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Construction cost estimate

Construction Cost Estimate

How to limit errors and speed up the construction cost estimate process with the help of Artificial Intelligence (AI)

How often do you find yourself presenting the project to the client and hearing them ask, ‘Yes, but how much will it cost me?’ Estimating construction costs is crucial from the early stages of project presentation as it allows the client to plan interventions according to the available budget.

Let’s explore the fastest and simplest way to estimate construction costs for a project without making evaluation errors, thanks to a 5D BIM software.

Construction Cost Estimate

Construction cost estimation is a significant process in the construction sector, involving the assessment of costs associated with a construction project’s realization. This estimation provides a financial estimate of what it will take to successfully execute a project.

The construction cost comprises the sum of the following productive factors:

  • Materials;
  • Labor;
  • Rentals and transportation.

In the preliminary phase, estimating construction costs with a simplified comparative procedure might suffice. This method involves roughly calculating expenses based on parametric comparison with similar constructions. Once the project’s pre-feasibility phase is surpassed, it’s advisable to detail the cost estimate and calculate construction costs analytically.

This method involves breaking down the process into tasks and then summing the amounts resulting from the product of the quantities of each task by its respective unit price. The process unfolds in the following phases:

  • Classification, where an itemized list of work types (WBS) is compiled;
  • Measurement, where quantities are estimated, and a cost estimate is performed;
  • Estimation of unit prices, usually relying on regional price lists identifying the unit costs of each work type;
  • Construction cost estimation, where the unit price is multiplied by the quantities, resulting in a construction bill of quantities.

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Automating Construction Cost Estimating from the 3D Model with AI

Currently, there’s a faster way to estimate construction costs. The procedure and phases to follow remain similar to those previously described, but certain automations lead to a more accurate outcome in significantly reduced time frames. Simply utilize a 5D BIM software that establishes intelligent connections between the 3D digital model (defining the building’s geometry) and the information concerning the costs of executing the work itself. The result is a comprehensive 5-dimensional information model (5D), inclusive of attributes necessary to estimate the project’s overall cost.

A 5D BIM software should enable you to:

  • Link each object in the model to a relevant price list item;
  • Automatically get the quantity take off for all the entities of the project;
  • Real-time updating of the quantity take off with every model modification;
  • Print, export, and rework the automatically obtained bill of quantities.
5D BIM and automatic metric calculation

5D BIM and automatic metric calculation

With a BIM model, cost estimating can occur automatically by associating the prices of each work type or supply directly with the parametric objects of the 3D geometric model. Besides being a faster and more streamlined process for the designer (cost manager), this method allows full control over the operations to be performed and reduces the risk of errors and discrepancies. By associating prices (selected from a reference price list) directly with the model’s objects, it’s possible to obtain an always-updated cost estimates automatically with every modification made to the project.

What does this mean? It means that by changing the size of a window, the quantity and consequently the cost of that specific task are automatically updated. Thanks to this data, designers can develop accurate estimates based on a reliable source of federated information and analyze different proposed project scenarios in real-time.

Performing a construction cost estimating with BIM 5D software is much simpler and allows obtaining outputs quickly and error-free, thanks to artificial intelligence.
The process involves following these steps:

  • Choose the item from the reference price list directly.
  • Select the entities to be estimated from the 3D model, leveraging the software’s automation.
  • Choose the measurement rule for the identified entities.

What’s Needed for Automatic Cost Estimating?

To begin with, having the project 3D model in IFC open format and a 5D BIM software is essential.

Obtaining an automatic quantity take off directly from the IFC model isn’t much different from the traditional method you’ve always followed.

In fact, we could say the approach hasn’t changed at all. You need to open the price list and choose the items to include. What changes is the input of quantities. It is no longer necessary to measure manually to input quantities; instead, you simpy select two entities in the model with similar characteristics to be estimated, and the software automatically identifies all the entities in the model with such characteristics. You can even adjust properties of various entities, select those with a certain thickness, or act based on the classification attributed to each entity in the model.

The selected entities are highlighted in green, providing a visual reference for the entities to estimate. This significantly reduces the chance of errors.

Once the entities are selected, there’s no need to input measurements since they are already known in a BIM model. For example, you don’t have to manually measure the length of walls to input; the software automatically calculates it. You only need to choose appropriate measurement rules for the various elements to estimate. For instance, if you’re inputting partition walls, which are estimated per square meter, you select length and height. The software automatically calculates the quantities and, naturally, the total amounts for the selected entities.

For further insights, you can watch the video demonstrating how to work with the software.

But what happens if you modify the project?

As often happens, once the estimate is complete, there might be new changes to apply to the project. For instance, modifying the window dimensions, a different internal layout of spaces, etc. These choices would effectively require updating both the 3D model and the just-concluded cost estimating.

And here lies the true advantage of 5D BIM.

If the 3D model changes, the quantity take off, which is dynamically linked to the 3D model, automatically updates in real-time. This prevents errors and saves a lot of time. Moreover, having the ability to directly view the entities and their associated items helps control the cost estimating. You can select the price list item and see which entities are associated with it and vice versa.

Creating New Quantity Take Off Automatically with Standard Templates and AI

The AI Estimating software revolutionizes the process of creating  in the BIM environment.

Users have the ability to generate quantity take off automatically for any project, starting from a previously developed estimated model. This functionality is particularly useful for those frequently dealing with similar cost estimating. Once a cost estimate is created, the software allows saving it as a model and reusing it in other projects, eliminating the need to select specific reference price lists.

Measurement rules, combining entities, tasks, and measurements created for one project, can be saved as a single model or as a template (a set of multiple models), and then reused in any other similar project. Users can select one or more models from their archive, apply them to the current project, and automatically obtain quantity take offs for entities meeting the criteria of the selected models. This approach not only simplifies the computation process but also enhances efficiency and consistency across different projects.

For further insights, also read “5D BIM: The 5 Advantages of the Fifth Dimension of BIM