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: 860
Latest Activity: on Sunday

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

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.

Add precision to XYZ to GEO component

Currently the output of XYZ-GEO is in Decimal degrees with grasshopper's standard six decimal places. This limits the precision of real world data to about 10cm. My application generally requires 1…Continue

Started by M11S Feb 3.

Unknown variations in XYZ-GEO output

I have a series of points as the input to the XYZ-GEO node and the output is not consistent with the input. The windows below shows the input and output of XYZ-GEO. Around point 15 the output appears…Continue

Tags: GEO

Started by M11S Jan 31.

Elevation service with Google API key

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 Nov 23, 2015.

Comment Wall


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

Comment by Luis Fraguada on November 6, 2011 at 5:18am

What I do is to bring in a screenshot from Google Earth through the picture frame command in Rhino, I scale it according to the scale indicated (to 1:1) then I pick a point in XYZ which I can easily look up in google earth, such as a sharp corner.  I bring in the xyz to gh, and I write in a panel its corresponding {lon,lat,0}.  You can then use the XYZ>GEO component to convert any points you draw or generate in Rhino / GH from XYZ coordinates to {lon,lat,alt} coordinates.  You can now feed these into the elevation component.

Comment by Igor Mitrić Lavovski on November 5, 2011 at 8:33pm

Or to draw a GPS route with

and use that for coordinates and terrains line...

I will try this one..

Still if you have some cleaner way, I am open :)


Comment by Igor Mitrić Lavovski on November 5, 2011 at 8:27pm

Thanks for that!

How do you get a list of a points (coordinates), do you manually draw them on google earth map with placemaker, than read a coordinate and then assign them in a GH?

I hope not :)

I manage on this way, following your explanation somewhere in forum, to send a model in to google earth.


Comment by Luis Fraguada on November 4, 2011 at 9:51am

Hello Igor,

The Elevation Service needs you to provide a coordinate like this:


*notice the brackets, it is formatted like a GH point.

Longitude and latitude are in decimal degrees.  The component returns the elevation at that point.  Let me know if you need any more information.

Comment by Igor Mitrić Lavovski on November 3, 2011 at 6:42pm

Hallo Luis,

Can you maybe explain a GetElevation option.

Do I need to get familiar with google maps Api pr. and get data from them, and than plug this data to GE node?



Comment by Luis Fraguada on October 14, 2011 at 2:43am

Hello Lauren,

Open Office is not necessary anymore.  Everything you need should be in the gHowl download.  Check out the 'Dependencies' folder for an installer which will enable spreadsheet functionality.  Which version of Rhino/Grasshopper/Windows are you using?

Comment by Lauren Campbell on October 13, 2011 at 1:01pm

I've downloaded Ghowl several times along with the open office and the other thing it says you must have and still can not figure out how to get the components in GH

Any help would be fantastic

Comment by Luis Fraguada on October 5, 2011 at 2:18am

Elise, very cool!  Can you let us know a bit more about this?  Was it as simple as 'plug and play' or did you run into issues along the way?  I wonder how this would operate with multiple users, 10, 100, 1000, etc!  How does the architecture negotiate that information?

Comment by Matas Ubarevicius on October 4, 2011 at 12:34pm
Great work Elise. At the moment I'm writing theory thesis on exactly this kind of interaction ;) That is a ground breaking thing...
Comment by EliseElsacker on October 4, 2011 at 11:11am
Imagine an architecture that reacts on affective, expressive or cognitive signals via Brain Computer Interface Technology

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