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: 892
Latest Activity: 11 hours ago

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

kml exporter issue

Hi Luis Fraguada and team,great job you have done here with this tools, thank you very much for your dedication.I have found an issue though, and dont know how to surpass it. When i use the kml…Continue

Tags: dimension, z, no, exporter, kml

Started by Afonso Portela Mar 19.

Colored Mesh from GH to Google Earth

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…Continue

Tags: earth, google, attributes, mesh

Started by Pietro Florio Oct 24, 2016.

Elevation service with Google API key 1 Reply

Hi Luis, would it be possible to use a Google API key with the Elevation service to extend the quotas of the free service? ThanksContinue

Tags: API, Elevation

Started by Mathias Gmachl. Last reply by Govizlora Jun 6, 2016.

UDP Receiver, OSC Dispatch Question 1 Reply

Hi everyone,I am new to rhino and grasshopper and I am sure this is a simple question. I was wondering if someone could help me understand how to unpack and parse OSC messages correctly. I have found…Continue

Tags: Receiver, UPD, Dispatch, OSC

Started by Elliott Mackie. Last reply by Thomas J Martinez Apr 2, 2016.

Comment Wall


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

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 amirali amirakbari 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!!

Comment by Luis Fraguada on October 25, 2013 at 5:33am

p.s. you could simulate some data on your own if you have a smartphone of some sort with GPS.  There are many free apps which allow you to track the sensors on the phone as well as the GPS location.  If you get one of those apps, I can help you to modify the example to work with the data that you capture.

Comment by Luis Fraguada on October 25, 2013 at 5:31am

Ah. I see what you mean.  This data was indeed directly captured by the ASKit.  Pachube became Cosm, and now it's called Xively.

I have not tried, but I believe the pachube component still works (need to check that).  It should allow you to get data from that service.  Otherwise, you could use the XML Parse component to read data in from the Xively service.  You will probably need a Xively API key.

The ASKit eventually became the Smart Citizen.  It is actually quite different than the ASKit in terms of how good the hardware is.  I did not work on the Smart Citizen project, but the people that did are great engineers and have made an amazing platform.  Also the web platform is fantastic.  The idea here is not just to collect data, but to create a community of people that are also interested in this.  The Smart Citizen kit is meant to be in a static location, where the ASKit was a mobile kit with GPS.

Comment by davide ventura on October 24, 2013 at 8:34am

hi Luis, I'm referring to the "ImportData" example: in that case you used CPH_data. My question is exist something like a web platform were I can download other data in .csv extension like your CPH_data? For exemple something like pachube where people load own data for exemple monitoring own house etc..I try only to taste this tools, that's all!!   And for I have another question:  did you develop an affordable version of "Askit"?


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