By Dennis Collin
A common problem when working with drawings are users who override dimension values with false values i.e. a dimension that measures 950 millimetres for example has its measurement value overridden with a manual text string of a different value. Best practice dictates that if a measurement needs to be altered, the drawing should be modified and dimensions adjusted to suit the new arrangement or replaced as appropriate. However, in either case the dimension element should be associative with the element it is referring to.
A component size of 900mm should read 900 millimetres on the dimension annotation. Exploding dimensions or manually editing a dimension to read an alternate measurement should be a big no-no to any good AutoCAD user.
Whilst this may sound great in theory, the reality is that overridden dimensions happen way too often and for a CAD manager, or anyone tasked with checking or issuing drawings, dimensions reading wrong values, or this ‘disconnect’ with the actual printed drawings and measurements is a big problem for any discipline.
Fortunately help is at hand via the application of a simple AutoLISP routine that locates all the overridden dimensions, puts them on a separate layer and highlights them a different colour for review. Even better news, this routine will work with AutoCAD LT 2024 which now supports Lisp (albeit in a more limited capacity).
For any routines for both AutoCAD platforms, it is recommended to have a shared resource folder that all users can access. The folder can be set as a trusted location and the routine can be added to a startup suite of useful additional utilities via the APPLOAD (Application Load) function.
Please find some links about the benefits of AutoLISP, and other external routines and using the Appload command on other posts here:
As with any external applications, care should be taken when using routines from external sources. Always test any function on a safe testbed file before using on a working drawing file.
If there are any doubts about a routine, you can always contact a member of the Cadline team, where there is a helpdesk for technical queries or information on training for any Autodesk product, including AutoCAD.
A selection of the courses we offer can be found on https://training.cadline.co.uk/