# First we pull in the standard API hooks. require 'sketchup.rb' require 'extensions.rb' Sketchup::require 'su_sandbox/GeometryHelpers' (1) They do not really "pull in the API hooks". (2) You only require scripts and libraries, if this script (which has the require statements,) are going to use what is defined in them. And your script uses nothing in those two files. (The files are located in the "Tools" sub-directory, of SketchUp program directory. They are not scrambled and can be read. Also everything defined in the "extensions.rb" file, is explained in the API dictionary under the SketchupExtensions class.) (3) require statements are always best located at the top of a file, since they should be dependencies. If they cannot be loaded, the rest of the script should not be run, because a LoadError exception will be raised.