Interactive Models Based on Virtual Reality Technology Used in Civil Engineering Education - Teaching through Multi-User Virtual Environments - page 390

been changing the way of designing, at least partly.
In general, the designers approve the use of CAD
because it improves designing, but mostly CAD is
still used just as auxiliary means in drawing. But
CAD could easily allow achieving clear benefits
in design project process. For instances, CAD
can make drafting and the creation of alternatives
quicker and more effective along several stages
of designing, including the conception phase. But
for that, it is not enough that designer learns to
use CAD properly, he/she have to also learn to
create and to support their activity with it, which
requires also a new way of thinking and reacting
towards CAD (Penttila, 2005).
The more conservative designers defended that
CAD could merely add to existing design capabili-
ties. But the reality shows that the new technology
continues to change the way we design, rather than
merely augment or replace human drawers. For
instances, in architectural design the 21 st century
world project leads to VR models allowing sharing
geometrically complex and information-rich 3D
interactive worlds over the web (Adamo-Villani,
Johnson & Penrod, 2009).

or with virtual/interactive capacities, concerns
essentially economic and administrative benefits
as a way of presenting the visual simulation of
the expected situation of the work in several step
of its evolution.
Therefore in the construction industry, the
general use of 3D and 4D models is the visual-
ization of the building design for demonstration
purposes to the client, and not as a design support
system. The majority of the industry's clients are
inexperienced in building design and construction
processes. 3D building models are produced to
show the client how their building will look like
if they decided to procure the proposed project.
Provided that the 3D model of the building prog-
ress is generated as construction progresses, this
data can be used for the calculation of interim
payments, schedule control and assessment,
conflict management or avoidance purposes. 3D
and 4D modeling are being used to improve the
production, analysis, and management of design
and construction information in many phases and
areas of construction projects (Fischer & Kunz,
2004). VTT Building Technology has been de-
veloping and implementing applications based on
this technique improving a better communication
between the partners in a construction project
(Leinonen, Kähkönen & Retik, 2003). Note also
the contribution of VR in Architecture/Engineer-
ing, to support conception design (Petzold, Bimber
& Tonn, 2007), presenting the plan (Khanzode,
Fisher & Reed, 2007) or following the progress
of construction (Fischer, 2000).
The didactic VR models presented in the text
shows the sequence of construction processes al-
lowing the visualization of each step. The models
concern a wall and a roof, as significant compo-
nents of a building and two methods of bridges
construction, with different degree of detail and
technical information. VR technology was ap-
plied for educational proposes, targeted to Civil
Engineering students.

Construction

Normally, in the construction contexts, the 3D
geometric models are used to present architectural
projects, showing only their final shape. They
not allow the visual simulation of their physical
modification. The models concerning construction
needs to be able to produce changes of the project
geometry. The integration of geometric representa-
tions of a building together with scheduling data
related to construction planning information is the
bases of 4D (3D + time) models. So, in this field,
4D models combine 3D models with the project
timeline (Retik, 1997), and the VR technology has
been used to turn 4D models more realistic allow-
ing interaction with the environment representing
the construction place. The use of 4D models
just linked with construction planning software