Hi all,
after the update of Revit, diameter symbols are not showing. In mechanical setup I can clearly see the diameter sign, but when I use it inside drawings I get some strange symbol. Please see pictures for further details.
Best regards, Branimir.
Hi @Anonymous,
Hope you are well! 
You have two options here as the general cause for this is due to the Windows True Type Font (.ttf) set installed on you Workstation and whether the Text being used in your Duct Tag ties up with your supported .ttf sets.
For example, not all .ttf in windows support all of the SI Symbols. So, if your Duct Tag Label Text used is an unsupported font of SI Symbols, then weird things would happen. IF you are using "Arial", then it will support pretty much every SI Symbol. Your .ttf on your machine might need to be re-installed. Your IT department will be able to assist with this. There might be a bug with your current .ttf installation. You can use your Windows Character Map and scroll through the different Fonts to see which Fonts support SI Symbols, mainly the Diameter Symbol in this case.
Let's assume everything is ok with your .ttf and your Duct Tag text being used is set to Arial (double check this), then you would simply be able to copy the Diameter Symbol from the Character Map and paste it into your Mechanical Settings Round Duct Size as a Prefix or Suffix. It should work.
Let's assume you're still having problems, then you have the option to copy the Diameter Symbol into your Duct Tag Label as a Prefix or Suffix which is aligned with your Duct Tag Label Text being used. (You'll then just need to remove the Round Duct Size Prefix and Suffix under your Mechanical Settings as show above, otherwise you'll be left with a symbol duplication).
You'll then have two Duct Tag Family Types to choose from, the Round and Rectangular Duct Size Tags as you would not want the Diameter Prefix to show up when tagging rectangular ductwork as displayed below.
I attached the sample project which has the duct tag in it which I used in the sample above for you to play around with.
(I used Revit 2018 in the samples above)...
I hope this helps!
Hi again!
I tried everything and this diameter symbol isn't working. We usually use Tahoma font, but I also tried Arial, but no luck with both of them. It is interesting that it seems that all other symbols are working except that diameter sign. I also attached sample project where diameter sign is shown as r (see picture).
I am interested do you see the same on attached test file, or when you open the file you see sign as on picture?!
Best regards, Branimir.
Hi @Anonymous,
Ok, so I opened your file and the symbol displayed as it should where I didn't need to change anything. You mentioned that other special characters are working the way in which they should. Then your fonts might have gone corrupted. I've seen this happen quite a bit in the past, mainly in AutoCAD and the same thing happened. Diameter was the only faulty symbol.
Have you tried restore the default font settings on your system? Or reinstalling the Arial font?
Here are some instructions to help you do so:
Here is an additional LINK which might be useful. You can download default Windows Fonts from HERE.
I hope this helps!
The issue with special charecters still exists on various machnies, Revit and Windows versions.
