existing conditions, part 2

Last month, I left off with the deliverables that we received from our surveyor.

Our first step was to convert all of that information into an existing conditions Revit model. We started by converting the 3d AutoCAD model.

Our two priorities in the conversion were (1) maintaining geometric accuracy and (2) creating a usable Revit model. There was no option: they could not be mutually exclusive. And we did it. It was not easy. And it hurt. Furthermore, the results are not ideal - mostly because the model is really finicky. But it was the best we could do.

To maximize our results, we had to develop a unique (but integrated) process for converting each type of object.

The existing building mostly contains 1567 CIP concrete columns (all unique); 476 CIP concrete beams (again, all unique); 31, 492 LF of various walls (mostly CIP concrete and brick); and 816,995 SF of undulating concrete floors.

And we did it, all while referencing the TruViews to make sure we were interpreting everything as accurately as we could.

I've simplified the process quite a bit - there was a lot of planning, organizing and optimizing that went into it along with a lot of technical skill. This entire conversion took about 3 weeks, with one person actively modeling and a secondary person doing some modeling and some organizing.

The next step: laying in new structure and architecture, which was designed based on inaccurate existing conditions.


Miguel Krippahl said...

If I understand correctly, you had to convert an Autodesk Autocad 3d model into an Autodesk Revit model BY HAND?
3 weeks?
Shouldn't this process be automatic, or at least semi-automatic?
After all,Autocad and Revit are two AEC products from the same software manufacturer, so you would expect at least some degree of compatibility.

Well, I admire your courage, and effort, of course.

Laura Handler said...

Yes, we did convert it by hand, so to speak. We were able to use some of the features in Revit to facilitate the conversion, but nothing was automatic.

Should it have been? Probably.

As much as I want AutoCAD and Revit to speak to each other, I am trying to understand that Autodesk acquired Revit - so originally, they aren't from the same software manufacturer. Either way, it is frustrating.

Dustin said...


This is awesome...I can use a lot of use from a process like this.

I wish that was an automated process, but even if it was I am sure there would be a whole new set of issues to deal with.

I was curious about when you say you created 1567 unique columns...did you do this as 1567 different types or did you create 1567 instances of 1 type?

Also, did you link in the 3D AutoCAD file into Revit for reference? Or just reference it from AutoCAD?

This is a process I can see us using on a future project to test the use of a 3D scanner out.

Dustin said...

A correct from my comment

I can SEE a lot of use from a process like this.

Laura Handler said...

It was actually 1567 different families - and we used the AutoCAD model in a variety of ways.

peter said...

Since you used navis and that is now owned by autodesk, could/should there be a way to round-trip this somehow? What does trueview do that navisworks doesn't? I imagine that the revit graphics engine would not be able to cope with a Leica scan, so you'd need an interim better graphics engine?