Edges can be extruded to create new polygons. Edges are extruded with different behaviors depending on whether they are ‘internal’ or ‘external’ (inside the mesh, or on the perimeter boundary). The constraint methods are the same as with extruding polygons, so only issues specific to edge extrusions are shown below.
Tools are organized into tool groups. Each tool within the tool group can have its own key, but can be cycled to via a ‘tool group’ key. By default, the U key cycles the tool group, but also activates the current tool within the group when another tool is currently active.
Extrude Element
Tool
Extrude Inset
Tool
Extrude Element Tool
Extruding External Edges
A new polygon can be created by extruding, or extending out, a selected edge or edges. Edges are extruded using the same constraint methods used by polygon extrusion.
Edges are classified as either internal or external (on open boundaries).
External edges are on the boundary of an object. Internal edges are all other edges, meaning a polygon sits on either side of the edge. Internal edges are generally extruded by ‘breaking’ the geometry on either side of the original edge. This is explained on the next page.
New edge extruded along the Z axis.
Extruding Internal Edges
A new polygon can be created by extruding, or extending out, a selected edge or edges. For internal edges, a new polygon is placed on either side of the original edge. This is a mechanism called ‘breaking edges’ (discussed on the next page).
New edge extruded along the Z axis.
Extrude Inset Tool
Extrude Insetting edges
When used with edges, the Extrude Inset tool allows for the interactive ‘breaking’ of selected edges without moving the original edge. A new set of polygons are created around the selected edges. This can also be done numerically by setting the Nudge Amount in the Move tool.
Edge Inset using either nudging
or mouse dragging.
or mouse dragging.
Break Edges Option
and Nudging
and Nudging
Break Edges On
The effect this option has can be seen in the two illustrations below. The original edge is ‘broken’ and replaced by three dimensional geometry. The size of this break is determined by the Nudge Amount set in the
Move Tool (double click the Move tool).
Move Tool (double click the Move tool).
If the break edges option is enabled, Design3D will automatically use the break edges function for internal edges and non-broken edges for external edges (open boundary edges). This option gives the user the ability to manually determine its usage.
Edge extrusion with break edges on. Nudge amount set to 0.5 inches.
Edge extrusion with break edges on. Nudge amount set to 0.15 inches.
Double click Move tool to set value.
Break Edges Off
‘Break Edges’ can be turned off allowing for a unique geometric configuration. This three polygon to edge configuration generally won’t be used for final geometry but can be useful for some construction purposes. See example below.
An Unusual Configuration:
Three Polygons Sharing a Single Edge
Three Polygons Sharing a Single Edge
This is a geometric configuration possible with the break edges option disabled and an internal edge extruded. This is an unusual configuration that isn’t usually something that should remain for final geometry, but can be useful for modeling purposes.
