Interactive Models Based on Virtual Reality Technology Used in Civil Engineering Education - Teaching through Multi-User Virtual Environments - page 405

Figure 21. The guards and also other finishing elements are positioned

and it has a menu of events display allowing the
students and teachers to select a specific part. The
camera movement shows the model in a consistent
way to present all sequences of events allowing
the user to perceive correctly the most important
details of this construction method.
The model was worked out attending both
the technical knowledge and didactic aspects
namely in how and what to show. It also attend
that the model is going to be manipulated by
undergraduate students of Civil Engineering.
So, the model could be an important support to
teachers to illustrate bridges construction issues
in class and after, by themselves, using their PCs.
The animation of the construction process can
be visualized at http://www.octaviomartins.com/
lancamentoIncremental/.

As far as the roof drawing is concerned the
initial data needed are: the specification of the
geometric outline of the roof and the slope of each
of the roof planes of which it is made up. Based on
this information the plan of the corresponding roof
is drawn (Figure 22). So, when defining drawings
and 3D models some geometric elements must be
used: the slopes represented by their correspond-
ing right-angled triangles and the elevation lines.
These are shown traced on a plan but they identify
three-dimensional elements (Figure 22).
In order to facilitate the ability to understand
the spatial aspect inherent in the process, a didac-
tic model was created in which all the methodol-
ogy underlying its construction is presented in a
virtual interactive environment. So, when defin-
ing drawings and 3D models of the roof some
geometric elements must be used: the base, the
slopes represented by their corresponding right-
angled triangles and the elevation lines. These are
shown traced on a plan but they identify three-
dimensional elements. In order to facilitate the
ability to understand the spatial aspect inherent
in the process, the didactic model presents, in a
virtual interactive environment all the methodol-
ogy underlying the construction of a roof.
Two basic blocks of roof composes the selected
example. Figure 23 shows the outline of the roof
under consideration and the slope value for each
of the roof planes. When making plan drawings
for roofs made up of more than four planes the
initial form has to be subdivided into quadrangles.

VR model of the Roof

Following from those examples, a proposal was
put forward to generate an educational model
related to the graphic construction of a roof 3D
model. Drawings using elevation projection is one
of the topics in the subject of Technical Drawing
included in the syllabus of the module on Com-
puter Assisted Drawing. This representation uses
only the view obtained by horizontal projection,
the plan. However, the drawing is complemented
by the relevant data, the elevations value and the
graphics related to the three-dimensional space.