On December 14, 2023, the Shanghai Municipal Commission of Housing and Urban-Rural Development issued a document stating that “starting from February 1, 2024, in
the Shanghai Municipal Approval Management System for Engineering Construction Projects (abbreviated as the ‘Municipal Engineering Approval System’),
an intelligent assisted review subsystem based on Building Information Modeling (abbreviated as ‘BIM models’) technology will be launched to further improve the efficiency of construction drawing review and the quality of survey and design.” Prior to this, Xiongan, Nanjing, Guangzhou, Shenzhen and other regions had already carried out BIM-assisted drawing review.
Although the specific functions and workflows of BIM-assisted construction drawing review software vary from place to place, the goal is always to improve the efficiency of construction drawing review and the quality of design. After three or four years of exploration, this work has so far, overall, fallen far short of expectations in terms of actual results. In my view, several key factors still need to be clarified before this work can deliver real results.
I. What Conditions Must a Reviewed Model Meet — At the Current Stage, Only BIM Models Consistent with the Drawings Yield Meaningful Review Results
Drawings, models, texts, and tables are different carriers of engineering project data. Each has its own strengths and weaknesses in describing different types of project data; the data they contain partly overlaps and partly is unique to each carrier. As to exactly which project data each carrier holds, this is not necessarily identical from one project to another. In any case, however, the same piece of data expressed by different carriers must be identical or unique; otherwise, one has to verify which is the correct data.In design deliverables, before BIM models existed, drawings, texts, and tables were like this; and once BIM models arrived, the same remained true.
The advantage of BIM models as carriers of project data is that the data is more structured and more visualized than in drawings. In theory, reviewing a model with software can achieve higher efficiency, broader scope, and greater depth in reviewing design deliverables than reviewing drawings. Of course, the first prerequisite is that the review software is sufficiently powerful in function and performance, and the second is that the BIM model being reviewed describes the project data completely and correctly enough. During the period when drawings are the statutory deliverable but models are not yet, the most basic requirement is that the project data carried by the BIM model must be consistent with the corresponding data in the engineering drawings — that is, what is commonly called drawing-model consistency.
A fairly common phenomenon in current BIM-assisted construction drawing review is that the model review identifies a problem in the design deliverables, but upon checking, the drawings turn out not to have that problem; the real issue is that the model and the drawings express the project design deliverables inconsistently, rendering the model review results meaningless. Therefore, only with BIM models that are consistent with the drawings, together with model review software that meets functional and performance standards, will the results of BIM-assisted construction drawing review deliver real value.
II. Who Is the Primary User of BIM-Assisted Construction Drawing Review Software — Quality Is Produced, Not Inspected Into Being
The mechanisms currently adopted in regions piloting BIM-assisted construction drawing review all treat industry regulatory bodies such as construction drawing review agencies as the primary users of the BIM-assisted review software. These bodies use the software as an auxiliary tool for construction drawing review, and reviewers form their review conclusions by taking into account the problems identified by the BIM review software.
Because the quality of the BIM models delivered by designers is still generally low and the functions of BIM review software are still fairly rudimentary, BIM-assisted construction drawing review can so far play only a limited role. As the quality of BIM models and the capabilities of BIM review software continue to improve, when the results of BIM-assisted review can truly deliver real value, will the current model — with construction drawing review agencies as the primary users of the software — still be a reasonable one? This is a question that warrants in-depth discussion.
First, the purpose of industry regulatory steps such as construction drawing review should be to ensure that the construction drawings have no (major) problems, not to find problems in them. Quality management holds a basic principle — “product quality is produced, not inspected into being.” The producers of design deliverables such as drawings and models are the design firms. BIM-assisted construction drawing review software can help detect problems in drawings and models, but the people most effective at finding and resolving problems in design deliverables are the designers themselves. From this perspective, designers should be the primary users of BIM-assisted construction drawing review software.
Second, after a review agency uses BIM-assisted construction drawing review software to identify problems in the design deliverables, the deliverables still have to be returned to the designers for adjustment and revision. Compared with designers using the review software directly, having the review agency act as the primary user of the software is clearly at a disadvantage in terms of project advancement efficiency.
Therefore, having design firms and designers serve as the primary users of BIM-assisted construction drawing review software would seem to be a more reasonable approach.
III. What Should Design Regulatory Bodies Do Once BIM Review Results Are Generally Reliable and Usable — Evaluating the Software’s Functions and Performance, and Auditing Its False Findings and Blind Spots
In the future, after a period of pilot and demonstration exploration, once the review results of BIM-assisted construction drawing review software are generally reliable and usable, will design regulatory bodies and functions such as construction drawing review still be needed? And at that point, what work should design regulatory bodies such as construction drawing review agencies be doing?The answer is yes, and the reasons are straightforward and clear.
First, different BIM construction drawing review software products have their own characteristics and limitations, and different versions of the same review software also vary in function and performance. These circumstances cannot rely entirely on the software vendor’s materials; they require testing across a certain number and range of project types. If this work were left to design firms or designers to do on their own, on the one hand they might not have the requisite capability, and on the other it would waste a great deal of social resources on duplicated effort.
Second, whether review software is in its early stages of development now or gradually matures in the future, two problems will persist. One is that software can detect only some, not all, of the problems in design deliverables. The other is that all software makes mistakes; none is error-free on every issue. With regard to the software’s blind spots and false findings, industry regulatory bodies can and should act as a third-party check, providing an additional layer of safety for the reliability of design deliverables.
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