gHowl is a set of components which extend Grasshopper's ability to communicate and exchange information with other applications and physical devices.


gHowl is developed by Damien Alomar, and Luis E. Fraguada and Giulio Piacentino.

gHowl code is now available by browsing the gHowl repository on GitHub.



UDP Components now have the ability to send and receive to a Multicast group.  To send or receive to a Multicast group, make sure you use the IP Range of -

OSC functionality is provided by the Bespoke OSC Library by Paul Varcholik.

Network Source - Tests the connection of your machine to a network.

UDP Send - Allows the sending of UDP messages over the network.  Also allows the sending of OSC messages to OSC enabled software and hardware devices. (Deleting this component in 0.7.0057 crashes GH / Rhino)

UDP Receive- Allows the sending and receiving of UDP messages.  Also allows the reception of OSC messages and bundles (from Reactivision for example).(Deleting this component in 0.7.0057 crashes GH / Rhino)

OSC Channel - This component allows the storage of a single OSC Channel.  Change the component's nickname to store that address' data.

OSC Dispatch - This component allows the storage of data from multiple OSC addresses.

The spreadsheet components leverage the OpenXML engine.  You must have OpenXMLSDKV2.msi installed in order for these components to work.  These components read and write *.xlsx files.  Supports numerical values and strings.

Spreadsheet Reader- Retrieves spreadsheet data from a file stored on your computer.

Spreadsheet Writer - Allows you to write a spreadsheet file.

These components retrieve xml data from local and web sources (such as RSS feeds).

Pachube - Retrieves data from a Pachube feed.  Must have a valid Pachube API. (Deleting this component after making a connection in 0.7.0057 crashes GH / Rhino)

Pachube Update - Allows you to update a Pachube Feed.  The component has variable inputs to enable streaming to various datastreams.  Must have a valid Pachube API.

XML Parser - This component parses an XML file stored on your computer or on the web.

XML Writer - Writes out XML



These components aid in the mapping and conversion of coordinates from GPS enabled devices to XYZ coordinates.

Format GEO - Takes NMEA formatted GPS coordinates and converts them to Decimal Degrees.

XYZ -> GEO - Maps XYZ coordinates in Rhino/Grasshopper to Longitude, Latitude, and Altitude.

GPS -> GEO - Maps Longitude, Latitude, and Altitude coordinates to XYZ



KML Exporter - Exports points, curves, and meshes to a KML File.  Breps should be meshed before exporting.  Brep support will be added soon.  Object attributes such as color, transparency, line width, line color, etc will be added soon.

KML Attributes - Adds Fill Color, Line Color, and Line Width to Exported KML Objects.


Support Email: 4FQ.RGS4I@AK3Y3FD4FQRXFzI@
Plug-in rating:
Average: 4.6 (16 votes)
Title Release Notes
gHowl_r50 Components Added: -PachubeUpdate -XMLWriter -ElevationService -KMLAttributes Changes: -The Spreadsheet components have been rewritten to use OpenXML -GPS is now GEO -A few small ext edits  
Version: 0.1.r50.0
Language: English
gHowl_r50 Example Files
Since the examples were getting large they are being provided as a separate download. Thanks to Random[Arq] for providing some examples to interface with VVVV.  
Version: 0.1.r50.0
Language: English
Added KML and GPS components to gHowl.  
Version: 0.1.r49.0
Language: English
UDP, Spreadsheet, and XML components  
Version: 0.1.v46.0
Language: English


hi im having problems with the plugin.

It shows error:

1. Solution exception:The type initializer for 'ClosedXML.Excel.XLWorkbook' threw an exception.


I have excel 2016 installed. any other dependencies?


Best, Mathias

amirali.amirakbari's picture


When I try to open a Excel spreadsheet, the ExDRead component returns a message containing " Illegal charachters in path" .NET framework is updated and I previously installed dependent files(XML Reader) 

Any idea?


hi,I meet a problem."Getelevation" output noting after it finished the working. I just change the name ,and the coordinate,and the .jpg I saved from googleearth(normal).

thank u :)

DennisFRA's picture

Not working for me. 

fraguada's picture

Could you be a bit more specific of what is not working?

DennisFRA's picture

I find it annoying to call it a 'Spreadsheet writer/reader' although it will not read any regular Excel or Openoffice spreadsheet files but only a rare Microsoft mutation of such called '*.xlsx' that can only be created in Excel. 

There is a website however where you can have your *.xls into *.xlsx files. With that it finally worked. A little more information about that strange *.xlsx format would help and why it must be that way.

fraguada's picture

As stated above:

The spreadsheet components leverage the OpenXML engine.  You must have OpenXMLSDKV2.msi installed in order for these components to work.  These components read and write *.xlsx files.  Supports numerical values and strings.

An .xls file is a proprietary binary format from Microsoft and was used until Office 2007.  At that time they introduced the OpenXML standard and the .xlsx file format which became the default for Excel.  Furthermore, you can read and write .xlsx files from OpenOffice, LibreOffice, and Google Sheets.

I write these tools because they interest me.  At first I was interested in supporting Open Office files, then I was interested in opening up the support use cases, and OpenXML SDK was an interesting choice.  If these tools help others, great.  If the tools are not written in the way you expect, then I do appreciate the comments. 

Finally, if you find the use of an industry standard file type such as .xlsx annoying, there are plenty of other implementations of spreadsheet readers and writers for grasshopper.  You could even write your own if none of them suits you.  That might be the only way to truly get across why one developer chooses a specific way of doing things.  You might eventually arrive at the same conclusion, or something completely different.  Several years have passed since the writing of these tools, so most likely there is a better set of libraries to read/write spreadsheets.

Colette's picture

How and where can i find the link to downlad the plugin file please?


fraguada's picture

Do you not see the downloads section above?

ugoili's picture

hey, in starting with grasshopper and GHOWL too. where can i find some complet TUTORIALS?  from start to end.....  TY :)

fraguada's picture

You should check out the example files.

how to install

the same question

Having problems with downloading ghowl_r50

fraguada's picture


I am not sure what the issue is.  It is an issue with the site.  I will check with the developers.

daolang's picture

there is a question,why i can't dowloud gHowl_r50?

the same question

Downloading is working fine for me. The site is slow sometimes, though.

good one!

Hola, me he descargado los ejemplos de "Random[Arq]" y no se como funciona el test de superficie acústica en grasshopper, concretamente tengo problemas con la burbuja "Paht mapper as tree" ¿alguién me podría ayudar en esto?
Muchas gracias de antemano

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