A Virtual House - Google SketchUp Workshop: Modeling, Visualizing, and Illustrating - page 171

elements that would be difficult to model in SketchUp, for example, objects
that need to have parametric data input.
The second argument in favor of SketchUp is the lower number of faces
that are produced when modeling, something that can greatly reduce the
calculation time for a rendered image.
Third is SketchUp's ability to communicate a project clearly and unambigu-
ously, either with a client or with those involved in the construction process.
The fact that the client can understand the project immediately means that
decisions are made more quickly.
Techniques Used
Many users make great use of layers when they work with SketchUp; however,
SketchUp's layers do not work in the same way as those in other CAD programs.
In SketchUp, the following approach should be employed: All faces and edges
should be drawn on Layer0. Then, they should be either grouped or made into
components and then assigned to a particular layer. Only groups or compo-
nents should ever be placed on a layer other than Layer0. Layers are used for
project organization and to simplify the workspace by only showing the ele-
ments being worked on at any given moment.
For this project, two Ruby plug-in scripts were used:
• Push-PullZ:Thisplug-insavesanenormousamountoftimewhen
modeling roofs. The roof pitches are first modeled as simple faces. Then
the faces that are to be push-pulled (i.e., given thickness) are selected. The
plug-in is then chosen from the Plug-Ins menu, and a dialog box appears.
The desired thickness is entered here, OK is clicked, and the roof pitches
will be extruded in the Z axis (not perpendicular to the surface, as the
standard Push-Pull tool does). Any other modeling can be carried out
using SketchUp's own Push-Pull tool.
• ReverseFaces:AfterchoosingitfromthePlug-Insmenu,thisRubyscript
allows you to change the orientation of a face by using a simple left-click.
With the default material, the face is either beige (exterior) or blue-gray
(interior). Most rendering engines will not “see” a face if its interior is
pointing outwards (if it is “flipped”). If a face in the SketchUp model is
flipped, it will simply be ignored during the render calculation, and your
model will appear to be full of “holes.”
Tip
If you have applied materials to faces, you cannot tell whether they have
been flipped or not. If this is the case, change the Face Styles display mode
to Monochrome to see all faces in the default color. You will then be able
to see each face's orientation and to change any flipped faces using the
Reverse Faces plug-in.