By Dennis Collin
AutoCAD has many line entities as part of its command toolset. The most used entities are lines and polylines. Line elements comprise of a simple vector kind of element with a starting point, a vector, and an end point. Whilst additional lines can be snapped to them to form more complex shapes in a drawing each line segment remains a separate entity. Lines are very useful in the creation of drawings where each line segment can be placed onto a different layer and assigned different colour, linetype and line weight properties.
For some drawings however a more complex line is required, which is where a polyline can be used. Unlike lines a polyline’s segments are continuous and are used for the creation of hatch pattern fills and the measurement of areas, perimeter lines etc.
Converting Polylines to Lines is easy, it is just a case of using the Explode command. However, commands to convert lines back to polylines, can be a bit harder to locate.
For many years the Edit Polyline command has been used to ‘weld’ line segments together to form a polyline boundary. Although this command works well, the command does require some intermediate clicks to complete the task. It is the proverbial ‘sledgehammer to crack a nut’ command. Make no mistake the Edit Polyline (or PEDIT) command is a vital tool in the preparation of polylines to use in 3D Solid modelling as path or profile entities, or for editing shapes before being used to determine areas or to control hatch pattern entities. However, since AutoCAD 2012 there is a much easier and quicker way to convert lines to polylines and to simplify overlapping lines producing much more efficient and useful drawings, the Join command!
The Join command (Shortcut: J) can be accessed via the Modify draw of AutoCAD’s Ribbon menu. Click the command and then use a suitable selection method to choose the elements to connect. Users can check if the command has worked as the entire shape should highlight when selecting a line segment (See Fig 2.) The Join command can also be used to join separate Polyline entities together as well as Line segments to existing Polylines. It can also be used to convert arc elements to closed circle shapes by accessing the Close option via the command line or context menu.
Whatever your discipline, it is beneficial to have a good understanding of all AutoCAD’s commands. These are covered on many of Cadline’s AutoCAD training courses. We provide training for all levels from Essentials to Advanced, including update training and bespoke workshops, in small groups or 1-2-1 sessions. Information on our training services can be found at https://training.cadline.co.uk/ where one of the training team will be happy to help.