Tuesday, April 24, 2007

No Man is an Island

If you are considering moving to BIM, then you need to consider the bigger picture - outside of your office and outside of your discipline. If you're reaping the benefits of model-based design by pulling your elevations and sections from the model, that's great, but it's really not BIM. If you're getting automatic schedules and even take-offs that might be considered BIM, in a lightweight kind of way, but there is so much more that is possible.

Don't get me wrong - all of those things are great, but if you're TRULY looking for the holy grail, you have to remember that the "B" in BIM stands for "Building", which implies that there are a whole lot of other people involved besides you, with different informational inputs and outputs, all contributing to and accessing the building model.

The Revit platform is beginning to allow us to more easily collaborate between disciplines with a fully functional and transferrable model, allowing for all data and geometry to move freely between the various teams working on the project, even though they may have completely different uses for and ways of dealing with the model.

Revit Structure and Revit Systems add the Structural and MEP disciplines to the already mature Architectural product. While this brings us new capabilities and ways of collaborating, it also brings with it new responsibilities.

Communication is key. At a very basic level, all players need to be using the same version of Revit. If the architect is using Revit Architecture 2008 and the MEP engineer is using Revit Systems 2 (based on Revit 9.1), then the model will not be usable by the engineer. Revit products introduce a file format change with each and every release. You MUST communicate with your consultants and collaborators before upgrading your project to the new version. Hopefully all players are on subscription so that there will be little if any lag between the time the Architect is ready to upgrade and when his consultants will be ready as well. The good news is that the releases of Revit Architecture, Revit Structure and Revit MEP are nearly simultaneous - within days of each other.

You also need to be in agreement on how you will share the data. Will you provide files to link via FTP site? How often will the model be updated? What will be the protocol for dealing with conflicts? The list goes on, but my point is that you have to communicate, constantly and openly with the other disciplines and players involved.

You also have to be more aware of how those other players will use the data that you put in the model. If you're working with an MEP engineer who is using Revit MEP, you need to know not only that they can use your room information in their analysis, but also how you can easily streamline the process and ensure greater accuracy by taking a few simple steps. Revit MEP 2008 includes hooks to IES Virtual Environment, which can be used by the engineer to run extensive heat load and lighting analyses on the Revit model by exporting the data. Additionally, some of the basic functionality from IES is included within Revit MEP 2008, allowing for preliminary heat load calculations to be done in minutes, right inside of Revit MEP, with no additional software required. You can quickly explore the effects of building orientation, building materials, glazing, etc. to arrive at an efficient and sustainable design very, VERY early in the process.

However if you, the architect, don't prepare your model properly beforehand, you put the burden to do that on the engineer, increasing the time it takes to get those analytical results and worse, introducing more opportunity for erroneous results.

Here's a scenario: You create room definitions in Revit Architecture. As the architect, you may not really care about the 3D volume information of the room. You're just wanting them documented for area calculations, room finish schedules, color fills, etc. So you don't even pay attention to the Limit Offset property of the room (go ahead, pick a room and check out it's properties - did you ever notice that before, and if so, did you ever wonder what it was for)? The Limit Offset is the vertical limit to which room volumes are calculated if volume calculations are turned on in the Room and Area settings. Here's the key - the Limit Offset is NOT the height of the space - it is the limit of where the calculations can occur. In Revit Architecture 2008, floor slabs, ceilings and roofs can now be (and are by default) room-bounding objects. This means that when the engineer runs his analysis, the room volume will be calculated based on the walls, columns and curtainwall room bounding objects, as well as roofs, ceilings and slabs. If you have a model that you migrated from an earlier version of Revit Building, however, those slab, roof and ceiling objects are, by default NOT room bounding. And if you leave your Limit Offset set to a value that is below your ceiling, roof or slab, it doesn't matter anyway! It's a simple matter to select all rooms, set their Limit Offsets to a value that will accommodate all horizontal bounding objects and select any "legacy" slabs, roofs and ceilings and toggle the room bounding property on. But you need to remember to do this. Yes, the engineer can do it, but what if they don't? What if they just assume that you, the architect, did that, because after all - it's YOUR model that they're getting the information from? (Hmmm... who would bear the liability for any errors due to an oversight like that? I honestly don't know - but that's a topic for a whole 'nuther post...).

The above is just one example of how simple communication and just a bit of understanding about cross-discipline collaboration needs can go a long way to streamline and improve the Building INFORMATION Model. I haven't even touched on interference detection between architectural, structural and mechanical systems, or how you can collaborate with users of AutoCAD-based products (like your Civil Engineer, for example). My intent here was to merely provide some food for thought.

I am hoping to present a 90 minute session on cross-discipline collaboration and coordination in Revit at Autodesk University this year - stay tuned for developments!


Blogger Heather said...

How to change the Symbol of Elevation in Revit?

The symbol of Elevation is System Family. It just has two types (Building Elevation and Interior Elevation) and it is different from Standard symbol.

2:53 AM  
Blogger Matt Dillon said...

Unfortunately, the elevation symbols are the one annotation symbol that cannot be customized. Some people have worked around the issue by "faking it" with custom schedule tags.

My attitude is that they're just symbols - they convey the same information, they just look kinda dumb. Hopefully there will be the ability to modify them in future releases but for now, that's all there is...

6:41 AM  

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