Yes, ANNOAUTOSCALE is an AutoCAD setting, but hey, Civil 3D is an AutoCAD-based product so I’m thinking it’s fair game.  This variable can be a good thing, but it has functionality that could be described as highly undesirable.  Read on for more…

What is ANNOAUTOSCALE?  Well, you need to be familiar with AutoCAD’s annotative objects to really appreciate this post.  You already know how Civil 3D’s labels adjust their size relative to the viewport scale.  You need to do absolutely nothing for this to work.  Great!

AutoCAD itself has its own version of this.  “Annotative” objects, such as MTEXT, DIMENSIONS, BLOCKS etc. can be made “Annotative”.  This automatic scaling doesn’t just happen though, like in Civil 3D.  For each different viewport scale you will be using you need to add the appropriate scales to those annotative objects.  This can be a little frustrating, but once you get into the workflow it’s a really cool feature.

Luckily, AutoCAD has a setting known as ANNOAUTOSCALE.  As you change scales in model space or change viewport scales in paper space, those scales get added automatically to your annotative objects.  Great again!

This variable even works within XREF’s.  Say you have some annotative objects in a file that you’ve XREF’d into your plan/profile drawing.  The blue and red text below are XREF’d into the plan/profile drawing.

As you add scales to the plan/profile drawing, those scales will be automatically added to those XREF files.  Fantastic!

Here’s the rub though.  Maybe someone has those XREF files open.  Those scales cannot be added to those files because they are open.  You see, when you add scales and want those scales to be added automatically, AutoCAD essentially opens the XREF’s and adds the scales, saves, and then closes them.  It’ can’t access the files if they are open.

Here’s another problem; and this is the one this post is really meant to identify.  Maybe your company has a mandate that even though you’re using AutoCAD 2010, you must save your files to 2007 format.  Of course, AutoCAD can be made to do this automatically.  Remember what I mentioned in the last paragraph; as you add scales, AutoCAD opens the XREF’s, makes the changes and then saves.  Well, guess what, those XREF’s are saved in 2010 format! 

This is a problem since the company states that all files shall be in 2007 format.  Through no fault of your own there are 2010 format files floating around simply because ANNOAUTOSCALE is on.

This may not be a make or break problem for you; not many companies automatically save file to previous versions, but I know some that do and I know that this is a problem for them.

Hopefully you can put this post to some use.

Matt Kolberg