Class

• <DRM State Related Geometry>

Superclass

• <DRM Aggregate Geometry>

Subclass

• None.

Definition

A mechanism for specifying discrete states from a possibly continuous state value. Each discrete state corresponds to a branch of the <DRM State Related Geometry> and is identified by the <DRM State Data> for that branch; the state value itself is given by the state_tag of <DRM State Related Geometry>.

Class diagram

Figure 6.308 — DRM_State_Related_Geometry

Constraints

• Colour Mapping restrictions
• Distinct geometric centre
• Distinct link objects
• Image Mapping Functions and Texture Coordinates
• No attribute conflicts
• Non crossing aggregations
• Non crossing associations
• Non cyclic aggregations
• Precedence of Property Set Index
• Publishable Object
• State related organizing principle

Example(s)

• Consider a <DRM Model> of a building which has four different geometric representations, representing different damage states. The <DRM Model> therefore has a <DRM Geometry Model>, the geometry of which is organized via a <DRM State Related Geometry> instance with 4 branches, one for each damage state, as shown below.

  

  Figure 6.309 — <DRM State Related Geometry> example

  Each branch of the <DRM State Related Geometry> has a <DRM State Data> indicating the range of percent damage that the branch represents. The range values in the diagram therefore specify explicitly the “bins” in which the states fall.

• A slightly different design for example 1, modified to allow each <DRM Geometry Model Instance> to specify a percent damage value via a <DRM State Control Link>.

  • Add a <DRM State Control Link> component to the <DRM State Related Geometry>, with mismatch_behaviour = NONE and a <DRM Variable> V as its controlling <DRM Expression>, where V's meaning is EAC_GENERAL_DAMAGE_FRACTION.

  • Associate V to the <DRM Interface Template> component of the <DRM Model>. If the <DRM Model> has no <DRM Interface Template>, create one.

  The mismatch_behaviour of the <DRM State Control Link> can be exploited to 'turn off' the <DRM Geometry Model Instance> if a damage value is fed in which does not match one of the damage states. (This is why the <DRM Model> doesn't require a 'totally destroyed' state for 100% damage.)

  If the data provider instead wanted to keep a state transition from happening until the state value matches a <DRM State Data>, LAST would be specified.

  The mismatch_behaviour would not be needed if the <DRM Variable> only took on valid values (0,0, 0,5, 0,75, or 1,0), but this scheme does not force state values to be discrete.

• A wind sock model designed to support a landing site has state behaviour to allow it to respond to wind speed and wind direction. The wind sock is modeled with five states of EAC_WIND_RESPONSE, where the response to wind direction is implemented by using a <DRM Rotation Control Link> tied to an EAC_WIND_DIRECTION <DRM Variable>.

  

  Figure 6.310 — <DRM State Related Geometry> example

• Identifies one of alternative appearances for some “state-applicable” attribute.

  1. For a <DRM State Related Geometry> representing different states of an aircraft hatch for EAC_OPENING_COVER_POSITION, one <DRM State Data> with EEC_OPNCOVPOS_CLOSED and another with EEC_OPNCOVPOS_OPEN.

  2. For a <DRM State Related Geometry> representing different damage states of a building for EAC_GENERAL_DAMAGE, <DRM State Data> for [0, 25) % damage, [25, 50) % damage, [75, 100) % damage, and [100, 100) % damage.

  3. For a <DRM State Related Geometry> representing different states of a forest for healthy vs. burned, EAC_GENERAL_DAMAGE could be used.