Loops in Grasshopper

The visual scripting environment “Grasshopper” for the popular 3D computer graphics and CAD application “Rhinoceros 3D”, enables architects and designers – a group that usually is not very proficient in computer programming – to complement their work with their own scripts. However, some basic programming routines which are common in almost every high-level programming language are missing in Grasshopper. One of these is the ability to program loops. Thus the user has no possibility to continually repeat a task until a certain condition is met. Plug-ins and workarounds enable Grasshopper users to gain this ability back to some degree; however, none of these fully replaces a build-in loop routine. This paper will look at some of these workarounds to provide the user with an overview. Future work will examine loop based procedures in other visual programming languages in order to give feedback to Grasshopper developers about how such a loop feature could look like.