# Extrude
A set of nodes, elements or members must be selected prior to opening this dialog box, to serve as the basis of the extrusion.
The extrude operation copies a set of nodes by a specified number of increments and increment length either along a specified Axis of a specified axis set or along a specified Alignment, if any Alignments are defined. The option is given to Include Beam elements along extrusion and to Include Quad4 elements along extrusion during the extrusion process.
If the selected elements (or members) have the same local axes then selecting the ‘local’ axis option specifies the local element axis set as the axis for the extrude; otherwise, similarly, if the selected nodes have the same constraint axes then these will be the local axis directions. Note that the entity type used for local axis interpretation is independent of the type of entities being extruded. E.g. When extruding nodes, it is possible first to select the element that is to define the local axis directions, then to select the nodes that are to be extruded before opening the Extrude dialog.
# Assignment of Property and Group numbers to new elements
For extrusions that are based on a selection of elements, the copies of the selected elements at each increment are assigned the same property and group number as the original element. Otherwise the default property is assigned as it is assumed that the property numbers will have to be adjusted manually. To facilitate selection for the purpose of the assignment of property numbers, unique group numbers are assigned to the group of new longitudinal beam elements, to the group of new 2D elements and to the group of new transverse beam elements, respectively.
# Extruding a set of nodes
If the extrusion is based on a set of nodes and the Include Quad4 elements along extrusion option is selected then the nodes are ordered geometrically for the purpose of connecting nodes with Quad4 elements along the extrusion. This can lead to bizarre element generation if the nodes cannot be ordered sensibly; this can be overcome by carrying out the extrusion in several steps.
# Extruding a set of elements
If the extrusion is based on a set of elements then copies of the selected elements are included at each increment. If the Include Quad4 elements along extrusion option is selected a Quad4 element is created between each increment for each 1D element selected.
# Extruding a set of members
If the extrusion is based on a set of members then copies of the selected members are included at each increment. If the Include 2D members along extrusion option is selected a 2D member is created between each increment for each 1D member selected.
# Coincident nodes
The option is given to check for an existing node within the coincidence tolerance of the position of a required node before creating a new node.
The extrusion can be previewed before committing to the creation of nodes and elements.