We are currently exploring how to directly generate costs within BIM and how to analyze dynamic cost change curves following scheme and design modifications.
The calculation software operates in the following sequence: first, create the model; next, define component properties; then set consumption quotas; proceed to calculation; and finally, obtain the engineering quantity data. It is important to note that defining component quotas is intended for measurement rather than pricing. Our goal now is to enhance this functionality by using these quotas to provide both quantity data and bidding information.
As is widely recognized, consumption quotas that align with project characteristics should be linked to the component list. The software should support intelligent matching of these quotas. These quotas contain detailed information, including labor, materials, and machinery consumption. Additionally, each quota corresponds uniquely to codes related to personnel and machinery within the pricing database. By multiplying consumption by the engineering quantity, then by the unit consumption price, and further by management fees, profit margins, regulatory fees, and taxes, we arrive at a comprehensive total cost. Dividing this total cost by the engineering quantity yields the overall unit cost.
Costs such as large machinery entry and exit fees, vertical transportation fees, external scaffolding fees, and other similar expenses must be broken down into individual sub-items. It is crucial to understand that the cost model is neither a design model nor a quantity calculation model, nor is it simply visual pricing software. Instead, it is a BIM-based design that integrates quantity calculation and pricing modules, featuring high integration and strong data correlation. This eliminates the need for data export/import or repetitive input of inventory quotas.
More importantly, the data is logically interconnected and can be updated in real time. We have incorporated a cost module into the BIM model that links directly with the pricing database. When calculating quantities, component consumption data is automatically generated and matched with the pricing information. Management fees, profits, regulatory fees, and taxes can be globally set in the overall parameter settings, removing the need for manual entry for each component. This approach ensures components carry not only quantitative data but also valuable cost information. Furthermore, the quantity and price of components adjust naturally in response to changes in cross-section or height.
Currently, we do not factor in the effects of changes in construction plans, techniques, or different contracting methods on cost, though it is important to acknowledge that these factors can significantly impact cost sensitivity.
We can also classify, subdivide, and summarize project progress based on various criteria, which is particularly beneficial for cost analysis before and after model changes. This capability allows for easy generation of cost fluctuation curves over time. Another advantage is the extraction of costs at different project stages. Whether during the scheme phase, expansion phase, construction drawing phase, bidding phase, or professional deepening drawing phase, costs can be derived from the same model. Costs evolve with the increasing detail of the model, eliminating the need to separately handle project estimates, design budget estimates, bidding control prices, bidding prices, construction drawing budgets, change settlements, and completion settlements. This deepening and refinement significantly enhance the accuracy and reliability of cost estimation.
In the past, estimates and budgets were often seen as formalities with limited practical value, failing to achieve effective cost control during design due to their rough nature and minimal reference value.
The BIM-based cost model allows for component-level granularity. For example, the cost of a specific beam can be queried directly. If that beam needs to be dismantled and rebuilt, the required cost is immediately clear. Traditional cost documents typically break down costs by sub-items, making it difficult to retrieve the cost of an individual component like a beam.
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