Architectural_Design_with_SketchUp

Chapter 6
Creating Geometry
Using Ruby Scripting
In this chapter, we will create scripted geometry in SketchUp. Often called computational
geometry, this is an exciting current topic that allows you to produce 3D shapes and arrangements
that are impossible (or at least hard) to create by hand. Scripting in SketchUp also allows
you to automatize repetitive tasks or facilitate data exchange with text files.
Key Topics:
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What is computational geometry?
Using Ruby Scripts in SketchUp
Working with multiline editors
Introduction to Ruby
Overview of SketchUp’s API
Creating scripted geometry
Transforming geometry
Modifying geometry based on attractors
Why Computational Geometry?
Even to the most seasoned SketchUp user, some tasks are challenging to complete by hand,
using only the tools SketchUp provides. A good example is the creation of copies of a component
where all the copies need to be placed at locations that vary not only linearly (e.g., “place
a copy every 16 inches”) but also in intervals that are determined by a formula (e.g., where
the y coordinate is determined by the square of x—which, of course, results in the shape of
a parabola; see Figure 6.1).
Another example is a curved building whose window-shading devices need to be designed
such that the degree to which they shade or open is determined by how far they deviate
from the southern direction. (See Figure 6.2.)
Such tasks can sometimes be accomplished using one of the available plugins. However,
those plugins are usually limited to the supplied feature set and are hard or impossible to
modify to your needs. As it turns out, some complex tasks may actually be easier to script in
a few lines of code than to model by hand.
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