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LOW-COST 4D BIM MODELLING: A COMPARISON BETWEEN FREECAD AND COMMERCIAL SOFTWARE

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Abstract

The paper aims to investigate the potential inherent in a FOSS (Free and Open Source Software) approach for the 4D BIM modelling using Freecad. In order to reach this goal it shows a comparison of Freecad features with those of commercial software, considering the evaluation of the effective application of this Open Source software in the professional environment, and highlighting the progress in the FOSS BIM area, that still represents an unexplored study field if compared to the vast publications related to BIM modelling that occurred in the last two decades. To this end, the study has been carried out on a singular case study, a steel canopy which has been designed for the urban renewal of a public space in Teramo. Despite its size, the canopy required the definition of complex details. Its structural system has addressed the study to compare Freecad with some software dedicated to steel structures or particularly suitable for the modelling of this specific structural typology: Tekla Structures and Sketchup. Starting from a concise historical reconstruction of the FOSS spread, the paper introduces a brief overview of the potential of Freecad in terms of BIM modelling - also proposing an operational modality to facilitate the drawing of BIM elements within the software - and finally reaching to the examination of three simulations which has been carried. This comparison can be useful to establish the current state of development of Freecad in the field of 4D BIM.
LOW-COST 4D BIM MODELLING
A COMPARISON BETWEEN FREECAD AND COMMERCIAL SOFTWARE
D. Di Donato 1*, M. Abita 1
1 DICEAA, Department of Civil, Construction-Architectural and Environmental Engineering
University of L‘Aquila, 67100 L‘Aquila, Italy – (danilo.didonato, matteo.abita)@univaq.it
Commission II
KEY WORDS: 4D BIM Modelling, FOSS, Freecad, ProjectLibre, Steel Structures
ABSTRACT:
The paper aims to investigate the potential inherent in a FOSS (Free and Open Source Software) approach for the 4D BIM modelling
using Freecad. In order to reach this goal it shows a comparison of Freecad features with those of commercial software, considering
the evaluation of the effective application of this Open Source software in the professional environment, and highlighting the
progress in the FOSS BIM area, that still represents an unexplored study field if compared to the vast publications related to BIM
modelling that occurred in the last two decades. To this end, the study has been carried out on a singular case study, a steel canopy
which has been designed for the urban renewal of a public space in Teramo. Despite its size, the canopy required the definition of
complex details. Its structural system has addressed the study to compare Freecad with some software dedicated to steel structures or
particularly suitable for the modelling of this specific structural typology: Tekla Structures and Sketchup. Starting from a concise
historical reconstruction of the FOSS spread, the paper introduces a brief overview of the potential of Freecad in terms of BIM
modelling - also proposing an operational modality to facilitate the drawing of BIM elements within the software - and finally
reaching to the examination of three simulations which has been carried. This comparison can be useful to establish the current state
of development of Freecad in the field of 4D BIM.
* Corresponding author
1. OPEN SOURCE AND DIGITAL REVOLUTION
The paradox of Robinson Crusoe, which Karl Popper adopted
in ―The open society and its enemies‖ to describe the
necessarily public character of science (Popper, 1974), has been
used by Alessandro Frigeri and Gisella Speranza to establish a
comparison between the control of theory at the basis of the
scientific method, grounded on the reproducibility of
experiments, and the IT procedures that govern the creation of
Open Source software (Frigeri & Speranza, 2011).
For the commercial software the source code is not released,
therefore the users (end-users) are restricted to the condition of
simple consumers and they must rely on the correctness of its
operational sequence and the results that it proposes, being
unable both to govern or to control it. They are subjugated by a
technology, scarcely knowable and verifiable, in possession of
few depositories, perched in the isolation of an imaginary turris
eburnea that associate them not only to the Robinson of Karl
Popper, but also to the enigmatic figure of Jorge of Burgos, the
jealous guardian of knowledge enclosed in the labyrinth- library
of ―The name of the rose‖ (Eco, 1980).
The alternative paradigm of the free software, that has born on
the push of the hacker movement, has opposed to the
restrictions imposed by the monopoly of the big IT companies
(Levy, 1984, Himanen, 2001, Wayner 2000, Raymond et al.
2003, Graham 2004, Di Bona & Ockman 2008). Its most well-
known results are the free/libre text editor Gnu Emacs and the
Operating System (OS) Gnu / Linux (Stallmann 2018a, b, Kelty
2008). In particular, this OS, originated by the union of the
GNU operating system and the Linux kernel, represents one of
the several links that the free software movement has
established with the following Open Source movement
(Markoff 2005, Open Source Initiative 2018). Despite the
countless frictions and controversies, fostered over the years by
the charismatic figures that liven up the two parts, in particular
Richard R. Stallman and Eric S. Raymond (Stallman et al. 2002,
Raymond 1998), it is sometimes difficult to identify a clear
dividing line between them.
In any case, Open Source owes a great tribute to the free
software movement for the introduction of the ―copyleft‖ also
created by Stallman and the Free Software Foundation founded
by him - an innovative way of distributing software and
documents, in order to ―copy the program, modify the program,
and distribute modified versions - but not permission to add
restrictions of their own‖ (Stallmann 2018c, Free Software
Foundation 2018). The copyleft finds its substantial and legal
translation in the GNU General Public License or GPL, the
license that will become the foundation for the others that will
be used over the years for the release of Open Source software
and documents (Stallman et al. 2002).
Another fundamental step is the innovation introduced by Linus
Torvalds for the "subversive" project of the Linux kernel,
released under the GPL license; the Swedish IT technician has
invented a development methodology that has been certainly
original and which hasn‘t been organized on a rigid hierarchical
control of software packages, but on a horizontal sharing,
extended to a very large community, involved in the realization
of substantial parts of the software. Raymond has recognized
the experimental value of the Torvalds method, and he has
enhanced its original character and pervasive effectiveness,
The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XLII-2/W17, 2019
6th International Workshop LowCost 3D – Sensors, Algorithms, Applications, 2–3 December 2019, Strasbourg, France
This contribution has been peer-reviewed.
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107
resorting to the contrast between established and traditional
practices of software development, the commercial ones in
particular, similar to the construction of large cathedrals, and
the innovative method of Torvalds, where the control of chaos
and the widespread participation of developers have seemed to
recall the image of a bazaar (Raymond 1999).
The "Unintended Consequences" produced by the introduction
of the GNU GPL and the work methodology proposed by Linus
Torvalds have represented for Manuel Delanda an "institutional
environment" for a new economic system based on the
production and exchange of Open Source software (DeLanda
2001), in order to constitute the foundation of its definitive
affirmation.
Another aspect that has favoured the success of the free
software and the Open Source movements is the sudden spread
of the Internet and the WEB, "a completely new world" (Floridi
1995), "a Pygmalion" which is able to establish and to organize
new virtual communities that can participate and collaborate in
the realization of ambitious shared projects. Therefore the
Internet platform has represented the intangible support for the
constitution of the institutional environment which has been
based on a deep and radical "Digital Revolution", in the
Information and Communication Technology (ICT) sector.
2. THE BIM IN FREECAD
The development model proposed by Torvalds was the driving
force for the definitive affirmation of the Open Source world;
without a doubt the bazaar prototype has been strictly related to
a significant character of the movement, its capillary and
pervasive nature, leading to its many branching that have
interested and still affect the different areas of computer
programming.
However, within an incredibly rich, manifold and stratified
scenario, a field of research almost unexplored and unrelated to
experiences of Open Source software remains the Building
Information Modelling (BIM). In fact its development is due, in
an exclusive form, to big companies of the computer
technology. Some software such as B-Processor (―B-processor‖
n.d.) - a program realised by the Aarus School in collaboration
with the Alexandra institute, still in the pre-alpha version but no
longer developed since 2015 - or xBIM Toolkit (―xBIM
Toolkit,‖ n.d.) - firstly developed in 2007 by prof. Steve
Lockley with the subsequent support of Northumbria University
in 2009 - have proposed useful tools for the implementation of
BIM projects. Another significant initiative is linked to
IfcOpenShell, "a free Open Source IFC geometry engine based
on OpenCascade Technology". The IfcOpenShell libraries and
the OpenCascade Technology represent nowadays an
indispensable aid to numerous computer graphics software, both
commercial and Open Source (―IfcOpenShell,‖ n.d.; ―OPEN
CASCADE,‖ n.d.). Among them Freecad has emerged in recent
years as one of the few valid free alternatives to proprietary
BIM software. This program dated back to January 2001 and its
first developer was Jürgen Riegel, preparing at that time to work
on an Open Source GOM (Graphical Object Modeler) able to
implement Qt multi-platform libraries (Dalheimer, 2002), the
Python programming language (Horstmann, 2013) and Open
CasCADE. Open CasCADE - a 3D CAD / CAM software
development platform (Computer-Aided Design and Computer-
Aided Manufacturing) and CAE (Computer-Aided Engineering)
with an integrated CAD-Kernel - was in origin a commercial
software but its proprietary company, the Matra Division,
decided to abandon its development plan releasing the code as
Open Source. For the software architecture of Freecad Riegel
was inspired by Catia V5 by Dassault, well known in the
architectural field because Frank Gehry studio used it to manage
some of its complex projects (―Gehry, Dassault and IBM Too -
Day,‖ n.d.). Its inventor thus announced the launch of Freecad
on the OpenCascade Forum: "It features some key concepts like
Macro Recording, Workbenches, ability to run as a server and
as a dynamically loadable applications' extension, and it is
designed to be platform independent" (―History - FreeCAD
Documentation,‖ n.d.). Werner Mayer, a Riegel's colleague,
joined his friend in the Freecad development right away. In
2005 Imetric ―donated most of its Mesh Module to FreeCAD
and the Open Source community, and since then they used
FreeCAD as basis for their sensor system software‖. Also in
2005 the developers decided to abandon part of the
OpenCascade framework, preserving only its kernel and
replacing the rest with its own implementation. In 2008 the
Belgian architect Yorick van Havre joined the team. He started
work on the Draft Module, which allowed the drawing of 2d
geometries; he also worked on expanding the FreeCAD
documentation. In the last decade contributions to the
development have become more and more numerous and fields
of interest of the software have extended to new branches,
confirming the multidisciplinary character of Freecad since first
release versions. This aspect has produced a really complex
software architecture which is organized in workbenches
corresponding to different work environments of the program.
In the last few years this generalist feature of the software also
involved the development of a special workbench, specifically
dedicated to BIM and edited by van Havre himself (―BIM
Workbench - FreeCAD Documentation,‖ n.d.). The BIM
workbench was firstly conceived as a simple implementation of
the Arch workbench but later separated. The development of
this BIM module is following typical dynamics of the Open
Source environment: it is based on the principle of sharing
libraries that have been developed in other areas, such as the
IfcOpenShell; it is grounded on the active collaboration of
developers and users' community who test the versions of the
specific workbench - monthly or bimonthly released - and guide
the development program through a constant verification of the
software and a fertile exchange of ideas on possible
improvements and implementations, which are promptly
proposed on the pages of the Freecad user forum specifically
dedicated to the Bim workbench. The current released version
of Freecad is the 0.18; compared to previous versions, the last
has numerous updates including the Qt 5.6.2 and Python 3.6.6
libraries. The implementation of these libraries offers new
opportunities for the software development although it has also
revealed some problems, for example the incorrect functioning
of some macro and complementary workbenches which have
been proposed by developers' community. These critical aspects
are probably due to the closeness with the release of the last
Freecad version; as a consequence some complementary addons
have not been adapted to new libraries yet but this gap is
presumable/desirable that it can be shortly filled.
The state of art concerning studies focusing on Freecad BIM
features is limited and often related to themes not strictly linked
to the 4D BIM Modelling (Falck et al., 2012, Logothetis et al.,
2017a, Logothetis et al., 2017b, Logothetis et al., 2018).
3. THE 4D BIM MODELLING
Time planning is strictly necessary for the successful outcome
of an architectural work. The control of building phases, the
management of companies and workers sequence, represent
fundamental details for a prior organisation, even though time is
often an unpredictable parameter for the building field due to
the delicate combination of location, resources and people
The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XLII-2/W17, 2019
6th International Workshop LowCost 3D – Sensors, Algorithms, Applications, 2–3 December 2019, Strasbourg, France
This contribution has been peer-reviewed.
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108
involved in the construction process (Srdić and Šelih, 2015).
The term 4D means the addition of time specification to a 3D
model widening the interactive environment with another extra
dimension (x, y, z, t), an experimentation that was firstly tried
with CAD facilities. The tool CIFE 4D-CAD, developed at
Stanford University in the 1990s (McKinney et al., 1996), was
one of the first attempt to link CAD elements to time schedules
and CPM (Critical Path Method) diagrams, but apart the
advantages, many deficiencies were gradually highlighted in the
4D-CAD applications. Tools like 4D SpaceGen, 4D-GCPSU
(Graphical Construction Planning and Site Utilization), 4D-
MCPRU (Management for Construction Planning and Resource
Utilization), all developed in the early 2000s, permitted to
analyse space-time clashes and to develop WBS (Work
Breakdown Structure) paths oriented to a better resource
allocation and site construction management, but the lack of
automation in the modelling phase, the impossibility of a
collaborative use, the inability of showing provisional
requirements and non-physical constraints of a building, made
particularly complicated the broad diffusion and usage of these
tools (Webb and Haupt, 2005).
Most of these issues have been solved with the arrival of BIM
platforms and the diffusion of their more advantageous utilities.
The most important features that developed the 4D usage are:
information and changeable parameters included in BIM
elements that are often automatically inserted avoiding the
manual addition necessary in a CAD environment; BIM
workflow foresees the direct generation of a 3D model without
respecting CAD layers hierarchy and saving work time; the
possibility to introduce variations and additional information
that instantly correct the model in a parametric way; the
potential for more specific professionals to work on the same
model in a collaborative and simultaneous interaction (Nehad et
al., 2017). Therefore BIM environment finally allows the
automatic generation of a 4D model that could be continuously
modified and improved, but it also includes many other utilities
developed by the research in the last ten years. 4D BIM
modelling permits time planning visualisation not only through
traditional diagrams used by technicians like Gantt charts and
PERT (Program Evaluation and Review Technique) layouts, but
also through dynamic animations that show construction
sequences that could be enjoyed with the tools of the virtual
reality in a walk-through experience (Sampaio, 2017). The 4D
BIM model is able to be controlled by all the participants to the
construction, evaluating time monitoring from the different
points of view of technicians developing a decision-making
process both for as-planned and as-built evaluations. Indeed one
of the most powerful benefits of 4D BIM modelling consists of
analysing construction phases in order to check interferences
with a virtual simulation of the building site, improving
movements of machinery and people, storage and handling of
resources, always verifying the respect of safety standards and
environmental sustainability (Jupp, 2017).
An important issue that affects the successful outcome of a 4D
simulation is represented also by the level of information and
details equipped in the modelling phase. It is to be expected that
a high level of LOD, about LOD 400, is recommended in order
to better organise all the aspects of construction phases, but
some authors affirm that it is sometimes necessary to shift
between different levels of LOD according to the purposes of
4D BIM simulations, considering ―Multi-LOD‖ evaluations
(Guévremont and Hammad, 2018). For instance major stages of
construction, especially when a great scale settlement is
analysed, do not need a high state of LOD, whereas focus on
single and integrated construction phases, particularly affecting
building parts or components, require detailed information.
Furthermore during the construction process some features
could be changed in the model, as well as some details couldn‘t
be totally predictable due to building site constraints. Therefore
it is possible to consider ―graphical‖ and ―temporal‖ LODs
during the as-planned and as-built phases, that could be
variously changed in the 4D simulation (Boton et al., 2015).
The trend of recent years by major software house is to include
4D BIM utilities in a stand-alone platform, but the construction
of a 4D model and the extrapolation of operational data could
be also reached with specific plug-in additions. Indeed it is
possible to classify three categories of 4D applications:
independent stand-alone software like Autodesk Navisworks or
Trimble Tekla Structures in which 4D utilities are already
integrated; freeware softwares like SketchUp with some 4D
functions integrated and others implemented by additional
plugins; open-source software like FreeCad, for which 4D
utilities must be added with specific applications.
In order to compare these different operational addresses, the
contribution aims to evaluate the achievement of a 4D BIM
analyse using different digital platforms for the project of a
specific case-study.
4. THE CASE STUDY
The proposed example is the BIM modelling of a steel canopy
designed for the improvement of Corso San Giorgio in Teramo,
the main street of a town in the centre of Italy (Fig. 1). This
project, designed by architects Giustino Vallese and Dario
Magnacca and completed in May 2018, was originally
developed by one of the authors of the paper with the use of
Sketchup software, in order to verify all the connection systems
of steel members and the integration between the structure and
technological solutions of envelope. The canopy does not have
a considerable extension, because it develops only 180 square
meters but it has an irregular shape, with an arrangement of the
columns that seems to be apparently chaotic and a plan of the
roof that balances between an orthogonal geometry on 3 sides
and connections with circular arches at the end of the perimeter,
also pierced by a large circular hole to let the light in (Fig. 2).
The designers desire to keep the sheltered structure profile as
thin as possible led to coherent design choices, such as the edge
tapering obtained through the insertion of cantilevered beams
and the withdrawal of external columns, as well as
technological solutions for the roof slab useful for the
containment of the whole structural weight. The need to reduce
the construction time and to guarantee the economic
sustainability of the work forced the use of dry assembly
systems and bolted connections, limiting welding operations to
the only phases operated in the fabrication shop prior to the hot
Figure 1. Rendering view of the steel canopy in Teramo
(Courtesy of Giustino Vallese and Dario Magnacca)
The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XLII-2/W17, 2019
6th International Workshop LowCost 3D – Sensors, Algorithms, Applications, 2–3 December 2019, Strasbourg, France
This contribution has been peer-reviewed.
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109
Figure 2. A rendering view of a curved side and the big circular
hole inside the steel canopy (Courtesy of Giustino Vallese and
Dario Magnacca)
dip galvanization process of steel profiles. The irregular
arrangement of the tubular columns, shaped with three circular
sections, was also imposed by the discovery in the area of the
relics of a previous building demolished at the beginning of the
twentieth century, which the municipal authority wanted to
preserve. This point also led to the choice of the foundation
system, composed by plinths connected by beams, inserted
where the archaeological remains did not insist. The metal
structure of the roof was organized with the hierarchical
arrangement of the main beams, following the rearward
perimeter, and a more regular mesh of secondary beams, both
stiffened by a system of slender diagonal braces made of L-
shaped or U-shaped sections. The perimeter curved profiles had
been firstly thought as calendered beams but later, they were
replaced by welded pieces of straight profiles aligned to the
spring line of the arches, in order to support their curvature. The
connection between the circular columns and the main I-beams
was solved through the design of a special capital, obtained by
the insertion on the head of the columns of I-shaped pieces with
large sections, vertically oriented and connected to the ends by
octagonal plates. The irregular and complex geometry of the
roof required extreme accuracy in the design ofhe numerous
connection plates between the diagonal braces and the main and
secondary beams.
The containment of the structural weights was achieved through
the construction of a wooden floor, that consists of wooden
joists, connected to the underlying steel beams through special
aluminium plates, and nailed OSB panels. The waterproofing
closure of the roof was made of aluminium sheets, connected
together by a mechanical interlocking system that avoided
drilling operations externally exposed to the weather.
The intrados and the perimeter of the canopy, as well as the
tapered parts of the roof, were covered with mirror-finished
stainless steel sheets, joined to the steel structure through a
special mounting profiles.
The decision to test the potential of Freecad in the 4D BIM field
on this specific project was suggested by the complexity of the
work which, despite its small size, constitutes a meaningful
example to check its flexibility in modeling, the arrangement of
irregular geometries and the management of a large number of
components. On the other hand, the participation in the design
phases of the work was a fundamental prerequisite to be able to
deeply consider all the problems related to the construction and
to evaluate the validity of the software for the problem solving.
4.1 The 4D BIM simulation in Freecad
Before proceeding with the 4D simulation in Freecad, it was
necessary to build the model. The ordinary modules for the BIM
platform are the Arch and BIM workbenches, both equal, even
if the second is implemented with specific commands for the
management of the BIM. The modelling process in these two
modules requires the design of each individual beam but, in the
proposed study case, this mode would have taken a long time,
because of the high number of members and the irregular
geometry of the structural system that would not allow to
proceed to an extensive copying and cloning operations. To
overcome this problem, the modelling process resorted to an
alternative modality through the use of a complementary add-
on, Dodo, dedicated to the modelling of steel pipes and profiles.
Dodo, like its predecessor Flamingo, allows to assign certain
Figure 3. The Freecad BIM Model, a bottom view
Figure 4. The Freecad BIM Model, a perspective view
Figure 5. The Freecad BIM Model, a view of a curved side
The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XLII-2/W17, 2019
6th International Workshop LowCost 3D – Sensors, Algorithms, Applications, 2–3 December 2019, Strasbourg, France
This contribution has been peer-reviewed.
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110
Figure 6. The Gantt diagram in ProjectLibre
Figure 7. The Pert diagram in ProjectLibre
profiles to 2d elements processed in Freecad (sketches, wires,
lines or polylines) or to all the elements of each layer imported
by dwg or dxf, with the return of objects structures, the same
valid for the BIM model. Therefore the first step consisted in
the drawing of a dxf wireframe with a CAD 2d, where central
lines of the beams have been shown and divided into layers
according to the types of profiles; later the model was realised
through Dodo, selecting layers and assigning to each of them a
specific profile. This operating mode has proved to be really
fast, remedying the slow and boring design of multiple beams
(Figg. 3-5). The model was improved in the Dodo workbench
with appropriate macro that permitted to extend and to connect
the objects created and it was completed in the BIM module to
insert foundations, connections between the parts and the
wooden covering panels, as well as the assignment of the
materials to each single component and the BIM components.
The material insertion phase revealed a bug in the program that
crashed. In order to overcome this problem, the processed file
was opened with version 0.16 through which it was possible to
easily introduce all the information sheets related to the used
materials; materials were finally assigned to BIM elements and
this operation was also possible with versions 0.17 and 0.18.
Once the model was completed, the 4D simulation started.
Freecad does not have a specific area dedicated to the
management of construction time phases, but in 2016 the user
community developed a specific workbench, called Planner,
(―Macro for BIM simulation of work - Page 3 - FreeCAD
Forum,‖ n.d.) through which it is possible to connect a Gantt
chart, drawn with the Open Source software ProjectLibre, to
different components of the BIM model (Tsvetkov and Petrova,
2013). In this case, Freecad works as post-processing of the data
developed in ProjectLibre. The workflow is simple and it can be
summarized in the following steps: in ProjectLibre a Gantt and
Pert diagrams are drawn on the basis of construction phases
evaluated with the CPM criterion (Critical path method) (Figg.
6,7); the building resources are defined and they are assigned to
Figure 8. Building phases in Freecad according to the Gantt
Diagram exported from ProjectLibre
phases; an xml file is exported from ProjectLibre and imported
in Freecad within the Planner workbench; the import process
includes the Freecad model with appropriate labels, named as
the ProjectLibre phases; the corresponding label is assigned to
each component in the properties panel; the visualisation of the
4D simulation can start. The simulation carried out through
Planner has revealed another small inconvenience; indeed
despite the workbench was installable and appeared in the
version 0.18, the loading of the xml couldn‘t be completed, so
the labels couldn‘t be assigned to components. Also in this case
the version 0.16 was used, furthermore the test was also carried
out with version 0.17 which proved to be efficient. In all
likelihood, the failure is due to the updating of the Python and
Qt libraries. In any case, once the labels are assigned, the
simulation can also be performed with the version 0.18.
4.2 The 4D BIM in Sketchup and Tekla Structures
The modelling in Sketchup was carried out through a free
extension, Building Structures Tool that allows a workflow
similar to Dodo in Freecad. The 4D simulation was carried out
The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XLII-2/W17, 2019
6th International Workshop LowCost 3D – Sensors, Algorithms, Applications, 2–3 December 2019, Strasbourg, France
This contribution has been peer-reviewed.
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111
Figure 9. The Gantt chart in Sketchup via 4D Virtual Builder
Figure 10. The Gantt chart in Tekla Structures
instead with the extension 4D Virtual Builder in trial version.
The choice of this plugin was suggested by the desire to test an
internal functionality of the software, without resorting to the
use of external software, such as Synchro. Through 4D Virtual
Builder it is possible to define phases in a Gantt chart (Fig. 9)
and later to assign them to each elements of the model. The
extension permits also to load the phases from xml files
processed by other software such as MS Project or Asta Power
Project and, unlike what happens in Freecad, allows to
optimally control the visualization modalities of the
construction progress related to the elements assigned to each
phase, and to export the same phases in video format or in
sequences of images (Fig. 10). However, it does not have a
resources management module or tools that are useful to review
the construction site schedule, in the case of unexpected events
that may produce delays. These lacks are partially solved in
Tekla Structures, that dedicates to the 4D control a specific
area
of the software called ―manage‖ in which it is possible to find
all the tools connected with the construction time schedule.
The arrangement of the 4D workflow needs the division of the
model components in different phases that correspond to the
major parts of the construction sequences; this action may
appear as a traditional layer organisation, but it allows to
organise the building sequence also by other criteria like
structural qualities or production and building costs,
remembering that in 2019 the software is provided of a specific
extension called ―Design-to-cost‖ that is useful to make
predictive analysis about the financial commitment of a
building. The phases assignment directly leads to list the
singular construction activities in a specific panel that is able to
control several aspects of the time schedule and that could be
implemented with many information concerning players and
features of the building procedure.
Once created the activities list, it is possible to export it in
different sort of charts (Fig. 11), but above all, to visualize the
construction sequence in a timeline of hours or days, that show
the consecutive steps of the construction (Fig. 12), that could be
Figure 11. Building phases in Sketchup
easily converted in an animation with the Sketchup importation,
with the possibility to automatically produce reports and to
check the safety oriented construction process planning
(Sulanviki et al., 2010).
5. CONCLUSION
The results of the comparison between Freecad and the other
commercial software has revealed some strengths of the Open
Source platforms and some critical aspects. About problems, it
is clear that in Freecad pictures referring to the progress of the
work aren‘t so attractive and well-defined in a communicative
way, as allowed by Sketchup and neither the management of all
the building processes, with the automatic development of the
phases according to the yields related to the resources assigned
to certain processes as in the case of Tekla.
However, it must be recognized that although it cannot rely on
automated processes, alternative operating practices can be used
in Freecad that can overcome these problems and that already
make the software efficient also for a professional use.
In any case, in order to facilitate the visualization of the
construction site phases, it is possible to copy the Planner group
generated by the loading of the Project Libre xml file several
times, and to assign them some of the phases, so as to simplify
the display of singular parts, waiting for a desired improvement
and adaptation of the version 0.18 and Planner. Furthermore the
proposed model consisted of short beams and a large number of
components, which did not ease visual operations, so the
difficulty in visualization could be much less relevant in other
larger models.
About the automatic management of the time of the phases, the
following operating mode is proposed: it is possible to export
information sheets related to the quantities from Freecad; to
connect the exported file in csv to ProjectLibre; within it time
of the phases is determined according to the quantity of
elements and the yield of resource production (example: in the
case of quantities of 200 mc of RC and a resources efficiency of
25 mc / day, the phase lasts 8 day) The potential of ProjectLibre
is only partially exploited by Planner, because the software
allows a project management that appears really advanced, even
if it is not supported by the captivating graphics of similar
The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XLII-2/W17, 2019
6th International Workshop LowCost 3D – Sensors, Algorithms, Applications, 2–3 December 2019, Strasbourg, France
This contribution has been peer-reviewed.
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112
commercial software. A possible development to improve the
interaction between Freecad and ProjectLibre could also
concern the management of the costs related to phases and
resources defined in ProjectLibre, as well as the revision of the
project phases in relation to delays and unforeseen events, that
appears very advanced in ProjectLibre thanks to the easy
management of the baselines.
Figure 12. Building phases in Tekla Structures
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114
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