Class Name: Light Rendering Properties Control Link

Superclass - <Control Link>

Subclasses

Definition

An instance of this DRM class is a specialized <Control Link> instance providing the connection between one or more <Light Rendering Properties> instances and the <Expression> instances that are used to determine whether the target <Light Rendering Properties> instances are active and / or their candela_value field values.

Primary Page in DRM Diagram:

• 17

Secondary Pages in DRM Diagram:

• 21

Example

1. Consider a flight simulator database containing an area of terrain representing a city as seen from the air. Some of the <Polygon> instances of this terrain representation have <Light Rendering Properties> with <Twinkling Light Behaviour>, representing city lights. These <Light Rendering Properties> share a <Light Rendering Properties Control Link> that turns them on and off depending on the time of day (on at dusk, off at dawn).

2. Consider a runway, bordered on either side by a <Line> representing the runway lights. Each <Line> has a <Light Rendering Properties> with <Strobing Light Behaviour>, and a <Light Rendering Properties Control Link> that turns the lights on and off depending on the time of day (on at dusk, off at dawn).

FAQs

What does a <Light Rendering Properties Control Link> control?

A <Light Rendering Properties Control Link> controls whether the associated <Light Rendering Properties> are on or off, and the candela_value of the <Light Rendering Properties>.

Can a <Light Rendering Properties Control Link> be used to change the <Light Rendering Behaviour> of the <Light Rendering Properties>?

No. The links to the <Light Rendering Behaviour> instances are associations within the transmittal, and associations cannot be changed dynamically.

Constraints

• <<Publishable Object>>

Composed of (two-way) (inherited)

• one or more {ordered} <Expression> instances

Component of (two-way)

• one or more <Light Rendering Properties> instances

Inherited Field Elements

Field Elements

Notes

Fields Notes

description

 The description field specifies a text description of the given
 <Control Link> instance's purpose.

active_expr_index

 The active_expr_index field specifies which component <Expression>,
 if any, specifies the active_light_value of the target
 <Light Rendering Properties> instances. If active_expr_index is
 zero (0), the active_light_value field values of the target
 instances are not controlled; otherwise, the value is a 1-based
 index into the ordered aggregation of <Expression> instances.

candela_value_expr_index

 The candela_value_expr_index field specifies which component
 <Expression>, if any, specifies
 the candela_value of the target <Light Rendering Properties>
 instances. If candela_value_expr_index is zero (0), the candela_value
 field values of the target instances are not controlled; otherwise,
 the value is a 1-based index into the ordered aggregation of
 <Expression> instances.

lower_candela_value_expr_index

 The lower_candela_value_expr_index field specifies which
 component <Expression>, if any, specifies
 the lower limit of the candela_value of the target
 <Light Rendering Properties> instances. If lower_candela_value_expr_index
 is zero (0), no lower limit is specified; otherwise, the
 value is a 1-based index into the ordered aggregation of
 <Expression> instances. Note that if candela_value_expr_index
 is zero, the candela_value field values of the target instances
 are not controlled, so this value would also be zero.

upper_candela_value_expr_index

 The upper_candela_value_expr_index field specifies which component
 <Expression>, if any, specifies the upper limit of the candela_value
 of the target <Light Rendering Properties> instances. If
 upper_candela_value_expr_index is zero (0), no upper limit is
 specified; otherwise, the value is a 1-based index into the
 ordered aggregation of <Expression> instances.

 Note that if candela_value_expr_index is zero, the
 candela_value field values of the target instances are not
 controlled, so this value would also be zero.