Before Side Effects Software introduced Houdini, which included the SOP Editor as an integral part of the package, a wide range of geometry processing tools were created to manipulate geometry within a project. These tools - the precursors to SOPs - are still available and, collectively, are called "Geometry Tools".

The Geometry Tools consists of a conglomeration of unix programmes designed for the purpose of processing geometry in various file formats. Although the SOP Editor now performs many of these functions, it is sometimes convenient to use them in custom scripts, or as stand alone command line functions within a c-shell or spy. For this reason they are still available, and you can still access them via the Unix sop.

All Geometry Toolkit programs have on-line help. You need only to type the command name followed by a "-" within a c-shell to obtain a summary of the command usage with a brief explanation of the options.