Table 6.216—DRM_Property_Table_Reference_Control_Link

Property

Description

Superclass

· <DRM Control Link>

Class

· <DRM Property Table Reference Control Link>

Subclass

· None

Definition

An instance of this DRM class specifies a <DRM Expression>, the value of which determines the index_on_axis field value of the target(s).

The expression_index field is a 1-based index into the ordered aggregation of <DRM Expression>s, and is used to select the specific <DRM Expression> that defines the index_on_axis field of the <DRM Property Table Reference>.

Example(s)

· Consider an instance of a geometric model of a wind sock, which is to be rotated depending on the wind direction; that is, whenever the wind changes, the <DRM Geometry Model Instance> is rotated accordingly.

The <DRM Rotation> of the applicable <DRM LSR Transformation> controlled by a <DRM Rotation Control Link>, which is driven using values from a <DRM Property Table>. That is, the <DRM Rotation Control Link> is driven by a <DRM Predefined Function> TABLE_VALUE containing a <DRM Property Table Reference> referring to the <DRM Property Table> containing the rotation values.

The wind sock rotates around the Y axis, depending on wind speed. (That is, if the wind speed is zero, it'll hang down toward the ground, while if the wind speed is higher, it'll straighten out parallel to the ground).

The <DRM Property Table> is classified as ECC_CONTROL_VALUE, and has a <DRM Table Property Description> specified by ROTATION_ANGLE. The <DRM Property Table> specifies, for each EAC_WIND_SPEED value, the angle to which the wind sock should be rotated.

· Consider a <DRM Translation Control Link> instance that is to be driven using values from a <DRM Property Table>. The table values that are to be used are to be cycled through 8 times, with each cycle taking 10 seconds. This sequence of cycles is to be triggered from outside the transmittal.

The controlling <DRM Expression> of the <DRM Translation Control Link> is a <DRM Predefined Function> instance for TABLE_VALUE, whose argument is a <DRM Property Table Reference> instance referring to the <DRM Property Table> containing the translation values.

Note that the <DRM Table Property Description> for the control values and the <DRM Variable> instance controlling the referencing expression have the same meaning = {VARIABLE, {TRANSLATION_AMOUNT}}

The <DRM Property Table Reference Control Link> controls which value is referenced from the <DRM Property Table>, and is itself driven by the CYCLE_TIME <DRM Predefined Function>. The cycle length (10 seconds) and the number of cycles (8) are specified as arguments to the function.

The <DRM Variable> drives the <DRM Property Table Reference Control Link> through the <DRM Predefined Function>, so that it determines which value is referenced from the <DRM Property Table>. To provide the hook for this <DRM Variable> to be set from outside the transmittal, the <DRM Variable> is associated with an <DRM Interface Template> (not shown).

If this <DRM Translation Control Link> appears inside a <DRM Model>, then to set the <DRM Variable> using another variable from outside the transmittal, the data provider merely has to have the <DRM Geometry Model Instance> supply a <DRM Variable> from its own context for the value of the  <DRM Variable> of the <DRM Model>.

Inherited field elements

field_name	range	Field_Data_Type
description^1		String

Field elements

field_name	range	Field_Data_Type
expression_index^2		Integer_Unsigned

Associated to (one-way) (inherited)

· none

Associated to (one-way)

· none

Associated by (one-way) (inherited)

· none

Associated by (one-way)

· none

Associated with (two-way) (inherited)

· none

Associated with (two-way)

· none

Composed of (two-way) (inherited)

· one or more {ordered} <DRM Expression>

Composed of (two-way)

· none

Composed of (two-way metadata) (inherited)

· none

Composed of (two-way metadata)

· none

Component of (two-way) (inherited)

· none

Component of (two-way)

· one or more <DRM Property Table Reference>s

Constraints

· none

Notes

¹ A text description of what the <DRM Control Link> is for.

² For a <DRM Property Table Reference Control Link> instance, this value specifies which of the ordered <DRM Expression> components is that which controls the index_on_axis value of the affected <DRM Property Table Reference> instances.

Class diagram

<DRM Property Table Reference Control Link>