Welcome to Revit Dimensions: More Than Meets the Eye, Part 2. (If you missed Part 1, click here to read it.) When we left off last time, I had just shown you how to display “equality text,” used to indicate equal spacing of items.
But of course, that isn’t your only option for equality text. If you select the dimension and head over to the Properties Palette, you’ll see Equality Display under Other. Your three choices there are Value, Equality Text, and Equality Formula.
Equality Text is the default, and it replaces each instance of the dimension value with text. Value shows the actual value of each segment, and Equality Formula—if you don’t change anything—displays the total length of the string.
We’re still not done with options, though. Equality Formula implies that you can do math with your dimension string—and you can. To see how, we’ll go into the dimension’s Type Properties.
For today, we’ll focus on the Other section. (Graphics and Text could each fill several posts on their own.) In Equality Text, you can enter the characters that appear when you choose Equality Text for an individual dimension string.
Equality Formula is where you get to have some fun. A common way of showing equal spaces is to use text like 4 SP @ 5’-0” = 20’-0”—and with Revit, you don’t have to type in any of that by hand. Instead, launch the Equality Formula dialog. Here’s what it would look like to create that string:
Now for the explanation. The only parameter selected to begin with was Total Length, which resulted in the image shown earlier. I added two parameters to the label—Number of Segments and Length of Segment—and rearranged them in the correct order. Then I added a Prefix and Suffix to the Length of Segment parameter. (Note that they could have been added instead to the Number of Segments or Total Length—it’s up to you. Also, pay attention to spaces—you may need to add them to properly separate the parameters.)
Click Okay, and…ta-da!
There’s one last tweak you could make to streamline the display even more. Remember the last setting in the Other section of the Type Properties? It was Equality Witness Display, and it controls the interior witness lines in a dimension string.
Your options are Tick and Line, Tick Only, and Hide. Tick and Line is what you see in a typical string—a tick (or arrow) and a line to the object being dimensioned. Tick Only suppresses the witness lines, and Hide suppresses both, giving you a nice, clean string.
Even better, let’s say I need to add a beam to this bay. I can just put it in anywhere in the bay, use Edit Witness Lines to add it to the string, and reset the EQ switch. Just like that, the spacing and segment lengths update—no need for entering any information by hand.
Our final topic today is modifying the dimension text. Often you need to add a prefix or suffix, or replace the measured value entirely. If you select a dimension and single-click on the text, you’ll see the Dimension Text dialog.
Most of these fields are self-explanatory—it should be obvious what adding text above or below the value will do. But here’s an example:
You can also override the measured value—with text only. If you try to enter a new number, Revit complains. It knows it’s bad practice for a dimension to have a displayed value that doesn’t match the actual value.
Sometimes you do need it, though, either to completely wipe out the number or to show some value, such as “0.” In those (very limited) cases, you can use the trick of right-clicking in the value field and choosing Insert Unicode Control Character. (I prefer the Unit Separator (US) myself.) It adds an invisible text character to the field, so you can then enter whatever numbers you need.
Just remember: Use this power wisely! The next person who reads your drawings will thank you.
For more Revit dimensions tips, visit http://www.cad-notes.com/2009/10/revit-annotations-dimension/.