|Developer(s)||Robert McNeel & Associates|
|Initial release||September 2007|
|Stable release||1.0 / April 4, 2014|
|Operating system||Windows (2000/XP/Vista/7)|
Grasshopper is a visual programming language developed by David Rutten at Robert McNeel & Associates. Grasshopper runs within the Rhinoceros 3D CAD application. Programs are created by dragging components onto a canvas. The outputs to these components are then connected to the inputs of subsequent components. Grasshopper is used mainly to build generative algorithms. Many of Grasshopper's components create 3D geometry.[ex 1] Programs may also contain other types of algorithms including numeric, textual,[ex 2] audio-visual[ex 3] and haptic applications.[ex 4]
"Popular among students and professionals, McNeel Associate’s Rhino modelling tool is endemic in the architectural design world. The new Grasshopper environment provides an intuitive way to explore designs without having to learn to script."—AEC Magazine
The first version of Grasshopper, called Explicit History at the time, was originally publicly released in September 2007. It is currently in beta phase development and is offered as a free download without expiration date, although a licensed copy or un-expired trial of Rhinoceros 4.0 or higher is required to run the software. Grasshopper will become part of the standard Rhino toolset, meaning that Grasshopper 1.0 will be available in Rhino 6.0. 
Node based editor
The main interface for algorithm design in Grasshopper is the node-based editor. Data is passed from component to component via connecting wires which always connect an output grip with an input grip. Data can either be defined locally as a constant, or it can be imported from the Rhino document or a file on the computer. Data is always stored in parameters, which can either be free-floating or attached to a component as input and outputs objects.
In the image above we see three free-floating parameters that are hooked up to a subtraction component. The two yellow boxes on the left both define a set of numeric constants. The top-most panel contains four integers (6, 7, 8 and 12) while the bottom-most panel contains only a single value. These floating parameters supply the subtraction component with input data, which results in four output values (6-5=1, 7-5=2, 8-5=3 and 12-5=7). The same result can be achieved using textual expressions and an evaluator component. In this fashion Grasshopper allows users to combine both visual and textual programming within the same environment.
Grasshopper features a fairly advanced GUI with a lot of features that are only rarely found in production software. It is not known however whether these elements improve or impede effective usage. The main window consist mainly of the component 'palettes' and the 'canvas', apart from standard Windows GUI elements such as the title bar, the menu and the status bar. Since Grasshopper is a plug-in to another windowed application, the layout of the main window is kept minimal. Below is a list of some of the more rare GUI elements.
|MDI||The multi-document-interface menu contains small preview images of the documents in question|
|Find||The Find dialog provides both textual and spatial feedback regarding the search hits. Objects are highlighted on the canvas by a Metaball outline and little arrows on the dialog point towards the location in screen space of the associated component.|
|Prediction||A Markov-chain database is maintained of all the add actions of the user. This enables Grasshopper to (eventually) predict with a reasonable level of accuracy which command(s) will be called upon next. These commands are placed in an easy access toolstrip on the canvas.|
|MRU||The Most-Recently-Used menu maintains not just a large collection of previously used documents, but also checks each file for availability. Files which are no longer present on the system are shown greyed out. In addition, the history of the MRU is categorized into distinct period such as "Just Now", "Today", "Thursday" and "Last Week", making it much easier to find a needed document.|
|ZUI||Some objects drawn on the canvas adjust their display based on the zoom-level. This results in a cleaner and faster view when zoomed out and useful additional information when zoomed in.|
|Color||The default color picker supports and displays transparency.|
|Search||The search function which is used to locate specific components and data types uses both exact and fuzzy comparisons. If the search result list contains too few hits, Levenshtein distance comparisons are added.|
- A sample of grasshopper generated formsAkos, Gil; Parsons, Ronnie, (Blog), StudioMode Beta http://studiomode.nu/ Missing or empty
- A list of functions to link to datastreams containing numbers and text information Fraguada, Luis. "LaN co-director".
- Andrew, Kudless (July 2011). "Biodynamic Structures Workshop". California College of the Arts, San Francisco: AA San Francisco Visiting School. pp. http://www.flickr.com/photos/tags/biodynamicstructures/. Retrieved Feb 9, 2011.
- Payne, Andrew, http://www.liftarchitects.com/journal/2009/9/8/using-a-wii-nunchuck-to-control-grasshopper.html Missing or empty
- Architectural engineering
- Design computing
- Comparison of CAD software
- Visual programming language
- Generative Design
- Tedeschi, Arturo (January 2011). "Intervista a David Rutten". MixExperience Tools1 (in Italian - English) (Naples, Italy: MixExperience). pp. 28–29. Retrieved February - 8 - 2011. Check date values in:
- Loomis, Mark (Dec 23, 2010). "About Generative Design platforms by Mark Loomis" (Blog). Designplaygrounds.
- Loomis, Mark (Jan 10, 2011). "Rhino Grasshopper VS Generative Components" (Blog). Designplaygrounds. Retrieved Feb 9, 2011.
- Jae, Woo (September 2009). "Grasshopper Workshop". Cornell University: Cornell University. Retrieved Feb 9, 2011.
- Michael, Chen (2009–2011). "Crisis Fronts Degree Project". Pratt Institute, NY: Pratt Institute, NY. Retrieved Feb 9, 2011.
|last2=in Authors list (help)
- Andrew, Kudless (February 2010). "Formations 2010". California College of the Arts, San Francisco: California College of the Arts. Retrieved Feb 9, 2011.
- Marc, Fornes; Payne, Andy (August 2010). "MATERIAL RESONANCE WORKSHOP". Sam Fox School of Design & Visual Arts, Washington University St. Louis, Missouri: Sam Fox School of Design & Visual Arts. Retrieved Feb 9, 2011.
- Miller, Nathan (2010–2011). "USC ARCH 517". University of Southern California, CA: University of Southern California, CA. Retrieved Feb 9, 2011.
- Estévez, Prof. Alberto T. (2010–2011). "Master's Degree in BIODIGITAL ARCHITECTURE". ESARQ School of Architecture Universitat Internacional de Catalunya, Barcelona: ESARQ School of Architecture Universitat Internacional de Catalunya, Barcelona. Retrieved Feb 9, 2011.
- Westlake, Michael; Tansey, Alan; Keough, Ian; White, Joe (2010). "Club de Futbol Monterrey". ACADIA 2010 - Association for Computer Aided Design in Architecture, Exhibition Catalog (United States: PrintingHouse Inc, WI) 1 (1): 142–145. ISBN 978-1-4507-3472-1. Retrieved Feb 9, 2011.
- 2. Gensler (August 2009). "BIM analysis for Form and Façade". Shinkenchiku-sha Co.. Ltd. Retrieved 7 February 2011.
- 3. Day, Martyn (June 2, 2009). "Rhino Grasshopper". AEC Magazine. Retrieved 7 February 2011.
- Rutten, David (2013). "Back home". I Eat Bugs For Breakfast.
- K Lagios, J Niemasz and C F Reinhart, "Animated Building Performance Simulation (ABPS) - Linking Rhinoceros/Grasshopper with Radiance/Daysim", Accepted for Publication in the Proceedings of SimBuild 2010, New York City, August 2010 (full article).
- J Niemasz, J Sargent, C F Reinhart, "Solar Zoning and Energy in Detached Residential Dwellings", Proceedings of SimAUD 2011, Boston, April 2011
- Arturo Tedeschi, Architettura Parametrica - Introduzione a Grasshopper, II edizione, Le Penseur, Brienza 2010, ISBN 978-88-95315-08-9 (Italian)
- Arturo Tedeschi, Parametric Architecture with Grasshopper, Le Penseur, Brienza 2011, ISBN 978-88-95315-10-2