| | No. | Content | Conventional method | BIM-3D laser scanning |
| | 1 | Data collection time-point cloud data processing time | The manual measuring process is time-consuming and error-prone. The lack of accurate and up-to-date as-built information often occurs because of limitations in working time and budget for manual data collection. Only considering the time to calculate the exact volume of masonry walls, lintels, or correct pillars. The time required includes (i) at least 1 day to measure current volumes and (ii) approximately 3–4 hours to input and calculate the volume. Furthermore, some of the unfinished construction works have indeterminate shapes, which makes it necessary to make a determination of the execution volume, which consumes more time. | All efforts of the 3D laser scanning are concerned with building model reconstruction and not with just measuring progress; the laser reflection collects all spatial data. For a project with many completed items at the same time, such as ceiling construction, wall painting, and tiling, it is possible to distinguish and calculate the entire workload of the project with the laser scan and BIM. In the testing project for this research, the authors set up 18 stations; the total implementation time was about 1 hour and 30 minutes, including the time to place the machine at various locations to collect data. In the point cloud data processing phase, it took 1 hour and 30 minutes to import and merge data and remove unnecessary point cloud data. The total time to build a BIM model from point cloud data and export the volumes was about 4 hours. If a projector needs to calculate the volume of a ceiling or tile, it only takes about 1–2 more hours to build the model from the point cloud model. The entire application process took nearly 8 hours (equivalent to about one working day) to produce the actual BIM model and export a detailed volume schedule. |
| | 2 | Accuracy | In this research, the testing project has a relatively simple shape of walls or concrete elements. However, the volume calculated that agrees with the conventional method is lower, approximately 7.16% (for masonry walls) and around 1.93% (for lintel) compared to the volume exported from the BIM-3D laser scanning model. | Laser scanning technology implies that the collected results can be very accurate with a high level of detail. The BIM model is built with nearly 99% precision. |
| | 3 | Cost | Volume determination mistakes can result in project delays, expenses for consultants, and handicapping the managers’ ability to monitor schedule, cost, and other performance indicators. Based only on the temporary price for a consultant, counting on the wall volume, there is a 7.16% increase in the cost of wall construction tasks compared to the BIM-laser scanning method. This difference originated from volume determination mistakes caused by the conventional method. | The cost for BIM and 3D laser scanning implementation is relatively high (∼70.000 USD for RTC360). Not only is the investment in equipment and software expensive, but also it requires a high level of skill. However, implementation takes less time and manpower, and the resulting model can be used throughout the life of the project (such as updating the actual conditions of the project compared to the design condition, making accurate as-built drawings, providing documents for operation, and maintenance of the project). As a result, the overall costs become more reasonable. |
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