Upgrading to 2011: Deleted Levels!? Broken Plan Regions!?

So I came across this error quite by accident. The good news is if you don't care about the explanation, you can stop now and safely ignore the warning/error (shown below) that might be posted when upgrading a file from any previous version of Revit.

So what might you ask is going on? I'm glad you asked! :-)

As I said the short story is that this error is harmless (as far as anyone knows). I've now seen this error show up in three different models, two from 2009 and one from 2010. At first I wrote it off, as the first two models were not 100% familiar to me, and I assumed it was some type of error related to the files, and something the user(s) had done. However, when the error(s) above showed up in the model from 2010 I started to wonder as I'm much more familiar with the 2010 model.

So, off went an e-mail to my Autodesk contacts... and low and behold we've got ourselves a reasonably straightforward answer.

<snip>This warning is a result of fixing one of the bugs I was assigned right before code split. Basically, when the slanted columns project was originally done, a level id was stored in the view range dialog used by plan views and plan regions. At some point, the design changed, but the data was left in place. Somehow, and I’m not sure how, lots of plan regions are storing a stale element id. That was the source of the bug I was assigned.  This warning just indicated this is such a plan region. It can be ignored. There should be no consequence to the user.<snip>

So, basically when they first wrote the code for slanted columns the data mattered, but it doesn't anymore. Now we get a warning that is meaningless. If anything I think an example like this really illustrates the complexity of a piece of software like Revit. One might argue that they should be doing a better job of making sure random bits of data are not stored (taking up space) but given the complexity of such things, its not really surprising. A great deal happens as they write the software, and just like architecture and engineering the design changes. Have you ever sat there looking at a drawing, wondering how a design decision was arrived at....? Decisions and changes get made, and sometimes we loose track of the history and process, we're then left to clean it all up later on down the road.