October 25, 2007
In this blog, which will often be produced while being airborne, I will write about the new approach to estimating that we at Vico have been practicing for about 3 years now. It’s about a technology that has been around for much longer but has become more and more popular with the increasing adoption of Building Information Modeling. This blog is about Model Based Estimating.
One of the goals of this blog is to become a platform for people who are interested in or practice model based estimating. If you’d like to share your experiences with and knowledge of the concept, feel free to send an e-mail to "email@example.com”
As a start, I want to stretch the term “Model Based Estimating”. When talking about Model Based Estimating, it is automatically assumed that it involves the use of 3D geometric building models. Although 3D building models do indeed provide great input for estimates with their ability for automated, accurate quantity take-off, model based estimates can also be based on more abstract, numerical, models (which is often referred to as “key figures”, defined in the conceptual phase of a project).
I will use the term “model” with the description that can be found in most dictionaries: “a hypothetical description of a complex entity or process”. In construction, we create such descriptions on a day-to-day basis: making abstract representations helps us to make decisions on complex situations, like the estimated cost or the budget of a project.
Both types of models (the geometric building model and the numerical model consisting of project characteristics), or also combinations of both, give estimators more decision making power. By deploying the concept, you can actually “model your estimate” by developing alternatives using models to define variations. Analyzing alternatives is easier with models because of their flexible nature; going through iterations makes it easier to decide on the best solution.
Over the past 6 years, I have been working with the concept of model based estimating. I started using the technology as an engineer at the preconstruction engineering department of a construction company and after that, I continued as member of the Graphisoft – now Vico – “Virtual Construction” team. During this timeframe, I have been involved in numerous projects, a lot of them so called “pilot projects”, in which model based estimating was explored. The projects I worked on were projects, in which model based estimating has been applied vary from projects in the conceptual phase, to projects in bid phase.
The amount of available information and the variation in this information throughout the stages of design to pre-construction differs significantly. However, for all phases, the same rule for successful deployment applies: define what your goal is before you start to create your model. Like in math: write down the problem statement and subsequently define the constraints for the model that will help you to solve it.
We also offer a step-by-step guide to our 5D virtual construction workflow with video tutorials. These videos are just 2-5 minutes in length, but illustrate how to use a particular piece of functionality. You can access the video library index and view just what you need, or download the complete set of training videos.