by Dennis Collin
When working in AutoCAD, certain blocks or External Reference file drawings import and display at the wrong size. This seems to be a common problem, especially when users are self-taught and it is usually related to how AutoCAD’s drawing units are set with the originator.
To investigate, open the problem file and establish that the drawing has been drawn at 1:1 scale. Measure a known object and check that it shows the expected dimension. If it doesn’t read as the same this is most likely the problem as the drawing is not drawn to real size.
If the measurements tally, access the units command and check and set the unit type to the correct system. Unitless unit type should be rarely used. Typically in the UK for architecture, manufacturing and engineering the system unit should be millimetres. For Civil engineering and larger scale schemes the unit type is often metres.
A similar approach should be made when defining blocks, where the unit type should reflect on how the element is drawn. Again, for most disciplines in the UK this is usually millimetres.