table 5. Parameters that can be set with the orthogonal projection camera

Item Description
Aspect Specifies the horizontal and vertical aspect ratio of the area viewable by the camera that results from dividing the horizontal width by the vertical height.
Height Sets the height of the area viewable by the camera (clipping volume).
The width is calculated automatically based on the Aspect specification.

Clipping in the Depth Direction

The term clipping refers to a polygon clipping process performed on polygons that straddle the area viewable by the camera (called the "clipping volume") in the clip coordinate system. This is set for both perspective projection and orthogonal projection cameras.

Table 6. Near clip and Far clip

Item Description
Near Specifies the distance to the near clip plane of the clipping volume in camera coordinates.
Far Specifies the distance to the far clip plane of the clipping volume in camera coordinates.

W Buffer

The term W buffer refers to the memory buffer in which W values used in the clip coordinate system are stored during the rasterizing process.

Depth tests using the value in the W buffer are possible by specifying a value other than 0.0 for W scale.

The formula for finding depth values in window coordinates by using the W buffer is given below.

Window coordinate system depth value = - (Z value in clip coordinates ÷ Value specified for the far clip)

As for the relationship between the fragment depth value before perspective projection conversion and the depth value stored the depth buffer, the figure below shows the status of the W buffer before and after use.

w scaling

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