SMS:Build Polygons

While most feature objects can be constructed with tools in the Tool Palette, polygons are constructed with the Build Polygons feature object command. Since polygons are defined by arcs, the first step in constructing a polygon is to create the arcs forming the boundary of the polygon. All closed loops will be formed into polygons.

Before defining material zones or creating meshes from a coverage, the Build Polygons command must be used.

Once polygons exist in the project, the Select Polygon tool becomes active. If a polygon cannot be selected with the Select Polygon tool, check to see if the arcs in the polygon are making a closed loop by removing any gaps, then use the Build Polygons command again.

Generally, nodes and vertices can be moved on a polygon to reshape it without causing the polygon to disappear. Deleting an arc in the polygon so that it no longer makes a closed loop, will cause polygon to be removed and the Build Polygons command will need to be used again if the closed loop is reformed. If creating an additional closed loop after using the Build Polygons command, such as creating a new arc to split an existing polygon, the command must be used again to create the new polygon.

Polygon Attributes

The Polygon Attributes dialog is used to set the attributes for feature polygons. Attributes that can be specified for each polygon include:

• Polygon Type – The polygon type can be set to either Land or Ocean.

For models that generate meshes, there are certain polygon attributes that need to be set before the mesh can be created. For more information, see 2D Mesh Polygon Properties.

Related Topics

• Feature Objects Menu