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A CASE STUDY ON CONSTRUCTING 3D/4D BIM MODELS FROM 2D DRAWINGS AND PAPER-BASED DOCUMENTS USING A SCHOOL
BUILDING PROJECT
S. L. FAN1, S. C. KANG
2, S. H. HSIEH
3, Y. H. CHEN
4, C. H. Wu
5, J. R. JUANG
6
1 Assistant Professor, Tamkang University, Taipei, Taiwan
2 Assistant Professor, Taiwan University, Taipei, Taiwan
3 Professor, National Taiwan University, Taipei, Taiwan
4 Graduate student, National Taiwan University, Taipei, Taiwan 5 Undergraduate student, Tamkang University, Taipei, Taiwan
6 Undergraduate student, National Taiwan University, Taipei, Taiwan
Correspond to Prof. S.L. Fan ([email protected] )
ABSTRACT: Research efforts have demonstrated that building information modeling (BIM)
approaches hold significant potential for the construction industry. However, even though the
advantages are generally acknowledged, they are far from becoming standard practice. This research
presents a case study on constructing 3D/4D BIM models from 2D drawings and paper-based
documents using a typical nine-floor school research building. A 3D model was created from existing
2D drawings using BIM software and a construction schedule was re-constructed from existing
paper-based schedule documents to include the durations of and the relationships between activities.
The data of both applications were transposed separately onto a 4D simulation package. Reported are
the time taken and problems encountered in constructing the 3D/4D BIM model, and the approaches
employed to solve the problems. Our results show that 230 labor-hours were needed for the
construction of a 4163-element BIM model of the building (inclusive of the time for personnel
training). The results provide industry practitioners with some useful empirical data and documented
experiences for when applying BIM technologies to building projects.
Keywords: BIM, 4D simulation, Building construction, Case study
1. Introduction
Building information modeling (BIM) and 4D modeling have recently attained widespread attention in
the architectural, engineering and construction (AEC) industries[1,2,5]. Research efforts demonstrate
the BIM and 4D approaches provide a faster and more effective way of communicating information
between interested project parties and a better design which enables improved and innovative
solutions as well as many other benefits[1,3,6,7]. Numerous case studies have also been conducted
showing that use of BIM results in time and cost savings[1,2,3,8] by elimination of unbudgeted change
and unplanned change orders, cost estimation accuracy and time reduction, clash detections and
elimination of rework[1,2,3,8]. Some research adopts GIS and web-based technology [4,10] providing
an alternative to the existing 4D tools whereas other researches present solutions for creating time
schedules and 4D simulations based on data stored in a building model[7,9]. Nevertheless, current
planning processes in the construction industry are still mainly based on 2D drawings[1]. For a
construction managerr, with 2D drawings provided, redesigning a project using 3D modeling software
might be too large a jump. Therefore to construct 3D/4D BIM models from 2D drawings would be a
more practical choice. However with the time needed to construct 3D/4D BIM models from 2D
drawings being the main concern, constructors still struggle with applying the 3D/4D model
technology on their specific projects.
This research takes a nine-floor building as a case study to quantify the labor and time needed for
constructing 3D/4D BIM models from 2D drawings and paper-based documents. It provides
contractors useful empirical data for applying BIM technologies in building projects.
2. Case Project
The case study focuses on a typical research building of National Taiwan University. The project is a
precast concrete construction RC building possessing a seismic isolation system at the mid-story. This
building consists of an underground parking basement and nine floors with a total height of
approximately 41.4 m and a total floor area of 9686.44 m². The construction period was 6 months.
Figure 1 shows the project visualization and a photo taken on-site.
Figure 1 Project visualization (left) and a photo taken on-site (right)
There are two primary workflows involved:
2.1 2D to 3D
A 3D model was created from existing 2D drawings using standard BIM software called Revit
Architecture. The detailed workflows included setting up grid and level, and inputting each floor plan
to each level.
2.2 3D to 4D
A construction schedule was created from a paper-based schedule and provides durations of activities
and the relationships between activities using MS-Project without any information sharing from the
3D model. The data of the schedule and the 3D model were exported separately to a 4D simulation
package called Autodesk NavisWorks. This was followed by the linking of 3D objects to the activities
in the time schedule automatically and manually.
The aforementioned workflows were conducted by a graduate student and an undergraduate student of
the Computer-Aided Engineering Group at National Taiwan University and an undergraduate studying
construction management at Tamkang University in Taiwan. Each student was familiar with the
Windows operating system, yet all were beginners of BIM software.
3. Results
3.1 Errors Found in the 2D to 3D process
During the process of transposing 2D information into a 3D model, two types of errors were found:
1. Referencing Errors
Before transposing 2D information into the 3D model, a referencing error was found. Each floor plan
in the project consists of 3 files. The first file is a standard drawing frame for each drawing which
shows the basic information of the project. The second file is the structural drawing for that floor,
named S201 thru S2011 to refer to the structure for the basement, 1st floor, the floor in between 1st
floor and isolation floor, isolation floor, 2F and the floors above. The third file is a drawing for steel
ladders, elevators and curtain walls for that floor, named as Basement, 1F, 1MF (refers the floor in
between), isolation floor, 2F and the following floors.
In this project, the isolation floor which was not named is named as 2F and the original 2F is renamed
as 3F, and so on after the design drawing has been completed. The name of the 3rd files and the title in
each structure drawing were revised accordingly. However it results in an error in each floor plan
which linked these 3 files automatically using AutoCAD. For example, as shown in Table 1 and Figure
2, 2F floor plan links the file named “S204”(the structure drawing of isolation floor) with the file
named “Isolation Floor”( a file which doesn’t exist after revision of file names), and 3F floor plan
links the 2nd
file named “S205”(the structural drawing of 3F) with the file named “2F”(the drawing for
the elevators, curtain walls and steel ladders of isolation floor). Therefore before noticing this error,
many conflicts were found in each floor plan because of this miss link of files. The fourth column of
Table 1 shows the correct link which has been revised manually by the research team after realizing
this error.
Table 1 Referencing Error and the Revision
Link Before Revision After Revision
2F Floor Plan 1st File Drawing Frame Drawing Frame
2nd File S204 S204
3rd File Isolation Floor (File not found!) 2F
3F Floor Plan 1st File Drawing Frame Drawing Frame
2nd File S205 S205
3rd File 2F 3F
Figure 2 Drawing of 2F floor plan before and after revision
2. Drawings Conflicts
When incorporating 2D drawings into the 3D models, many drawing conflicts were found. As shown
in the left-hand image in Figure 3, the steel staircase which should be above the steel beam is
displayed under the steel beam; therefore a revision was necessary. The right-hand image shows the
revised drawing.
Figure 3 Drawing before and after revision
3.2 Problems encountered in the 3D to 4D process
Since there is no information sharing between the schedule and the 3D model, the names of the 157
activities in the time schedule of MS-Project do not match with the names of the 4163 elements in the
3D model of Revit. Therefore, after both the elements of 3D model and the activities of the schedule
are exported to Navisworks, there exists no automatically created link between them. Due to the large
number of elements in the 3D model, linking them manually to activities would be excessively
time-consuming. Therefore the team grouped the elements into 74 stages in Revit according the
schedule, and revised both files to make the name of each stage the same as the name of each activity.
The files were then exported to Navisworks. However another problem was encountered. There were
some activities in the schedule such temporary facilities and excavation for which matching elements
had not been built in the 3D model. The solution to this problem by the research team was to show the
location of the activity using colors and text to explain the task in the 3D model.
3.3 Time Spent
As shown in Tables 2 and 3, to construct a 4163-element BIM model and incorporate it with a
157-activity schedule required 230 labor-hours. This time included: 10 hours of Revit and 8 hours of
Navisworks training for the 3 students, 86 labor hours to transpose 2D information into the 3D model,
and 20 labor hours to establish a the 4D model. Clearly the process of moving from 2D to 3D takes
much more time than the process of moving from 3D to 4D, and customizing or modifying each
element takes about 2 labor hours on average.
Table 2 Details of the 4163-element of BIM model
Elements Quantity Remarks
Roofing Sheet and 1 7 Customized Elements,1
same Rain Awing element is
repetitively used to 161
places
Handrail for parking ramp 1
Parking Ramp 1
Disabled Ramp 3
Rain Awning 1
Ceilings 2 3973 Revit Built- in
elements
Curtain Wall Slabs 348
Curtain Wall Cells 193
Curtain Wall Frames 993
Handrails without Cast Panel 53
Floor Slabs 54
Stairs 25
Walls 1035
Equipments 2
Windows 183
Foundations 2
Columns 301
Frames 277
Beams 22
Joists 166
Girders 253
Line 11
Openings 2
Doors 51
Handrails with Cast Panel 23 1 Modified Built-in element
(adding cast panel to the
built in handrail element) is
repetitively used to 23
places
Total 4163
Table 3 Time taken in transposing 2D drawings to a 4D Model
Stages Workflows Time Taken
(man-hrs)
1. Training Personnel Training 18hrs*3=54 18hrs*3=54
man-hr
2. 2D to 3D
Setting up grid and level 1 2D to 3D
workflow
156man-hrs
Inputting each floor layout to each level 0.5
Building models with Revit built-in elements
(3973 places)
126
Customizing 7 elements
14
Building models with Customized
Elements (167 places )
2
Modifying 1 built-in element 2
Building models with modified built-in
elements (23 places)
3
3. 2D to 3D Error
Correction
External reference error 2
Drawings referencing error 5.5
4. 3D to 4D Exporting 3D model from Revit to
NavisWorks
5 3D to 4D
workflow
20 man-hrs
Generating schedule with given durations of
activities and the relationships between
activities using MS-Project and exporting the
schedule from MS-Project to Navis Work
4
Linking of 3D objects to the activities in the
time schedule automatically and manually
1
5. 3D to 4D
Problem Solution
Establishing Stages in Revit and exporting to
NavisWorks
8
Revise the activity name in MS project 0.5
Linking of 3D objects to the activities in the
time schedule automatically and manually
1.5
Total 230
4. Lessons Learnt
The three main lessons learnt during this study are as follows.
4.1 Systematical Naming of Drawing Files
It is recommended that participants adopt an identical and systematical naming convention for
drawing files. One method would be to have all files named using 5 digits, where the first digit refers
to the type of the drawing, and other four digits refer to the specific location ID. This is preferable over
naming the drawings according to the locations, in order to avoid the referencing errors that occurred
in the studied case.
4.2 Information Sharing
As shown in 3.2, without information sharing, the names of the elements and the names of activities in
the schedule will not be identical. Therefore it is recommended that the personnel establishing the
construction of the 3D model should consult the scheduler before building the model, and set up an
identical rule for naming activities/stages, so that when incorporate the 3D model and the schedule
into a 4D software package, the automatic linking function provided by the 4D software can function.
4.3 BIM Element Library
As shown in 3.3, each modified or customized element takes on average two hours of labor time. This
is very time-consuming when compared with the two minutes for each built-in element. Therefore it is
recommended that the developers store the elements built in each project so that they can be shared
between projects. Such a BIM-element library would reduce the time for building the customized
elements.
5. Conclusions
This research presents a case study on constructing 3D/4D BIM models from 2D drawings and
paper-based documents using a typical nine-floor building. This study reported the time taken and the
problems encountered in constructing the 3D/4D BIM model, and the approaches employed to solve
the problems. Two hundred and thirty hours of labor were needed to construct a 4163-element BIM
model and incorporate it with a 157-activity schedule for the nine-story building studied (including the
time for personnel training). The results provide contractors some useful empirical data for estimating
the time needed to construct a 3D/4D model from 2D drawings and paper-based documents; it also
provides constructors with some documented experiences learnt from this case study.
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