Monday, July 02, 2007

Converting CAD Details To Revit Details: Just Do It...One way or another.

Before you read on note that there is a companion to this (or as you may find a replacement)... RIGHT HERE... added 07-09-2010...

First off thanks to Nike for unknowingly letting me use their old slogan.

Yes, the following are all 2D detailing methods for Revit!!! We can talk about leveraging our model for project specific details based off the 3D geometry later: that's a different diatribe... Also please note: All times are empirical estimates and are placed as general guides, to be used solely as approximations, as I have no way to know how your teams can or will perform, how detailed your details are, etc., etc... Now on with the show.

There is a question that seems to always come up about what to do with existing and/or typical CAD details in Revit. And that question is...
What to do with existing and/or typical CAD details in Revit?

Do we redraw them (Can you say Intern?), do we Revitize them or maybe just Link the CAD files in and continue to edit them outside of Revit? Let's take a look at these options, shall we?
  • Plan A: The "In a perfect world" approach. -Draw (and/or redraw) all details entirely in Revit.
      • Ensures the cleanest Revit geometry (hopefully). (This approach can be expected to yield the antithesis of what can happen in plan B when the CAD data is bad. For the results of some 'Bad CAD' data see Image 1).
      • Details will be formatted and can be saved into project templates, pre placed on sheets and just waiting to be printed!!! Or we can use FILE / INSERT FROM FILE / VIEWS... for another method of propagating these, now existing views, into other current and future Revit projects.
      • Devise a projected time line within which to accomplish this by. Remember; eat the elephant one bite at a time, it's the only way to manage this and not freak the whole office (or boss) out! An example is: If The office has 1,000 details (traveling West at 65 MPH) and Johnny manages a team of 5 users (and 3 of them play hockey) and each user draws 1 detail a day: When will they be in Chicago?...Uuummm I mean, when will they be finished? They will be complete before 1 year comes to pass [200 work days to be in Chicago...not bad]...Hey here's a good idea for a team vacation incentive: Complete the detail work in half the time agreed upon, while still getting 'the work' out. Details done, morale high.
      • If you are on a 1-2 year plan to fully implement Revit then this method will help you enormously!!! Each detail should only take 1-4 hours once a good work flow is obtained. -Since these are quite often details that we already have elsewhere and we can print them...
  • Plan B: The "In a nearly perfect world" approach. -Revitize CAD details that you already have. (See Images 2 through 10 below!!!).
      • This consists of turning the CAD data into Revit data.
      • If your CAD teams draw (in CAD) with 8 decimal place precision, and they are always drafting perfectly, mindful of their snaps, etc., etc., etc., then what's shown in Image 1 will never happen, making this Plan = or > Plan A.
      • BUT!!! If your CAD teams draw with 1, 2, even 4 decimal place precision then all bets are off and I can almost guarantee that you will see errors! In the cases where Plan B yields less than perfect results you need to Review Warnings!!! very carefully and often to ensure that no errors show up in your actual projects...PLEASE don't let that happen!!! (Remember this later when I talk about my "Paranoia Abatement Protocol" AKA: The Old Test Project...Don't Revitize a CAD detail without it!!!).
      • Once a good work flow is obtained this could take 1/2 to 2 hours per detail.
      • Details are now Revit formatted just as in Plan A.
      • Devise a projected time line within which to accomplish Revitizing all CAD details by. My 'Chicago algorithm', the elephant and the 1-2 year plan benefits are all still applicable to this approach as well as for Plan A (Yaay)...Though the math for this option may be as little as half or better. Again, depending on the users, the CAD data, etc.
      • Sounds enticing and maybe exciting...and perhaps it is. I suggest at least a test by the same Revit user, where they take 2 sets of similar details; maybe 3 details for each option. See which works best for you, your standards and your office...
The now famous 'Image 1'
  • Plan C: The short-term, temporary or "Oh Shit, just get them out the door" approach. AKA: The "We'll get to it later" method.
      • Link (not import) the actual CAD files into separate drafting views. Fast to link but could (will) pose more work when wanting lines to import 'correctly' etc...not the end of the world but if it's not already set up and you have to print NOW you're F#@*ed.
      • Possible issues with text, leaders...But if it's "Oh Shit, just get them out the door" then we gotta do what we gotta do...
    • When (or if) you use this method, remember that when you use the Detail Callout tool you will need to choose the "Reference other view" from the Options Bar & then pick the correct drafting view from the drop down list.
      • Keep putting Plan A and/or Plan B on hold and you may find your teams are wasting so much time opening, panning, waiting that you schedule that in-house meeting where you, or others roll out the "Today we begin Revitizing all of our details" project..."Who would like to volunteer?...Yes Johnny, later is today"
      • Obvious method for when the clients or planning commissions, etc. need info before it was planned and/or scheduled for.
The detail I used herein is very simplistic with few lines when compared to most construction details I have come across and still it generated 30 errors!!! (As seen in image 1) Yes, the 30 errors "(may be ignored)" but being that the lines are all "slightly off axis and may cause inaccuracies" that is just too much risk for my liking or for me to take into the future of my projects, if I can at all help it.

  • Begin a new, blank 'detail creation' project. (Not a real Project!!!)
  • Create a new Drafting View.
  • Name it now (it's best at this point, especially if you get into a "production line" mode. It can help make this Revitizing, transitioning faster.) we can always change the scale later.
  • Open that view and Import the CAD file there. Image 2.
    • Remember, Linking is Plan C, so make sure to Import.
  • I inverted the colors and let all else be default.
    • Leaving the CAD in color makes it easier for me to see what I have already changed and what I have yet to change...
Image 2
  • Explode (full) See Revit Help and search for 'explode' to find all you...maybe...need to know.
    • Note that by using partial explodes you may be able to shave a little more time off of this process, depending on the consistency of the CAD files, etc...
  • Select all the linework and change it from the CAD's styles to one of Revit's own. Image 3.
    • Usually I adjust the lineweights later in the final, clean, project version of the detail but that's your call.
  • Convert in this same manner any CAD hatch patterns.
Image 3
  • Convert in this same manner any CAD Text styles and recreate all leaders. Images 4 & 5.
Image 4

Image 5
Hide all (now Revit) text and leaders. Image 6.
Image 6

Delete all exploded CAD leaders and arrow head remnants. Image 7
Image 7
Unhide all hidden objects. Image 8.
Image 8
  • Verify by selecting everything and hitting the 'filter' button. Image 9.
    • If you only see Revit items listed then...
  • Hit CTRL/C (Copy to clipboard).
    • Now it's the time for the Paranoia Test.
  • If you see legacy CAD names, etc. go back to the cleaning & converting until it's all clean, Revit geometry.
Image 9
  • Open another new, blank project.
  • Create a new drafting view & open it.
    • Its name doesn't matter here, since this is just for testing purposes.
  • CTRL/V (Paste from clipboard).
    • Here comes the test:
  • Select everything and hit the filter...what do you see?
  • If it's all Revit geometry, etc. then this detail is now safe for project use, if not then something slipped by, but don't worry: this extra little step disallowed your project from becoming muddied by CAD data.
  • Image 10: the final detail with lineweights adjusted...
Image 10
Oh Shit, I nearly forgot: do you really want to F#@* up a Revit Project? Explode a lot or just one large CAD file directly into your project...Don't do it!!! It CAN be tracked!!!



  1. how bout the line too sort error message? how u encounter that error? thanks :)

  2. In regards to: Anonymous bout the line too sort error message? how u encounter that error? thanks :)
    Firstly why be so anonymous...I just have a problem with that but that's my problem, I guess. Now on to your comment... I try not to encounter that and if i do i must have a line that's too short...SO I GET RID OF IT. CAD dwgs are really not a good working method for Revit...That was why my suggested first choice is to REDRAW DETAILS in Revit.

  3. I was reading your hints for revitizing and I don't see where I can selectively hide and unhide Revit items as commented about in Image 6 and Image 8.

    Other than these two items that I cannot find (this is part of my Revit shortcomings not the blog) this was a very helpful blog subject.

    Sorry, but I had to post as "anonymous" because IT blocks access to certain types of sites - Gmail, etc... so I could not sign up for an account to post under.

    Thanks for any feedback.

  4. Hi, thanks for the nice words...sorry (to all) if I came across like an ass regarding the anonymous thing, as I said that is my personal's just that I can't reply directly to anonymous commentors unless they include their email addresses in their comments... Oh well...

    So on to business.... I used the Temporary Hide (the sunglasses) at the bottom of Revit, just below the drawing window... remember the temporary hide is just a working hide and will still allow stuff to print!!! Have fun all u Reviteurs (not reviteers...too disney!!!) -J

  5. Great in-depth post on this difficult process. Well written, not confusing for anyone of any skill level. I work with the McGraw Hill Sweets Network, an online database where you can find all your cad details needs.

  6. how to covert from cad to revit image3...?

  7. In principle, a good happen, support the views of the author