From my old blog...
I've been inspired by a recent thread on the AEC-IS Roundtable forum to discuss the topic of collaboration, digital file disclaimers and risk management when employing Building Information Modeling tools. I recently met with Jim Bedrick, Director of Systems Integration for Webcor Builders in California to discuss related topics and I credit the inspiration for this thread to his Roundtable responses.
Most, if not all practicing Architects and Engineers use a Digital File Disclaimer when transmitting CAD files to clients, consultants and contractors. These disclaimers function as the buffer between the designer's intent and the builder's means and methods. To put it bluntly, disclaimers absolve the designer or engineer of any liability due to errors or omissions in their digital data. Most disclaimers also state that the accuracy of such data cannot be guaranteed. Where does this leave the state of efficiency in collaboration? See the NIST Report on Interoperability or Paul Teicholz' article on Declining labor productivity in the construction industry.
Think about what that means to a contractor when you send him/her your CAD files or BIM model and you state that none of the lines or model objects are guaranteed to be accurate. Guess where that data will go... Herein lies the problem: today's liability and insurance requirements restrict the Architect or the Engineer from dictating means and methods to the builder, thus we must take a more focused look at our methods of modeling and documentation in a collaborative environment.
While movements are underway to change the way projects are delivered, in effect distributing risk across an entire project team (result-driven), I believe the A/E sector can begin to re-examine its current collaboration process with upcoming BIM software. To begin, builders like Mr. Bedric are imploring designers to avoid 'fudging' practices such as overwriting dimension string values in CAD files or widely using terms such as "VARIES." If the A/E industry can formulate a loose set of best practices for BIM, we will make great strides towards improving productivity and the usability of our data by downstream consumers.
As far as production cost savings are concerned, Mr. Bedrick believes that reducing the time and effort required to produce shop drawings by reusing design CAD/BIM data is insignificant; however, true value can be harvested by efficient use of a RELIABLE digital model in order to provide faster, more accurate quantity take-offs. This would drastically reduce the turnaround time on estimates and would allow for either lower pre-construction fees or more frequent cost estimates which would potentially "reduce or eliminate value engineering efforts resulting in rework for the Architect."