By Dennis Collin
AutoCAD is a very versatile drawing tool and is very tolerant in letting users do anything in a drawing. Some may argue that it is too tolerant, in that AutoCAD will happily permit users to explode dimensions or override a dimension string as text, rather than relate to the actual measurement an element has been drawn to.
When in receipt of drawings, it is desirable to be able to identify overridden or exploded elements and if necessary, take appropriate action to ensure that the annotations show the correct information. Such non-standard dimensioning entities can be set back to standard associative dims.
Using the Quick Select command (which is also present in AutoCAD LT), criteria can be set to select elements from the entire drawing. Right Click on screen and choose Quick Select (Or type Qselect on the command prompt).
Within the dialogue, select the object type "Dimension", the Property "Text override", the Operator "Wildcard Match" and as the Value enter the string (without the quotation marks) " ?* " , this wildcard string will select elements which have at least one character'.
Overridden dimensions will be highlighted, these could be changed to a inspection layer or colour for further inspection. Any dimensions that are not selected either read correctly or have been exploded. This can be verified by running Qselect again and select all dimensions in a drawing, exploded elements which look like dimensions won’t be selected as they will just be line and text entities. If selected the exploded dimensions are ‘fragile’ and show with many control points with the text having no relationship with the annotation reference lines.
If dimensions have been exploded there is no easy way to repair them. The offending elements need to be deleted and recreated using AutoCAD’s dimensioning commands. If, however, they have just been overridden, the Express Tool DIMREASSOC will set the dimension string text back to its proper value. I will discuss this process in more detail in a future post.