A simple example is provided in 4.16.6.3 <DRM Property Table Reference Control Link> of ISO/IEC 18023-1.
Consider an instance of a geometric model of a wind sock that is to be rotated depending on the wind direction. Whenever the wind changes, the <Geometry Model Instance> instance is rotated accordingly.
The <Rotation> component of the applicable <LSR Transformation> instance is controlled by a <Rotation Control Link> component, which is driven using values from a <Property Table> instance as depicted in Figure 6.44. The <Rotation Control Link> component is driven by a <Predefined Function> component with function = SE_PREDEFFN_TABLE_VALUE, which in turn has a <Property Table Reference> component associated to the <Property Table> instance containing the rotation values.
The wind sock rotates around the V axis, depending on wind speed. If the wind speed is zero, it hangs down toward the ground, while if the wind speed is higher, it straightens out parallel to the ground.
The <Property Table> instance is classified as ECC_CONTROL_VALUE, and has a <Table Property Description> component specified by SE_VARCOD_ROTATION_ANGLE. The <Property Table> instance specifies, for each EAC_WIND_SPEED value, the angle to which the wind sock should be rotated as depicted in Figure 6.45.
Consider a <Translation Control Link> instance that is driven using values from a <Property Table> instance. The table values that are to be used are cycled through eight times, with each cycle taking ten seconds. This sequence of cycles is triggered from outside the transmittal as depicted in Figure 6.46.
The controlling <Expression> component of the <Translation Control Link> instance is a <Predefined Function> component with function = SE_PREDEFFN_TABLE_VALUE, whose argument is a <Property Table Reference> component associated to the <Property Table> instance containing the translation values as depicted in Figure 6.47.
The <Table Property Description> instance for the control values and the <Variable> instance controlling the referencing expression have the same meaning = {SE_ELEMTYPCOD_VARIABLE, {SE_VARCOD_TRANSLATION_AMOUNT}}
The <Property Table Reference Control Link> instance controls which value is referenced from the <Property Table> instance and is itself driven by the <Predefined Function> component with function = SE_PREDEFFN_CYCLE_TIME. The cycle length (ten seconds) and the number of cycles (eight) are specified as arguments to the function.
The <Variable> instance drives the <Property Table Reference Control Link> instance through the <Predefined Function> instance so that it determines which value is referenced from the <Property Table> instance. To provide the hook for this <Variable> instance to be set from outside the transmittal, the <Variable> instance is associated with an <Interface Template> instance (not shown).
If this <Translation Control Link> instance appears within the component tree of a <Model> instance, in order to set the <Variable> instance using another variable from outside the transmittal, the data provider specifies that the <Geometry Model Instance> instance is to supply a <Variable> component from its own context to provide the value of the <Variable> instance within the component tree of the <Model> instance.