Class Name: Camera Point

Superclass - Point Geometry

Definition

An eye point to view from, specifying a location, an orientation, and either an orthographic or perspective viewing volume. A viewing volume is defined, oriented along the axis defined to start at the camera Location 3D and to go in the direction of the specified orientation. This orientation defines the coordinate space of the camera, where the camera is at (0,0,0) and is oriented to look down the +Y axis (assuming the XY plane defines the horizontal plane and the right-hand rule applies). If the camera defines an orthographic view point, then the viewing volume is the volume between two parallel rectangles, defined with coordinates of (left,bottom) to (right,top). The first rectangle is (near) meters away from the camera location, and the second rectangle is (far) meters away from the camera location. If the camera defines a perspective view point, then the viewing volume is a viewing frustum that can be described by in one of two ways. The perspective viewing volume can be defined as the volume starting at the (left,bottom) to (right,top) rectangle located in the near clipping and expanding to the far clipping plane. Or the perspective viewing volume can be described by a field-of-view angle, an aspect ratio that is the width of the frustum divided by its height, and the distance to the near and far clipping planes.

Primary Page in DRM Diagram:

• 5

Example

1. A perspective viewing point defined at the beginning of a runway, oriented to look down the runway.
2. An orthographic viewing point defined high above the transmittal, in the center of the transmittal, to give a "God's eye view" of the entire transmittal.

FAQs

What are Camera Points used for?

Camera Points are typically used for pre-set views into a transmittal. They can also be used for eye point attachments for own-ship Models.

Constraints

• No Attribute Conflicts
• Non Crossing Aggregations
• Non Cyclic Aggregations
• Precedence of Attribute Set Index
• Color Mapping Restrictions
• Image Mapping Functions and Texture Coordinates
• Nested Primitive Geometry
• Non Nestable Continuous LOD
• Valid ID Field

Composed of (one-way)(inherited)

• optionally, some {ordered} Attribute Set Indices
• optionally, a Classification Data
• optionally, some Property Tables
• optionally, some Property Table References
• optionally, some Property Values
• optionally, some Tack Points
• optionally, some {ordered} Colors
• optionally, a Light Rendering Properties
• optionally, a Rendering Properties
• optionally, some {ordered} Image Mapping Functions
• optionally, a Rendering Priority Level
• optionally, a Conformal Behavior
• one Location

Composed of (one-way)

• optionally, a World 3X3 (notes)
• optionally, some {ordered} Rotations (notes)

Composed of (two-way)(inherited)

• optionally, a Union of Primitive Geometry
• optionally, a Geometry Node

Composed of (one-way metadata)(inherited)

• optionally, a Time Constraints Data

Component of (two-way)(inherited)

• one or more Union of Primitive Geometries

Field Elements

Notes

Composed of Notes

World_3X3

 if present, used to determine the camera point's orientation
 (either a World_3X3 or a set of ordered Rotations could be
  present, but not both).

Rotation

 if present, used to determine the camera point's orientation

Fields Notes

ID

 ID required to be unique from all other Camera Point object IDs.

projection

 Either orthographic or perspective

camera_near

 Distance from camera position to near clipping plane, in meters.

camera_far

 Distance from camera position to far clipping plane, in meters.

use_left_right_bottom_top

 If true, then use the parameters from the left, right, bottom, and top
 fields.  These fields are always used for Orthographic viewing, but
 Perspective viewing can either use these fields or the field-of-view
 and aspect ratio fields.

left

 the X coordinate of the lower left corner of the rectangle in the near
 clipping plane

bottom

 the Y coordinate of the lower left corner of the rectangle in the near
 clipping plane

top

 the X coordinate of the upper right corner of the rectangle in the far
 clipping plane

right

 the Y coordinate of the upper right corner of the rectangle in the far
 clipping plane

horizontal_fov

 angle, in degrees, of the horizontal field of view.  Used for
 perspective viewing if the use_left_right_bottom_top flag is false.
 This assumes a on-axis symmetric viewing volume.  Off axis viewing
 volumes are not supported.

aspect_ratio

 the width of the frustum divided by its height. Used for perspective
 viewing if the use_left_right_bottom_top flag is false.