algorithmic modeling for Rhino



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

Location: In Between
Members: 976
Latest Activity: Feb 5

Download the latest set of gHowl components:

gHowl_r50 and example files


Check out the gHowl videos page where you can see how people have been using gHowl.

Our users have connected Rhino and Grasshopper to various protocols, platforms, and softwares including:



Open Office






Google Earth



Pure Data










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

Elevation Service - This component returns the elevation at the coordinates you supply as inputs.  It queries the Google Elevations API to do this.  There are some limitations on usage, so be warned.



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.

Discussion Forum

Android OSCmessage to GHowl. Error Message. 7 Replies

Hello all,I am writing an android interface to communicate with grasshopper.  It's the same idea as some of the OSC apps in the app store, but they aren't open source and I need to be able to have…Continue

Tags: java, osc, udp, ghowl, android

Started by Jon Blout. Last reply by Konstantin Markin Aug 8, 2022.

Ghowl xml import /export 10 Replies

Hey againHow does it work if you want to import and export the same .xml file, when the ghowl xml import has 4 output parameters, and the ghowl export has 2 input parameteres ?RegardsContinue

Tags: export, xml, Ghowl

Started by Jesper Hildebrandt Andersen. Last reply by Hannah Stevens Apr 14, 2021.

external real time data/ parse xml 5 Replies

hello, i am trying this for the first time and hoping someone can point me in the right direction. i am trying to use grasshopper + ghowl to read real time data from a weather site's API.  i have a…Continue

Started by pwdarden. Last reply by Denis Cox Oct 26, 2020.

problem about UDP receiver

Hi, I am using UDP receiver in gHowl. It works well until I packaged everything into a cluster, and the UDP receiver keeps sayting "AddressAlreadyInUse: you might have opened this socket on another…Continue

Started by vapeur Jul 5, 2020.

Comment Wall


You need to be a member of gHowl to add comments!

Comment by Jason Morenikeji on February 7, 2020 at 4:38pm

I'm having issues with the Spreadsheet Reader (see the error message).
Re: "Solution exception:The process cannot access the file 'C:\Users\user\Documents\2018.xlsx' because it is being used by another process."
Is this is a bug with the Reader?
Another question: the Excel file it reads updated weather data refreshed every minute, how can I ensure the data is also automatically updated in Grasshopper via the gHowl plug-in?
Kind regards,

Comment by IAM on February 18, 2019 at 9:25am

It seems GET ELEVATION component does not work with the current version of Google Earth, could this be fixed easily?


Comment by Kartik on November 6, 2017 at 10:33pm
Comment by Pietro Florio on October 24, 2016 at 3:59am

Hello everyone,

I am trying to visualise a colored mesh in Google Earth (each face has a different color). This mesh was generated in Grasshopper overlapped on a 3D vector of buildings.

I would like to visualise this mesh overlapped on the 3D environment in Google Earth, so that I can see the nice building textures behind my mesh.

It is easy to visualise this mesh via GHowl but ONLY WITHOUT COLORS. Any clue on how to define the color of each face in the mesh?

Should I import them as google earth polygons? Then how do I modify the color/transparency of each?

Since polygons are heavy to visualise, is there a way to visualise faces as points located at the face centroid and then attribute them a color?

Thank you for your reply.

Comment by Ali Mirakbari on May 1, 2016 at 7:30am


I am trying to use ExDReader and it returns a generic error : Illegal characters in path.

the path is: C:\Users\Admin\Documents\CN3\TheSILO\data.xlsx

and I have used this component with this path before! NOw it does not work  with any other xlsx file.

.Net is also updated.

Anybody has had this issue before?

Comment by pyrit on March 12, 2015 at 6:42am

hey there,

can anyone help me with the setup, exporting a simple geo to google earth and display it there in realtime ?

thy !

Comment by Advait on September 15, 2014 at 2:44am

Hi All,

I wanted to impor the kml file to rhino to extract the geometry. is it possible?

Comment by horst Becker on April 30, 2014 at 4:09am

Hi Luis,

I try to export a XML file by using the gHowl XML write component. but I run into some problems. The attached image shows an imported xlm file with the data structure I want to reach. my problem is now that the Import component gives me more Outputs then the write component has inputs.

the import component outputs are: 1. elements, 2.attribute names, 3. Attribute values

write component Inputs: 1. Data, 2. Element Names


How does that come together?


Any hint? Thanks...!

Comment by Javier Armando Figueroa Escobar on January 22, 2014 at 1:57pm

Hi Luis, thanks for sharing such great tool. I've got an issue with sending data from processing through osc. Its a huge string that its sopouse to be sent in real time and i'm already been successful in sending the data, but there is a maximum size of the amount that it been send, after that it simply stop. I could now configure the datagram size of the message in processing, but nothing change, so there is a way of edit the size of the data that i can receive in ghowl?
Only i've noticed that depend on the quality of wireless network,
Thanks a lot

Comment by davide ventura on October 25, 2013 at 8:19am

Thanks Luis, I have already my xively I'm looking for a app for my samsung galaxy a quite old, if you some apps to suggest me..let me Know..muchas gracias!!


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