by Dennis Collin
Whilst Autodesk do have products for the modelling of duct and pipe elements like CADMEP and Revit MEP, there are still projects worked using the classic AutoCAD/LT platform which only require 2D drawings.
Fig 1. The Dline command provides useful options to draw pipes or ductwork.
For AutoCAD LT users there is an often-forgotten command called Dline, or double line. This command by default can only be accessed via the command line, by typing in Dline. However, once active it allows the user to draw a double line, with a specified width, and provides options for trimming behaviours at intersections along with the application of a cap at the beginning at the end of segments. The Dline command just creates basic line elements, however the Lisp routine working in the background provides sensible options to reduce the user’s effort in creating linework for building services.
Fig 2. Dline is a useful addition to AutoCAD LT’s drawing tools!
The elements will default to the current layer but if desired, elements can be selected later and altered using default methods. If creating another Dline later, and the user references an existing Dline element the geometry can be set to trim correctly, saving time and effort.
Fig 3. By snapping a ‘Dline’ to existing geometry joins can be applied!
The Dline function has been in AutoCAD LT for many years. However, it is not available in full out-of-the-box, AutoCAD. AutoCAD, however, has multi-lines elements, but multi-lines are not flexible enough in operation to be of benefit to users. However, by accessing this Lisp routine on the Autodesk forum full AutoCAD users can have Dline functionality as well!
For a useful application of multi-lines in AutoCAD click here:
Lisp and programming can greatly enhance AutoCAD and now LT’s functionality, for more information on some useful routines check out a post on some other useful functions!