AutoCAD Tip : Making Blocks Annotative for building services drawings

by Dennis Collin

When producing drawings of building services there is frequently a need to deliver drawings at different scales. Electrical symbols are especially a challenge as the element they are representing are often small in comparison to the building, but it is essential that their location and function can be clearly identified on a services plan.

In the past users would scale symbols up, but that approach can cause consistency issues across different projects and drawings. The best practice way of achieving this is to make use of Annotative annotation which was introduced way back in AutoCAD 2008! The annotative scale feature can also be used to control text, dimension, multi-leader and linetype display as well.

My colleagues and I have written several other posts and white papers on these topics:

https://www.cadlinecommunity.co.uk/hc/en-us/articles/360001921997-AutoCAD-Controlling-the-appearance-of-linetypes-in-drawings

https://www.cadlinecommunity.co.uk/hc/en-us/articles/201828891-AutoCAD-2013-Annotative-Scaling-Dimensions

https://www.cadlinecommunity.co.uk/hc/en-us/articles/360010861017-AutoCAD-2021-An-Overview-of-Creating-Annotative-Objects

When setting up blocks for annotative behaviour, it is important that they are drawn at the actual plotted size. For example, a socket symbol drawn as a filled semi-circle would be typically drawn at a size of between 2 to 3 millimetres. Define the block as normal, and set the base point, select the objects that will form the symbol and ensure that annotative behaviour is set.

Fig. Tick highlighted box to make blocks smarter!

Save the block to a library, and access via a suitable environment such as AutoCAD Tool Palettes or the Designcentre interface. When working in AutoCAD set the Annotation scale to whatever the intended plot scale is going to be. (Typically, 1:50 or 1:100)

Fig. Setting the Annotative (Plot) Scale

Once the annotative behaviour is enabled, changing the scale will automatically resize the symbols (and other annotation) to suit. This will ensure that when producing paper or PDF plots, the symbols will be large enough to see and read on the final issued document.

The example images below show several sockets and switches which change size as the annotation or plot scale is altered.

Fig. Electrical Symbols scaled on 1:100 drawing

Fig. Electrical Symbols scaled on 1:50 drawing

Fig. Same drawing place on a sheet sized at 1:50 and 1:25 scales, note the consistent electrical symbol sizing in both views

Annotative or smart annotation, blocks, dimensions, symbol libraries and templates are just some of the topics that are covered on an AutoCAD Intermediate course. For more details on both scheduled and custom AutoCAD courses please visit https://training.cadline.co.uk/ or talk to one of the team on 01784 419922 or via the site’s live chat facility.