Why Use Ruby Scripts with SketchUp?
When you add Ruby scripts to SketchUp, it's like giving SketchUp special powers to perform a specific task. For example, if you import a CAD drawing into SketchUp, a number of Ruby scripts can help you clean up the file by removing stray lines or searching for lines that should connect but don't. If you're modeling prototypes for manufactured items, a Ruby script that rounds corners can save you hours. The script that you need all just depends on what you're modelling.
What is a Ruby script, you ask? These scripts, or plugins, are just mini-programs written in the Ruby computer programming language that add specific functionality to a main program (in this case, SketchUp). Trimble provides a way for people to make their own plugins but — here's the best thing — to use Ruby scripts (Rubies, for short) that other people have created, you don't have to know anything about Ruby, or programming in general. You just need to install the script, and you're on your way!
This article in SketchUp's online Knowledge Center explains how to install plugins so that you can use them: Installing Ruby Plugins (Extensions).