Polyhedron (polygons)


Synopsis

Set subobject values for Polyhedron (actually polygon) Cell_Sets.

 

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Cell_Set Polyhedron { /* polyhedron cell definition */
cell_nnodes = 3;
cell_ndim = 2;
cell_order = 1;
poly_flag = 1;
int poly_type = 1; /* to distinguish from Polytri */
int npolys;
int poly_nnodes[npolys]; /* number of vertices */
int poly_connect_list[]; /* node connectivity array */
int concave_flag;
ncells => cache(get_ncells_polyhedron(npolys, poly_nnodes));
node_connect_list => cache(get_connect_polyhedron(
npolys, poly_nnodes,
poly_connect_list, concave_flag));
int+virtual cell_type = 19;
string+virtual cell_name = "Polyhedron";
float+virtual node_uvw[3][3] => {{1.0,0.0,0.0}, {0.0,1.0,0.0}, {0.0,0.0,0.0}};
};

 

Description

The Polyhedron cell set type defines the members of this cell set as Polyhedron cells, which actually contain 2D polygons (the cell set is misnamed). Each polygon can have a different number of vertices. The polygons are defined in the order they appear in the poly_nnodes array. The first element of this array, call it n , specifies the number of sides for the first polygon. The first n elements of the poly_connect_list array specify the vertices of that polygon. The next element of poly_nnodes specifies the number of sides for the second polygon, and so on. The total number of polygons is set by npolys.

Subobjects

cell_nnodes = 3

How many nodes make up the cell. Cells with mid-edge nodes have more nodes.

 

cell_ndim = 2

How many spatial dimensions make up the cell.

 

cell_order = 1

cell_order = 1 means the cell has corner nodes only. cell_order = 2 means the cell has mid-edge nodes.

There is no FLD routine to retrieve this value.

poly_flag = 1

A flag that, when not 0, signals the renderer that this is an unstructured mesh representing a geometry (Polyline, Polytri, Polyhedron). The renderer can use faster algorithms to render the object.

There is no FLD routine to retrieve this value.

poly_type = 1

This value determines which type of poly object is contained in the cell set.

npolys

An integer specifying how many polygons are in the cell set.

poly_nnodes[npolys]

An integer array specifying how many vertices (or lines) are in each polygon.

poly_connect_list[]

An integer array containing indices into the node coordinate array specifying which nodes are the corners of each polygon. The first poly_nnodes[0] elements of this array specify the vertices of the first polygon; the next poly_nnodes[1] specify the corners of the next polygon, and so on.

concave_flag

An integer which specifies whether the polygons in the cell set are concave or not. (In the example above, the first and second polygons are both concave).

cell_type = 19

An integer that uniquely identifies the type of cells in this cell_set. This is one means of discovering this; cell_name is another.

 

cell_name = "Polyhedron"

A string that uniquely identifies the type of cells in this cell_set.

 

node_uvw[1][3]

A float array that defines the uvws for the nodes. The uvws are necessary when you are interpolating within a cell by calculating derivatives. The coordinates are parametric.

 

Files

v/fld.v

See also

Not applicable.