COMMENTS
What are estimators estimating? Are they estimating quantities? Or are they estimating costs?
Would an amount of concrete poured on job A cost the same if it would be poured on job B, ignoring any differences in complexity between the two? Surely not.
I agree that getting the quantities right is an important part of the job of the estimator. And it is absolutely necessary to get them right. But it’s only the first stage and once you get there, that’s when the fun really starts.
So an estimator would be more productive if reliable information can be taken from the 3D model without much effort. But the estimator wouldn't be out of a job.
Just my 2 eurocents.
I agree with Johan Bastiaansen. The act of estimating involves more than mere quantities. Interpretation,organisation and presentation of data in a coherent, cohesive and cognisant format still requires somebody like an estimator. My 3.18 USD cents worth.
Thanks for your reaction, Johan and Herman. I do share your opinion: determining the cost of a project does require an estimator!
The point of the post is not that BIM makes estimators unnecessary, but that the available technology will make it possible to spend more time on determining and analyzing the cost of the project, because less time has to be spent on taking off quantities and explaining how quantities were calculated to the project team.
Cost calculation will still require the expertise and construction know-how of estimators - the difference is that his or her time can now be used more effectively.
BIM has a lot of Promise for the industry, and One of the best tools to use is Building Explorer.
www.BuildingExplorer.Com
However there is a fundemental problem implementing BIM Designs that a program can read and produce a viable resulting estimate and schedule reliabley. The crux of the problem is Engineers are going to have to become less lazy and put thier designs on paper or PDF's so the system can see them. This use of Performance Specifiactions and the practice of never designing the lay our of Conduits and Sprinker pipes just touches the tip of the issue to explor and cheer lead the insustry to do it differnetly.
While I also agree that it will require an estimator to determine a final cost. I don't think there will be estimator(s)(plural)in a large firm. There won't be a large demand for estimators which will lower salaries as well. The cost of the BIM generated takeoffs (going to the architectural firm) will probably be just over the cost of your current estimators salaries. Don't be fooled. The estimator will be on the dangered species list in the future. My 318 cents.
Surely the BIM should be built by the design team of Architects and engineers? Are they not the "DESIGNERS"?
why are you requiring duplication of work, adding yet another set of data?
Not only do we have design team model, a visualisation models and a construction models but now an additional estimating model?
Surely the BIM process should streamline the production information process, not add yet another set of data that needs to be synced with all the other design data evry time a design change happens?
Are you not adding yet another area of risk that needs managing, because somebody didn't define the process correctly and ask the consultants to produce the required data in the required format in the first place?
The BIM process should be about a streamlined methodology where common data is used throughout. There may well be need for education, training and improved workflow. Along with definition of how the data should be delivered to the construction and estimating team.
A series of tools to manipulated that data to add 4D, 5D and beyond would be required to enhance the BIM. But creating yet another model.
Providing automatic take off is just a bit of programming or scheduling, combined to produce some quantity data, With a bit of VB etc.. even I can do that!
The estimators skill is then what they do with this data. Quanities is only one part of the equation. Hopefully the days of the estimator who spends all day just tracing or scaling lenghs etc is gone.
But that should have happened years ago as much of the data required could have been delivered from a few AutoCAD polylines and a bit of block attribute extraction.
BIM should be about enhancing common data whether it be from the Client, Designers, Estimators or Contractors. By everybody creating "My BIM" you are surely increasing cost, risk and liability?
The MyBIM culture that is developing is replicating the existing work processes and prejudices. The application of BIM as a tool keeps everybody in their silos, just a different CAD tool. Only the single discipline benefits, or does it, no absolute proof is offered. My drawings are cheaper or I get good visualisation misses the point about the he NIST report comments on collaboreation and interoperability.The only people that benefit it seems to me are the companies that offer modelling services to find clash and some basic material measurement. BIM is about changing the way the industry operates, changing the mindsets and changing the outputs so that everybody wins. It is above all about collaboration and reuse not redo and rework.
I have to agree with those comments that recognize the value of a professional estimator to interpret the data and design intent that has been incorporated in a model. The caution of this emerging technology with BIM is to manage the expectations as another tool to arrive at an accurate prediction of cost and not a replacement of the estimator. Unless the model is complete (and by definition the conceptual, schematic and design development stages of a project are in-progress models and not complete) there will always be a need to interpret by an informed and experienced professional the information available at each stage of a model to assess risk, cost, constructability, and suggestions for improvement in achieving design intent. I personally embrace the benefits of the BIM model in that it prompts more informed understanding of design intent and facilitates more evaluation time and effort to quantify the project that has been a duplication of information already available, therefore enabling the Estimator to increase their value added to the project team.
Regardless of which program one uses, modeling only gives a very generic flavor for what is being built. Even though BIM may bring us into the next level of understanding the design intent, it will not replace the intricate and necessary understandings of what it takes to build the proposed product, something only the human brain can interpret.
A good estimator will visit the job site, understand the site constraints, the neighborhood, traffic patterns, the soil, etc. Then they will interpret the plans and put into a number what it will take men, materials and equipment to build. Even the best modeling database that anyone can build will not adjust for the individual factors that are inherent to every project. Whether it's earth, concrete, carpentry, steel... each project will always require a estimator to be able to adjust for the specific project.
As someone who is experienced in design and has produced estimates using 3D modeling for material take-off, I really can't see BIM or any other use of a model having much impact on the need for experienced estimators. Most projects require various levels of estimating accuracy long before a model has begun to be constructed. Final estimates usually benefit greatly from utilizing the model for MTO as well as connection data (i.e. welds, bolted connections, etc.)and material handling with their associated labor costs. These costs vary from project to project and site to site. There are many other factors in a quality estimate that are only marginally affected or not affected at all by model generation or change.
Quoting your statement:
"When project teams define and agree on the content, methodology and naming conventions used in design models, these models can provide usable input for quantity takeoff"
This is the sticking point of the whole discussion. I have found that it is standard business practice to be working with design teams that can not be consistent in their nomenclature even within the same company, let alone the same design team or project team.
Without that standardization, getting reliable data from BIM Models, with any sort of estimator time savings is a crap shoot at best.
Chris,
I agree with the point that you make: establishing standards and communication guidelines indeed is a crucial factor in successful use of design models for downstream tasks such as quantity takeoff, cost planning and schedule planning.
At Vico, we have worked with a number of companies to achieve exactly that. Throughout the projects that we participated in, standardization of content is done by means of a Model Progression Specification, which not only specifies WHAT needs to be modeled, but also WHEN and HOW. Specifying the WHEN and HOW, as well as responsibility for the various types of content results in the process improvements described in this post when all parties involved agree with the guidelines and follow the plan.
In your projects, have you deployed specifications to improve the results of BIM for quantity takeoff and estimating?