Chapter 12 Building Information Modeling 293
command. The roof can be modeled in a view
that corresponds to a level at the top of the exte-
rior walls, such as the Top of Plate level. The roof
is modeled based on the specifi c style of roof
used for the building. For example, the roof can
be modeled as a gable, hip, or fl at roof. The exte-
rior walls of the structure are used as a location
reference and a sketch is made to defi ne the area
of the roof. For gable and hip roofs, the roof slope
and slope direction are specifi ed. Additional
features, such as fascia boards, soffi ts, and gutters,
are added to complete the roof.
The same basic modeling process is used for
the other building systems used in the structure.
For example, additional views can be used to
model the mechanical, electrical, and plumbing
systems. The components of each system are
modeled in the appropriate view and each view
is named to identify the content.
Section views and elevation views can be
prepared in similar fashion for the construction
drawings. However, these views are also useful
for design and visualization purposes. These
views are discussed in the following sections.
Section Views
A section view shows a portion of a building
as if it has been “cut.” In parametric modeling,
a section view is created by drawing a cutting-
plane line to represent where the section is to be
“cut.” This process requires picking two points
to locate the cutting-plane line. Then, the section
view is automatically generated by the program.
The
SECTION
command is used to create
a section view. Section views can be created
as building sections, wall sections, and detail
sections. Building sections and wall sections
are normally used in the drawing documenta-
tion to clarify construction requirements. See
Figure 12-16.
Creating section views plays an important
role during the modeling process. Often, creating
a section helps the designer verify feature
locations or visualize features to be modeled. A
common process is to create a section view in
order to edit the profi le of a feature, such as a
wall. After creating the section view, the view is
displayed and the wall is edited by editing the
sketch of the wall. This technique can be used
to create a “cutout” in a wall or an architectural
feature, such as a radial curve at the top.
and furniture are usually included with the
software and can be loaded into a project as
needed. Some product manufacturers supply
fi les on their websites for the same purpose.
The fl oor of the building is commonly
modeled when creating the fl oor plan. A fl oor is
created using the
FLOOR
command. The appro-
priate fl oor type is selected and a sketch is
made to defi ne the area of the fl oor. The fl oor
represents the type of fl oor framing used and is
made up of the structural materials used in con-
struction, such as wood joists or a concrete slab.
To complete the fl oor plan, additional com-
ponents, such as casework, appliances, fi xtures,
and stairs, are added. As components are placed,
editing tools can be used to help in the process.
Editing tools are used for moving or rotating
components, making copies of existing compo-
nents, creating mirror copies, creating arrays,
and trimming and extending geometry. These
tools are similar to standard editing commands
used in 2D CADD software.
The fl oor plan can be duplicated if a similar
type of plan is needed in the construction doc-
uments. For example, to create a furniture plan,
a duplicate of the fl oor plan can be made and
used to add the furniture. The visibility settings
in the fl oor plan are then adjusted to turn off the
display of furniture.
If the building has a second fl oor, another
fl oor plan view can be created by creating a
level named Second Floor and assigning it to a
view named Second Floor Plan. Then, objects
are added to the second fl oor of the model. If
there are objects from the fi rst fl oor that are in
the same locations on the second fl oor, such as
interior walls, they can be copied using a copy-
and-paste operation.
Other views are used in similar fashion to
construct additional building systems in the
model. For example, to create the building foun-
dation, a view named Foundation Plan can be
used. The view is set to the appropriate level for
creating the foundation walls. Once the walls are
created, structural components such as footings,
columns, and beams are added. A foundation
with a basement also includes a structural fl oor,
interior walls, and any additional components
located in the basement. See Figure 12-15.
The roof of the structure is added by creating
a roof system that uses the materials in con-
struction. A roof is created using the
ROOF
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