BIM Cost Estimating System Subjective Quantity Tracking
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Solution Overview
Problem
Existing BIM-based estimating solutions fail to track and make explicit subjective quantities and cost allowances, which are crucial for accurate cost estimation in complex construction projects, leading to a lack of trust and adoption among estimators.
Innovation Solution
A system that integrates model-based estimating by using a formula where the total cost from the model, subjective costs, and master estimate are balanced, allowing for the tracking and updating of cost driver groups and subjective quantities, ensuring the reliability and maturity of the cost model.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional 2D drawing-based quantity takeoff is used, then the process is simple and familiar, but it becomes error-prone and inefficient when dealing with complex designs
Solution Approach 1:
The patent replaces manual 2D drawing-based quantity takeoff with automated BIM-based extraction. The system automatically extracts quantities from 3D BIM models using programming scripts, eliminating manual measurement errors and significantly improving both productivity and precision for complex designs.
Solution Approach 2:
The patent transitions from two-dimensional drawing-based estimation to three-dimensional model-based estimation. By extracting quantities from 3D BIM models, the system captures spatial complexity and geometric relationships that are lost in 2D representations, thereby improving measurement precision for complex geometries.
2Extent of automation
If existing BIM-based estimating solutions are used, then quantity extraction is automated, but subjective quantities and cost allowances are not tracked or made explicit
Solution Approach 1:
The patent segments cost estimation into distinct categories: automated BIM-based quantities, subjective quantities requiring estimator judgment, and cost allowances. This segmentation allows each component to be tracked and managed separately, ensuring that subjective elements are not lost in the automation process.
Solution Approach 2:
The patent introduces a database as an intermediary component that stores and tracks both automated BIM quantities and subjective quantities. This database acts as a mediator between automated extraction processes and human estimator judgment, ensuring that all quantity information is preserved, tracked, and made explicit throughout the estimation process.
3Reliability
If estimators rely on personal interaction and detailed manual estimation, then they understand their estimates well and can defend them, but the process becomes time-consuming and less scalable
Solution Approach 1:
The patent implements feedback mechanisms where the system automatically extracts quantities from BIM models, compares them against cost data, and provides real-time cost estimates. This automated feedback loop reduces the time estimators need to manually verify calculations while maintaining confidence in the estimates through transparent, data-driven results.
Solution Approach 2:
The patent enables the estimation system to serve itself by automatically extracting quantities from BIM models and generating cost estimates without requiring extensive manual intervention. The system performs self-verification through automated data extraction and cross-referencing, reducing estimator workload while maintaining estimate reliability.
Data Source
AI summary
A system and method of model-based estimating comprising: receiving a master estimate, including a plurality of master subitem estimates; generating a model estimate, including a plurality of model subitem estimates; generating a subjectives estimate, including a plurality of subjectives subitem estimates; receiving a model update; determining which of said model subitem estimates and said subjectives subitem estimates is impacted by said model update; determining one or more cost updates to said model subitem estimates and said subjectives subitem estimates; updating at least one of said model subitem estimates and said subjectives subitem estimate, based at least in part upon said step of determining one or more cost updates to said model subitem estimates and said subjectives subitem estimates.