Table 6

Table 6.105—DRM_Finite_Element_Mesh

Property

Description

Superclass

· <DRM Primitive Geometry>

Class

· <DRM Finite Element Mesh>

Subclass

· none

Definition

This class describes a tessellation of a surface into mesh faces. Additional data may be associated with each vertex or mesh face. The surface is represented by a specialized set of <DRM Data Table>s.

More specifically, a <DRM Finite Element Mesh> instance is comprised of:

a. an ordered list of <DRM Vertex> instance components that associates an index number to each <DRM Vertex> instance;

b. a <DRM Mesh Face Table> instance containing the face elements and optionally, the topology of face elements;

c. optionally, other <DRM Property Table> instances providing additional data.

Data associated with <DRM Vertex> instances shall be provided in a <DRM Property Table> instance with the tag of the <DRM Classification Data> instance set to MESH_NODE_PROPERTY_SET and having the first <DRM Axis> component of DRM class <DRM Regular Axis> as follows:

Field	Value
axis_type	{TYPE_INDEX, (MESH_VERTEX}} is an index into the ordered <DRM Vertex> list, identifying the <DRM Vertex> instance for which data is being provided
axis_value_count	total number of <DRM Vertex> instances
value_unit	UNITLESS
value_scale	UNI
first_value	1
spacing	1

Data associated with mesh faces shall be provided in a <DRM Property Table> instance with the tag of the <DRM Classification Data> instance set to MESH_FACE_PROPERTY_SET and having the first <DRM Axis> component of DRM class <DRM Regular Axis> as follows:

Field	Value
axis_type	{TYPE_INDEX, {MESH_FACE}} is the index from the <DRM Mesh Face Table>.
axis_value_count	total number of mesh faces in the table
value_unit	UNITLESS
value_scale	UNI
first_value	1
Spacing	1

Example(s)

· In support of a rain run-off computational model, a ground surface area is triangulated. At each triangle vertex, the gradient, porosity, flow resistance, water capacity, and rain rate are measured.

This data set is represented in a <DRM Finite Element Mesh> instance by:

d. an ordered list of <DRM Vertex> instances (one for each triangle vertex);

e. a <DRM Mesh Face Table> to define the triangles;

f. a MESH_FACE_PROPERTY_SET <DRM Property Table> for the gradient data; and

g. a MESH_NODE_PROPERTY_SET <DRM Property Table> for the remaining properties.

An example of such a finite element mesh might be shown as in the following figure: