# Productivity Analysis of Documentation Based on 3D Model in Plant Facility Construction Project
## 4 Productivity Analysis of 3D-Model-Based Documentation
### Productivity Analysis of Assembly Drawing Extraction
#### 4.2.1 Detailed Task Comparison in Documentation
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & & & & & **(Unit: min/ldrawing)** \\ \hline
**Types of** & **No. of** & **2D-Drawing-Based** & **Working** & **3D-Model-Based** & **Working** & **Productivity** \\
**Assembly** & **Assembly** & **Decumentation** & **Time** & **Documentation** & **Time** & **Improvement Ratio (\%)** \\
**Drawings** & **Drawings** & & & & **(Min)** & **(Min)** \\ \hline Column & 23 & 60 & 1380 (8.17\%) & 40 & 920 (10.65\%) & 33.33 \\
**Girder** & 73 & 55 & 4015 (23.78\%) & 40 & 2920 (33.82\%) & 27.27 \\
**Beam** & 380 & 25 & 9500 (56.26\%) & 10 & 3800 (44.01\%) & 60.00 \\
**Brace/Post** & 199 & 10 & 1990 (11.79\%) & 5 & 995 (11.52\%) & 50.00 \\
**Total** & 675 & Mean 25 & 16.885 & Mean 13 & 8635 & 100.00 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Productivity comparison of two documentation methods—assembly drawingand BRACE/POST was 10 min and 5 min, respectively, improving 60.00% and 50.00% productivity compared to 2D-drawing-based documentation method. The assembly drawing documentation time for BEAM and Girder was 3800 min and 2920 min, respectively, accounting for 44.01% and 33.82% of total work time. 2D Documentation Review vs. 3D Modeling  
The 2D-drawing-based documentation approach puts a lot of work into documentation review to review the integrity of individual drawings. In contrast, the 3D-model-based documentation approach enables engineers to coordinate and collaborate on the 3D modeling task of creating a master 3D model. In this study, the time spent on each task is analyzed in Table 5. According to the analysis results, the time spent by the engineer to review the integrity of the drawings was equally investigated. This means that it is difficult to guarantee 100% of the integrity of the drawing through the 2D-drawing-based documentation method even if the quality improvement effort of cross-reviewing each type of drawing is repeatedly performed. On the other hand, in the 3D modeling based documentation method, 3D modeling work time for Module A was 10 days, which is much higher than 3D modeling work time for Modules B-D. This is because it takes a lot of time to build libraries that are commonly used in the project when 3D modeling work for the first module, and to establish the standards for various types of information included in the drawings and templates according to the types of drawings. When the document is based on the 3D model, the integrity of the drawing and calculation information is secured according to the integrity of the 3D model. In addition, it can proactively cope with revisions to design and engineering that occur after the creation of primary fabrication documents. In other words, when the 3D model is modified, the view is updated due to the parametric characteristics provided by BIM software, and the fabrication documents including the view is automatically updated. Documenting method using 3D model can save work time and reduce human error. Incidentally, the accuracy and efficiency of the production can be improved by generating the file input to the CNC machine. In the installation and construction process, various 3D model views can support scheduling to make the process easier to understand.