A line segment is a line between a starting point or vertex and endpoint or vertex in 2D and 3D. In 2D, add a Line Segment node () by right-clicking the Geometry node and select it from the context menu in 2D or from the More Primitives submenu in 3D., In the Geometry ribbon, you can choose Line Segment from the Primitives menu in 2D and the More Primitives menu in 3D.

Define the starting point for the line segment. From the Specify list, choose Vertex (the default) to specify a start vertex by selecting a vertex from the geometry or using an applicable selection in the Start vertex list. Click the Active button to toggle between turning ON and OFF the start vertex selection. Alternatively, select Coordinates to specify the x, y, and (3D only) z coordinates for the starting point.

Define the endpoint for the line segment. From the Specify list, choose Vertex (the default) to specify an end vertex by selecting a vertex from the geometry or using an applicable selection in the End vertex list. Click the Active button to toggle between turning ON and OFF the end vertex selection. Alternatively, select Coordinates to specify the x, y, and (3D only) z coordinates for the endpoint.

The coordinate system in which the coordinates above are interpreted (in 3D only, and if at least one of the Specify lists is set to Coordinates). From the Work plane list, select xy-plane (the default, for a standard global Cartesian coordinate system) or select any work plane defined above this node in the geometry sequence. If you choose a work plane, the work plane and its coordinate system appear in the Graphics window, using an extra coordinate triad with the directions xw, yw, and zw (which are then used to specify the line’s position).

Select the Resulting objects selection check box to create predefined selections (for all levels — objects, domains, and boundaries — that are applicable) in subsequent nodes in the geometry sequence. To also make all or one of the types of resulting entities (domains and boundaries) that the interval consists of available as selections in all applicable selection lists (in physics and materials settings, for example), choose an option from the Show in physics (Show in instances if in a geometry part) list: All levels, Boundary selection (2D or Edge selection (3D), or Point selection. The default is Boundary selection (2D) or Edge selection (3D). These selections do not appear as separate selection nodes in the model tree. Select Off to not make any selection available outside of the geometry sequence. From the Color list, choose a color for highlighting the resulting objects selection. See Selection Colors.

If you want to make the resulting entities contribute to a cumulative selection, select a cumulative selection from the Contribute to list (the default, None, gives no contribution), or click the New button to create a new cumulative selection (see Cumulative Selections).