Class Name: Stamp Behaviour

Superclass - <SEDRIS Abstract Base>

Subclasses

Definition

An instance of this DRM class specifies that the <Geometry Hierarchy> instance of which the <Stamp Behaviour> instance is a component rotates automatically with the viewpoint of a a 3D graphics application at the time that the environmental object assigned the <Stamp Behaviour> instance is rendered, attempting to continually face the viewer.

The <Geometry Hierarchy> instance rotates about the u, v and/or w axes, within the specified angular limits. The centre of rotation is specified by the <Location 3D> component. The axes are positioned at the centre of rotation, aligned with the equivalent SRF axes. Geometry with a <Stamp Behaviour> instance is normally planar in nature and is considered to face along the normal of that plane.

If the clockwise_limit of the rotation data for an axis is set to SE_POSITIVE_INFINITY and its counterclockwise_limit is set to SE_NEGATIVE_INFINITY, the aggregating <Geometry Hierarchy> instance can rotate freely about that axis. If all axis limits are set in this way, the <Geometry Hierarchy> instance rotates freely in any direction about the centre of rotation.

Primary Page in DRM Diagram:

• 7

Secondary Pages in DRM Diagram:

• 3
• 4

Example

1. Consider a <Union Of Primitive Geometry> instance containing a single textured <Polygon> instance that is rotating freely about the w axis to represent a tree. The <Union Of Primitive Geometry> instance in this example has a <Stamp Behaviour> component, with u_axis_limits and v_axis_limits set to 0.0 for both the clockwise_limit and counterclockwise_limit, and w_axis_limits set to SE_POSITIVE_INFINITY for clockwise_limit and SE_NEGATIVE_INFINITY for counterclockwise_limit. The <Stamp Behaviour> instance has an <LSR 3D Location> component specifying a location at the base of the tree, so that the w axis runs up the centre of the tree.

FAQs

Since <Stamp Behaviour> instances shall be specified in a 3D LSR SRF, why is the centre of rotation a <Location 3D> rather than an <LSR 3D Location>?

Because if and when a <Stamp Behaviour> instance's native LSR SRF is instanced into a non-LSR SRF, the <Location 3D> shall be specified so that it can be transformed into the target SRF.

Constraints

• <<Publishable Object>>
• <<Stamp Behaviour constraints>>

Composed of (two-way)

• one <Location 3D> instance¹

Component of (two-way)

• zero or more <Aggregate Geometry> instances
• zero or more <Geometry Model Instance> instances

Inherited Field Elements

Field Elements

Notes

Composed of Notes

Location_3D

Fields Notes

u_axis_limits

The u_axis_limits field specifies the angular limits around the u axis.

v_axis_limits

The v_axis_limits field specifies the angular limits around the v axis.

w_axis_limits

The w_axis_limits field specifies the angular limits around the w axis.