Modeling a Complex Structure - Google SketchUp Workshop: Modeling, Visualizing, and Illustrating - page 208

Tip
Once imported, the plan and section JPEGs are “quasigroups”: Although
they can be selected with a single mouse click, they do not appear in the
Outliner. Resist the temptation to Explode and Group them so that you can
name them. If you do that, you will not be able to see the plan and section
images when you are inside other groups, which can make modeling a
little tricky, to say the least.
Stage 3: Constructing the Path of the First Girder on Plan
Objectives : To construct the “scaffolding” for the path of the first girder.
Data : The model obtained in stage 2.
Tool : SketchUp Pro.
The problem that now needs to be confronted is that all the girders in the
construction are “cranked”: They are bent both on plan and elevation. Working
planes now have to be constructed that will allow the paths of the girders to
be drawn in situ. As previously stated, drawing a straight girder and then try-
ing to bend it will get you nowhere.
The first step is to draw the path of the girder on the plan. What we
are trying to achieve here is a simple vertical face bent at some point
along its length. Unfortunately, SketchUp does not allow you to extrude
simple lines, so a 2D surface containing the bent line must be created
and then Push/Pulled to the required height. This produces a volume,
but only a simple surface is required; so any unwanted edges can simply
be deleted using the Eraser tool. Group the working plane and give it
a name.
FiG 12.3 The profile of the first girder traced on plan: Extrusion of the profile with Push/Pull is followed by the removal of unwanted edges.