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Saturday, August 22, 2009

Coinstruction - Model Based Estimating to Inform Target Value Design #BIM #Estimating

This article is pretty intense. If you've ever gone over budget in the design phase, you may want to read it and see where the future's going. When I have the conversations with people about CAD vs BIM, I'm doing it from my contractor background point of view. So, my posts about CAD bashing were all lead ins to these posts. There's just so much more you can do with the model than with 2D lines.

Ah, I think I figured it out. If you want the fastest way to draw 2D lines to represent plans, sections and elevations for a building, probably AutoCAD is your solution and the perfect software. If you want to create an intelligent model for energy analysis, clash detection, estimating, fabrication, scheduling and facility management, pick Revit, IES, Ecotect, Navisworks and my many estimating programs at www.bimcycle.com.

The way I see it, you have to work backwards, and the current workflow doesn't work. If you start with the owner's budget, you need to figure out what you can build with those funds. If you have the space, height and building use information, it makes sense to bring in the contractor and subcontractors to use their building and pricing experience to make the recommendations of what materials and methods would fit within the budget. Once you have that information, then the architects and engineers can use that information to design the building and stay within the construction budget.

It seems like now it's more like Design, Bid, Design, Bid, Design, Bid, Design, Bid, Bid, Bid, Build. That doesn't seem to be the most advantageous way to build the building. Using BIM, the team (including architects, engineers, consultants, LEED AP, contractors, subcontractors and suppliers) can all work together to reach that goal far faster and easier than from today's linear workflow. I've even come up with several names for this great new idea that I just invented. Yeah, I'm thinking of calling it Lean Construction or Integrated Project Delivery. Hold on....darn it...i just googled those words and apparently, someone's used them already.

Ok, how about Coinstruction. Building a building and having accurate costs down to the penny.

Well, I have good news and bad news about my new word "Coinstruction." First, I didn't see any references in google to the word being used for AEC, so I did invent a new word for our industry. On the down side, there are 1,000 references to coinstruction for a toy for children. You can see the pictures here. Maybe I'll give these out as gifts included with every copy of AutoCAD we sell. How about Revit, the software for change and coinstruction.

One of my phrases I use with contractors is "Why do you call it an estimate? Shouldn't you call it an accurate?" Well, I think with BIM and especially adding a layer of IPD, we'll get a lot closer to accurate for bidding.

If someone offers you a penny for your thoughts and you put in your two cents worth, what happens to the other penny? It goes into the bank, because a penny saved is a penny earned. And that, ladies and gentlemen is why contractors are embracing BIM at an astounding rate, because all of their investment in Revit, Navisworks and converting CAD to BIM for clash detection is earning them a hefty ROI. Did you know contractors are getting between 200 and 500% ROI on BIM investments. The CM at Risk contractors are gaining the most from the process of converting CAD to BIM. it's also becomes a profit center in selling the owner a 3D intelligent Facility Management model.

Now, on to the article. I've just put a few paragraphs here, as it's a really long article, even by my standards (and some of my posts).

http://www.aecbytes.com/buildingthefuture/2009/ModelBasedEstimating.html
(August 12, 2009)
Model Based Estimating to Inform Target Value Design

Saurabh Tiwari, Josh Odelson, Alan Watt, Atul Khanzode
DPR Construction

The use of Target Value Design (TVD) or Target Costing is one of the focus areas of the application of Lean Construction methods to large healthcare projects. The Lean Construction Institute defines Target Costing as a practice which incorporates cost as a factor in design to minimize waste and create value. The cardinal rule is that the Target Cost for a project should never be exceeded. In most traditional project delivery approaches, cost follows design, but on projects where the TVD approach is used, cost should dictate what gets designed to ensure that the target cost is not exceeded. As a result, rapid cost feedback to the design team is paramount in this process. One mechanism for providing this rapid cost feedback is extracting quantities from the virtual model and model-based estimates. In this article, we discuss the lessons currently being learned in applying Building Information Modeling (BIM) tools, such as model-based estimating, for TVD on a large healthcare project in Northern California."

Why Model-Based Cost Estimating?

In the Target Costing process, cost should be an input to design. There has been a lot of research on how to make this happen. Teams have used organizational approaches, like bringing a group of cross-functional team members together in an IPD team, to be able to provide this rapid cost feedback. Cost feedback based on a BIM has also been suggested as a potential option to rapidly iterate through the design options (see Glenn Ballard’s “Innovation in Design” Presentation available at the Lean Construction website). Stanford University’s Center for Integrated Facility Engineering pioneered the concept of estimating based on a product model in early 2000.
Model-based cost estimating is the process of integrating the object attributes from the 3D model of the designer with the cost information from database of the estimator. Model-based estimating has proved to be a leaner approach compared to traditional 2D drawing-based estimating. Using the 3D model to estimate rather than the 2D drawings utilizes the object attribute of the 3D model rather than “assuming” the same, based on flattened 2D drawings. The process is not only quicker but also eliminates scope for errors and omissions. Figure 1 compares the two processes and shows how the cycle time is reduced from 8 weeks to 3 weeks.


Read the rest....I really think every architect especially needs to see this if you want to know why the contractors are winning the war and getting more design to build projects:
Model Based Estimating to Inform Target Value Design: AECbytes "Building the Future" Article

By the way, I'm working with some of the vendors mentioned in the article and a few others. Drop me a line if you'd like to explore these options for yourself. One really easy option now is Reed's QTO product. It's more for design phase costing especially for architects. It's only $500 (and $250 if you have Reed's SmartBIM Library Manager) so it's something you can even market to owners that you've made an investment to help them come up with better conceptual costing.

1 comments:

Erik August 23, 2009 at 8:34 PM  

Oh Greg, you have been hanging out with (or at least talking about) the CAD-ies too much lately. ACAD is faster to draw line for plans,sections and elevations? For shame....

I'm pretty sure even the best CAD jockey can't have a wall represented in plan, section AND elevation in the time it takes for me to draw the same section of wall in Revit, even ACA can't match Revit (although it comes close.)

What you don't have to do in CAD is represent it CORRECTLY. You can draw one thing in plan, another in section and another in elevation (although it's more likely it will be three seperate drafters, rather than one.)

If that's what you want, then by all means...

But I'll take Revit (or some other BIM authoring tool.)

Keep 'em coming Greg.

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