| Enumerant | Definition | Value |
|---|
| SE_GTL_ZERO |
Topology level 0.
The following DRM objects, and relationships among those
DRM objects, are required to exist:
DRM objects:
<Geometry Node> - one or more instances.
<Geometry Edge> - required if any <Geometry Face> instances
exist
Relationships:
<Geometry Node> <-> <Geometry Edge> association -
- required for each <Geometry Edge> instance that is connected
to a given <Geometry Node> instance
- required for each of the two <Geometry Node> instances
(starting node and ending node) that bound each
<Geometry Edge> instance
Constraints:
No additional constraints are required.
Other types of geometry topology objects and relationships MAY
exist at level 0, but are not required.
The requirements of level 1 must NOT be met (that is, there must be
at least one pair of collocated <Geometry Node> instances).
|
1 |
| SE_GTL_ONE |
Topology level 1.
DRM objects and Relationships:
No additional types of DRM objects or relationships are required.
Constraints:
The <Point Geometry> instances corresponding to each <Geometry Node>
shall have <Location> instances with unique coordinates (that is,
no two <Geometry Node> instances may be collocated).
The requirements of level 2 must NOT be met; that is, at least
one pair of intersecting <Geometry Edge> instances must exist.
|
2 |
| SE_GTL_TWO |
Topology level 2.
Objects and Relationships:
No additional types of objects or relationships are required.
Constraints:
The <Linear Geometry> instances corresponding to <Geometry Edge>
instances may not intersect or overlap one another, except where
they meet at a <Point Geometry> instance corresponding to a common
<Geometry Node> instance.
The requirements of level 3 must NOT be met.
|
3 |
| SE_GTL_THREE |
Topology level 3.
The following objects and relationships are required to exist, in
addition to the requirements of topology level 2:
Objects:
<Geometry Face> - one or more instances
Relationships:
<Geometry Node> <-> <Geometry Face> association - required for
each <Geometry Node> instance located in the interior of a
<Geometry Face> instance
<Geometry Edge> -> <Geometry Face> association - required for
each of the <Geometry Face> instances that each <Geometry Edge>
instance bounds
<Geometry Face Ring> -> <Geometry Edge> association - required
for each of the <Geometry Edge> instances that each
<Geometry Face> instance is bounded by.
Constraints:
The <Surface Geometry> instances corresponding to <Geometry Face>
instances may not intersect or overlap one another, except where
they meet at a <Linear Geometry> instance corresponding to a
common <Geometry Edge> instance.
Each <Geometry Edge> instance must bound exactly two
<Geometry Face> instances.
|
4 |
| SE_GTL_FOUR |
Topology level 4.
Objects and Relationships:
No additional types of objects or relationships are required.
Constraints:
Each <Geometry Edge> instance may bound zero or more
<Geometry Face> instances. (This overrides the level 3
constraint.)
At least one <Geometry Edge> instance must bound more than two
<Geometry Face> instances.
|
5 |
| SE_GTL_FIVE |
Topology level 5.
The following objects and relationships are required to exist, in
addition to the requirements of topology level 4:
Objects:
<Geometry Volume> - one or more instances
Relationships:
<Geometry Node> <-> <Geometry Volume> association - required for
each <Geometry Node> instance located in the interior of a
<Geometry Volume> instance.
<Geometry Edge> <-> <Geometry Volume> association - required for
each <Geometry Edge> instance completely located in the interior
of a <Geometry Volume> instance.
<Geometry Face> -> <Geometry Volume> association - required for
each of the <Geometry Volume> instances that each <Geometry Face>
instance bounds.
<Geometry Volume Shell> -> <Geometry Face> association - required
for each of the <Geometry Face> instances that each
<Geometry Volume> instance is bounded by.
Constraints:
The <Volume Geometry> instances corresponding to <Geometry Volume>
instances may not intersect or overlap one another, except where
they meet at a <Surface Geometry> instance corresponding to a
common <Geometry Face> instance.
|
6 |