The SEDRIS Data Representation Model
APPENDIX A - Classes
State Related Geometry
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Class Name: State Related Geometry
Subclasses
This DRM class is concrete and has no subclasses.
Definition
A mechanism for specifying discrete states from a possibly continuous
state value. Each discrete state corresponds to a branch of the
<State Related Geometry> and is
identified by the <State Data> for
that branch; the state value itself is given by the
state_tag
of <State Related Geometry>.
Primary Page in DRM Diagram:
Secondary Pages in DRM Diagram:
This class appears on only one page of the DRM class diagram.
Example
- Consider a <Model> of a building which has four
different geometric representations, representing different damage states.
The <Model> therefore has a <
Geometry Model>, the geometry of which is organized via a
<State Related Geometry> instance with
4 branches, one for each damage state, as shown below.
Each branch of the <
State Related Geometry> has a <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 <Geometry Model Instance> to
specify a percent damage value via a <
State Control Link>.
The mismatch_behaviour of the can be exploited
to 'turn off' the if a damage value is
fed in which does not match one of the damage states. (This is
why the 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 ,
SE_STATE_MSM_BHVR_LAST would be specified.
The mismatch_behaviour would not be needed if the 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 5 states of
EAC_WIND_RESPONSE (wind speed response), where the response to
wind direction is implemented by using a <
Rotation Control Link> tied to an
EAC_WIND_DIRECTION <Variable>.
- Identifies one of alternative appearances for some
"state-applicable"
attribute.
- For a <State Related Geometry>
representing different states of an aircraft hatch for
EAC_OPENING_COVER_POSITION, one
<State Data> with
EEC_OPNCOVPOS_CLOSED and another with
EEC_OPNCOVPOS_OPEN.
- For a <State Related Geometry>
representing different damage states of a building for
EAC_GENERAL_DAMAGE, <
State Data> for [0, 25) % damage, [25, 50) % damage,
[75, 100) % damage, and [100, 100) % damage.
- For a <State Related Geometry>
representing different states of a forest for healthy vs. burned,
EAC_GENERAL_DAMAGE could be used.
FAQs
- Is <State Related Geometry>
the only way to represent multi-state objects in SEDRIS?
No. <Control Link> instances can be
used to provide a fine level of control over state by changing fields
instead of representing states as different
<Geometry> objects.
Constraints
Associated by (one-way)(inherited)
Associated with (two-way)(inherited)
Composed of (two-way)(inherited)
Composed of (two-way)
Composed of (two-way metadata)(inherited)
Component of (two-way)(inherited)
Notes
Associated with Notes
An association between a <Geometry Hierarchy> instance and a
<Feature> instance indicates that the <Geometry Hierarchy>
and the <Feature> are alternate representations of the same
environmental object.
An association between two <Geometry Hierarchy> instances
indicates that they are alternate representations of the same
environmental object.
An association from a <Hierarchy Summary Item> instance to a
<Geometry Hierarchy> indicates that the <Hierarchy Summary Item>
summarizes that <Geometry Hierarchy>.
An association from a <Reference Surface> instance to a
<Geometry Hierarchy> indicates that the <Geometry Hierarchy>
organizes the geometric objects that specify the resolution
surface of the <Reference Surface>.
Composed of Notes
In the case where multiple <Collision Volume> components are
specified for a given <Aggregate Geometry>, the union of the
volumes thus specified is used in collision detection.
Fields Notes
If this value is SE_TRUE, each 'descendant' of this aggregation -
that is, each <Geometry> object that exists in the component tree
rooted at the given <Aggregate Geometry> - shall be unique, in the
sense that it shall appear in only one 'branch' of this aggregation.
If unique_descendants is SE_FALSE, at least one <Geometry> object
appears in more than one 'branch' of the aggregation.
If this value is SE_TRUE, each 'branch' of this aggregation
strictly complies with the organizing principle for its
particular subclass. If this value is SE_FALSE, at least
one 'branch' does not strictly comply with the given
organizing principle. See the organizing principle constraint
for each specific subclass for details.
The state by which the component <Geometry Hierarchy> instances
are being differentiated, which shall be an EAC which is designated
as "state applicable".
The default state.
If a <State Control Link> is present, then this field
is its target.
Prev: State Related Features.
Next: Strobing Light Behaviour.
Up:Index.
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Last updated: October 1, 2002
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Copyright © 2002 SEDRIS™
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