Unitsosaurus: Set Up Revit for Success

Spurred on by a bit of tweetie-bashing of file conversion qualities, or lack(s) thereof, and by seeing countless individuals (CAD and BIM “Managers”), thus projects, teams, AND finally, firms that can’t get simple geometry straight… literally (see every CAD drawing ever)… well, this mediocrity of basic quality is rampant in Revit® and further, BIM, to an all too large degree. If your units are set up like Figure 1, then you are dismissed lol… everyone else, be very scared, but read on.

Figure 1: Image illustrating proper overall units

Okay, so since you are still here I hope this will clear up a few ideas or at least give a starting point for more research into quality, precision, and what it is we are doing in AECO.

If your Revit project template’s units (today we are talking Revit, but I do not care about the software: set Units as granular as possible) are NOT set as shown in Figure 1, and they are more like Figure 2, set your units up as I will explain. IMMEDIATELY after reading this. NO JOKE!!!

I will hold back on much more editorializations, except to say that if you disagree with any of these concepts, please contact me on twitter @JayZallan and try your best! I dare you… fwiw I have geometry, floating-point precision, and quality in my corner.

Do you have any “Wall is slightly off axis” or worse yet “Line is slightly off axis” warnings? “Slightly Off Axis” warnings are directly related to mediocre, or just plain bad, modeling. If you use any CAD drawing in your process, you will most likely have found these files are some of the causal factors (and if you’re still reading have ignored such Revit warnings). Regardless, a BIM shall be correct, and not approximated or rounded to the 1/8” (or whatever contractual precision’s been set) until the dirt hits the shovel (AKA: during construction). Both bad modeling and bad CAD create bad BIM, which is costing your firm time and money.

So here we go—only tech from here on out.

  1. Do not use the following setup.

Figure 2: Image illustrating possibly the most unprofessional and unintelligent setup of units possible

  1. Set up Dimensions to respect Project Units.
    1. I am not saying leave dimensions that report to the x/256 of an inch.
    2. What I am saying is:
      2. Fix the model, do not override dimensions.
  2. I do create one Dimension Type that does nor use Project Units and rounds to 1/8” (if that is your contractual obligation).
    1. Make this rounded dimension red.
    2. Rarely use this for individual dimensions, where geometry dictates or when the site dictates odd angles, etc.
    3. Never use these for dimension strings. FIX THE MODEL in that case!


Setting up Revit units correctly and professionally.

  1. Type “UN”


  1. Click the button under the “Format” heading for “Length” and set up as follows.
    1. YES, 1/256”.
    2. “Suppress 0 feet” is cool to uncheck if you’re into that sort of olde-timey thing. I like it personally but still I don’t usually use it.
    3. Digit grouping makes numbers look as we like in the USA… commas and all.
    4. “Suppress spaces” is ok to check if you’re into that sort of thing.
      1. Please understand that this comment goes for all following Units’ dialogs as well, as I am not into suppressing spaces.

Figure 3: Image illustrating proper “Length” units


  1. Click the button under the “Format” heading for “Area” and set up as follows.
    1. Two decimal places.
    2. Suppress trailing 0s.
      1. This is key. One will only see extra 0s if there are numbers other than 0 to the right of the decimal (0s are visible in Temporary Dimensions and when OBJs are selected, but that’s how it should be. Let me see reality!)
    3. All the rest as shown.

Figure 4: Image illustrating proper “Area” units


  1. Click the button under the “Format” heading for “Volume” and set up as follows.
    1. Note: one may want to get more granular with this if refined calculations are desired.

Figure 5: Image illustrating proper “Volume” units


The following settings are even more important than the length settings, as we geolocate our models and need this granularity and quality. (Full Stop)

  1. “Rounding” set to “Custom”
    1. Place cursor between the 0 and 1, to the right of the decimal point.
    2. Enter “0” ten (10) times.
      1. Just do it, you’ll thank me when Shared Coordinates don’t blow up anymore (as if).
    3. Remember, the trailing 0s will only show up when the geometry is… well, let’s just say “probably needs work” (at best) and “is totally a joke for someone who calls themselves professional” (at worst).
      1. Just do it, you’ll thank me when Shared Coordinates don’t blow up anymore (as if).

Figure 6: Image illustrating proper “Angle” units


Settings are all in the following images. There are not many comments until “Time.”

Figure 7: Image illustrating proper “Slope” units. (Yeah, you can set them up for Rise/12, etc… these are oft modified to satisfy municipalities, outside jurisdictions, etc.)

Figure 8: Image illustrating proper “Currency” units (add the dollar sign!) I like to set it up like money (since that is what this unit is lol…) so I let the trailing 0s show proudly

Figure 9: Image illustrating proper “Mass Density” units. The next time I use these will be the first, so if there are any mass density experts reading this, please let me know if there are better setups


  1. New to Revit 2020, Time  and Speed are going to allow a lot of future capabilities and I am looking forward to it!
  2. Currently used in the new (and one day to be working properly) Exiting Path tools, with more potential functionality and workflows, beyond exiting alone for the creative masterminds.

Figure 10: Image illustrating proper “Time” units

Figure 11: Image illustrating proper “Speed” units

Units Conclusion

  1. Revit Units should look something like Figure 12, but if there are differences, a few things should (if not must, imo) remain constant: Length and Angle must be as granular as allowed, whether in Revit, CAD, or any other software used to author BIMs or any portion therein. Set the Units granular and then draw and model to rational dimensions. PERIOD ;)

Figure 12: Image illustrating a properly set up Units dialog

Jay B Zallan | Virtual Design & Construction Technology Conductor (& Fine Artist)
Jay brings wide-ranging design, delivery, management, mentoring, and teaching  experiences to the readily changing AECO industries, founded on an expansive 35 plus year career. He has focused on VDC planning, production, process development and research & development to help enable efficiency-generative creative project execution, delivery, and success throughout the AECO landscape. This JayZ is an educator, author and industry lecturer throughout the BIM world. He strives to inspire current and future generations to achieve and exceed beyond even their own expectations. Being a Fine Artist (large format oil and mixed media canvases), Jay adds unique and collaborative insights and perspectives to every team he is part of.

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