BIM and Cost Estimating
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Dick Bates, Ryan's CAD Manager, uses this example to explain the difficulties associated
with quantification from a design model. “For any given wall, we need to calculate three
numbers to get a price: the gross area of one side of the wall to get material quantities
totaled for each wall type, and then the double gross and net areas to quantify finishes.”
The programmatic link between the two solutions means that Innovaya’s solution can
count and calculate materials directly from the Revit building information model. The
quantity extraction methods are easily customized (for instance, calculating the three wall
areas cited in the example above from a single design element) and are reusable for
multiple projects. Quantities are extracted based on building element types and their
dimensions. Once the quantification is complete, Ryan’s estimator outputs the data from
Innovaya to an Excel spreadsheet for entry into their in-house pricing program.
And with the API link, the quantities are automatically associated with the Revit building,
so they “remember” where they came from. This means that the Innovaya software can
easily detect design changes from the Revit model, which allows the estimator to validate
previous quantities against the new design, and then automatically update those
quantities. As Bates explains, “In the past, our estimators had to manually check design
revisions for cost implications. Now we just re-export the Revit model to Innovaya, and let
the costing software figure out what has changed.”
According to Bates, “We’re very excited about the integration between Revit and
Innovaya. All the data we need for high-quality costing is in the Revit model. With this
integration, our estimators are getting better numbers from the building model, and we can
continue to use each program for its intended purpose: Revit for building design and
Innovaya for construction estimating.”
Linking Design Decisions to Costs via an API
Oculus Inc. (www.oculusinc.com) is a 30-person architectural, strategic facility planning,
interior design, and move management firm with offices in St. Louis, Dallas, and Chicago.
Since their 1994 inception they’ve been committed to meeting voids in the offerings of
traditional firms; helping their clients maximize the value of their investments by linking
architecture to master planning, long range forecasting, space planning, and interior
design. Integral to that commitment is the concept of architectural design linked to cost:
informing their design decision making process.
A longtime Revit user, Oculus immediately recognized BIM’s potential for data-intensive
applications such as facilities management and costing. According to Ron Reim, Oculus
principal and co-founder, “BIM enables us to get better information about our projects, so
we can give better advice to our clients.”
They recently started to use Revit in conjunction with estimating software from U.S. COST
(www.uscost.com), an Atlanta-based company that provides cost management and
project control services and software. Oculus was already quite familiar with U.S. COST’s
estimating software, Success Estimator, as many of their outsourced cost estimates are
developed with it and Oculus routinely (but painstakingly) checks those estimates against
their design model – verifying the estimate for their client. So they were closely tracking
the API integration between Revit and Success Estimator (the commercial product is
called Success Design Exchange), looking forward to replacing those manual checks with
programmatic ones. Once the API link was complete they sent an architect, with a
background in specifications and costing, to a U.S. COST training class and they’ve
recently begun using Success Estimator and Design Exchange themselves.