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The Zen of Clean

When I first saw Autodesk® Revit® in early 2000 I immediately saw the end of dwgs in AEC. Unfortunately they are still A) useful for a few limited actions; or B) a security blanket that some cannot seem to let go of, etc.

So in a selfish attempt for me to see projects unbloated by dwgs and the multitudes of horrific drafting mistakes and origin issues that seem to pervade AEC (don’t argue yet; check your dwgs for  lines off axis at the highest tolerances. Oh, are the dwgs only drafted at 2 or 3 decimal points? You’re probably about to hate that you’re checking all this!)

Quality In = Quality Out

The first rule of using dwgs in Revit:
Never Import dwgs (or other such files) directly into Revit. If you must use a “live” dwg, then always link them (but as you’ll read, that too is less than optimum).

Want peace?

The second rule of using dwgs in Revit:
Use only clean dwgs (if you must use them at all). Talk to some folks and be told "never use .dwgs in Revit projects!” Whereas I agree in principle I also know that too many folks in AEC are still hooked on dwgs. And there are a few acceptable uses such as creating a topography.

If one must use dwgs, etc. “live” and it’s truly only temporarily and not for generating topographies (which should only use the “Clean and Link Method”), then who am I to argue? That said, if the files will be leveraged for more than, say, two hours; then absolutely use the "Family Method.”

The Family Method

Clean the dwg as below:

  • Import the cleaned dwg into a family
    •           a Generic Model Family perhaps
    •           Origin to Origin
  • If any future modified dwgs need to replace the current dwgs, and the origins and cleanliness remain, then it is a simple affair of deleting the old and re-importing the new. If not, SNAFU.
  • Load into the project.

Revit thinks about and works with Families better than it does with live dwgs.

Whenever one receives a .dwg file from anyone these processes are requisite prior to any use in Revit. If these processes are not followed, do not—I repeat, DO NOT—bring any external .dwgs into a Revit project directly, if you know what's good for the project.

Is that my opinion? Yes, but it has been verified by so many others with so much evidence of its necessity that it might safely be deemed fact.

Also understand that the .dwg invariably will have lines not on axis so in those cases you will be hinging Revit geomety onto garbage that is not just useless, but actually damaging to projects, teams, and brain cells, so please don't use them! That said, here is a best-case-for-a-worst-case process …if you must...and you do not…
 

Cleaning .dwg Files | Prior to Use in Revit

The following are procedures to accomplish for each and every .dwg (etc.) file, prior to linking into or using anywhere in Revit. This will ensure (among other things) that all geometry is within 20 miles from .dwg Origin of 0,0,0.

Notes and Tips:

If, during any of the “Zoom All” commands below, it appears that the screen goes  blank and you do not think you see geometry, think again ;) The geometries are so far apart that an entire site (or whatever geometries you have) can appear as only one single pixel. In this case draw a line from 0,0,0 to the top/right of the current view and you should be able to track your geometry for cleaning... which are most likely at that top/right ;)

If any steps are skipped then please expect to do the entire process again!

  • Verification of the 20 mile limitation is immediate and automatic in Revit
  • Non-cleaned .dwgs are never to be used in a Revit environment
  • Non-cleaned .dwgs create Revit file corruptions especially if over 20 miles from origins. You have been warned!

1.       Who is to clean the .dwg?

  • Preferred Method – Everyone cleans their own files prior to sharing
  • Communicate and coordinate this paper and processes with consultants to have their files be cleaned per below constraints, prior to sharing.
  • Most Used (aka: Horrible-Teamwork Method) – the team that cares the most about good work cleans everyone else’s files.
  • Ugh.

2.       Preparing the .dwg

  • Turn all layers on
    • Layon
  • Thaw all layers
    • Laythw
  • c.       Unlock all layers
    • Via the layer manager (preferred method)
    • Layulk is sometimes useful for one-offs

3.       Remove all unnecessary geometry (Yes, in multiple view types)

  • Top View
    • “Zoom All” (This is distinct from Zoom Extents; Zoom Extents can be told to ignore actual geometry)
    • Verify that only the project geometry is on screen
    • Delete any/all unnecessary geometry (and I mean ALL)
  • Elevation View(s)
    • “Zoom All” (This is distinct from Zoom Extents; Zoom Extents can be told to ignore actual geometry)
    • Verify that only the project geometry is on screen
    • Delete any/all unnecessary geometry (and I mean ALL) –Hmm I see a motif ;)
  • 3D View
    • “Zoom All” (This is distinct from Zoom Extents; Zoom Extents can be told to ignore actual geometry)
    • Verify that only the project geometry is on screen
    • Delete any/all unnecessary geometry (Now ‘you’ mean ALL)

4.       Save

5.       Purge All (This may need anywhere from one to four+ passes of purge to get rid of all “purgable” items)

6.       Verify that all unnecessary geometry was truly removed. If any unnecessary geometry exists, go back to steps under #3

7.       Purge All
8.       Audit

9.       Purge All – Yes, purge again and over/over until there are no objects that can be purged.

10.       Save
11.       Close

Now one can use the cleaned .dwg in Revit. If you must... 

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