Estimating with BIM

Kevin R. Miller
BYU Construction Management
Estimating today
 When was the last time you estimate a set of plans that
were 100%
 How long did it take you to do the takeoffs?
 Who bears the risk today if the plans aren’t complete?
 How do you cope with plans that aren’t complete?
 Hard Bid
 Negotiated, Design-Build
Benefits of Takeoff Process
(Traditional Plans)
 Become familiar with the project
 Find problem areas and identify risk and constructability
 Value engineering
Down side of Takeoff
(Traditional Plans)
 Time consuming (Detailed Estimates)
 May miss something
 Transferring quantities from takeoff sheets to Estimating
software tedious and non productive
What do we want from the Model?
 Accurate quantities
 Less takeoff time
 Better visualization of project
 Subs to understand the project and their scopes.
 Competitive edge
 Clash detection
 Visual means to communicate to clients
General Sales Pitch
 Push the button.
 Costs are generated.
 The 4/5 D model is generated.
 All the work is done.
 Looks good, sales software.
 Not necessarily doable without a LOT of extra work.
Model World Today
 Not the magical pushing a button and the estimate is done.
 No such thing as a 100% Model
 Costs come from your estimating database not Means or
some other source
 The liability that exists with 2D drawings exist with 3D
 With BIM – Risk shouldn’t change or shift
Models cont
 Takeoffs consume less time
 More time verifying what is modeled is constructable
 Better understanding of design intent
Estimating from the Model or Not?
 Do I really want to work from the Model?
 No, I want static drawings that don’t change so there is an
accurate history of the costs for the project
 No, I don’t want the potential to change the drawings
because I’m and estimator, not a modeler
 No, the file size of the model would really slow me and my
computer down.
 DWF file (a read-only copy of the model) addresses the
above concerns
What can we really get from the
 Counts
 Lengths
 Areas
 I have concerns about the wall areas and volumes
Use Length * Height for areas
Use Length * Height * Width for volumes
 When in doubt, check the quantity calculation.
Timberline/MC2 Opportunities
 QTO integrates seamlessly into Timberline.
 QTO integrates with MC2.
 Use Timberline/MC2 for complete estimates instead of
jumping to Excel (Conceptual/Budget not Bid day)
 Cleanup and optimize the estimating DB
 Too much legacy junk in estimating DB’s
 Every item in the DB should have a formula in order to link
 QTO integrates better with Timberline than Timberline
What is needed to Estimate
From the Model
 3D model
 2D modeled sheets
 Allows you to perform takeoff for the things not modeled.
 DWF file format
 May use PDF, jpg etc files but they will not link to the 3D

similar documents