Try the Diagram Editor now!

Use the Editor in Google Wave (discontinued).

Watch the screencasts showing the editor in Google Wave or Google+ Hangouts.

Check out our MIT-licensed source code on GitHub.

December 23, 2010

Hello, Shared Spaces!

Update (Oct 15, 2011): Google has discontinued Shared Spaces and integrated its technology into Google+ Hangouts. The Editor for Shared Spaces is no longer available, but you should check out its integration into Google+ Hangouts!

Google has created a new home for Wave gadgets: Google Shared Spaces. Google says it is an “easy way for you to share mini-collaborative applications, like scheduling tools or games, with your friends or colleagues”. Of course, you can also include our very own Editor in a Shared Space. To get started with a new Space, just click here and send the link to your friends inviting them to a collaborative modeling session! To participate, they just need a Google, Twitter or Yahoo account.

PS: Are you planning on developing your own gadget for Shared Spaces? Check out our syncro library for concurrent editing.

August 8, 2010

Good Bye, Wave!

Some days ago, Google announced that it will stop working on the Wave project. That made us kind of sad as we had fun working with this awesome product and we enjoyed talking to the Wave developers at the Google I/O 2010. We are now wondering, what crazy project the guys from the Wave team will start up next...

By the way, if you want to learn more about our development experience with Google Wave, you should check out our bachelor theses. They are available for download and also cover some interesting technical details of the editor.

It was fun working together with you all and thanks a lot for your valuable feedback! If you have any further questions about the team or our editor do not hesitate to drop us an email.

Good bye!
the team

PS: If you need to get your models off the Wave before Google shuts off the Wave servers, check out our new export feature.

August 6, 2010

New Features: Export and Import of Models

The most requested features for the editor are the export and import of models. We listened to our users and are pleased to announce the integration of those most requested features. From today on you can export your models from the Editor to the web-based ORYX editor, where the models can be further processed and saved in various formats (including PDF). In addition to that, you can also import your models from the ORYX editor repository to share them with your fiends in the Wave. Read on to learn, how you can use those two brand-new features of the editor.

Export of Models
  1. Add our gadget to a wave, choose one of our six modeling languages and create a model of your choice.

  2. Click on the new "Export to the Oryx editor" button in the toolbar.

  3. A new tab opens that should show the created model inside the Oryx editor. At this time, you are able to export the model in various data formats: XPDL, RDF, ERDF, BPMN 2.0 DI XML or JSON. The options that are available are shown in the export menu in the Oryx toolbar on the right.

  4. For more export formats like PDF or PNG, you need to save the model into your personal model repository, first. However, saving via the save button only works for logged in users. Therefore, please open a new browser tab and visit You will see the global repository with public models created by Oryx users and shared with the world. To log in, enter your OpenID in the top right corner of the page. If you don't have an OpenID yet, you can get a free one here:

  5. Once you are logged in, return to the tab with your model from 3. Now, you can click the save button, enter a name for the model, and save it to your personal process repository. When you return to and refresh the site, it should now show your new model. Of course, your model is by default not shared with anyone else and can only be accessed from your OpenID account.

  6. If you now select your model by clicking on it, you can find various export options at the bottom left corner of the site. Click on one of the links, like SVG, PDF, PNG to export your diagram in these graphics formats.

Import of Models

  1. Go to and login with your OpenID. Now, you can see all models that you have access to.

  2. Click on the model you want to import to the editor. Make sure that the model is public by checking the access rights in the top right corner. At the moment, it is only possible to import public models to the Wave, so if your model is not public yet, click on the publishing icon.

  3. When you are sure the model is public, double-click on the model to open it in the Oryx editor. Look for the export menu in the Oryx toolbar and choose "ProcessWave This!".

  4. A new window opens that asks for permission to create a new wave. Click "continue".

  5. The new wave with the title "Oryx Model Export" is shown and contains a editor gadget with your model. You can now rename the wave, invite friends to model collaboratively or even export the model back to your Oryx repository via the export button.
We hope the tutorials above cover every aspect and you enjoy getting your models exported or imported. If you have any further questions about the new features, please leave a comment or send us an e-mail.

July 26, 2010

Our Google I/O presentation on YouTube

Our talk at this year's Google I/O is available on YouTube. Check it out! The presentation of our Editor starts at minute 25.

June 1, 2010

Google I/O 2010 Wrap-up

We are back from Google I/O 2010. It was an awesome experience for us! We got a lot of valuable feedback and had many interesting conversations. Thanks to all of you who joined us in the sandbox or during our talk.

PS: For those of you, who could not attend the I/O: Starting next week you will be able to watch our talk on YouTube.

May 18, 2010

The Editor

We are happy to announce the release of the Editor, a fully collaborative diagram editor for Google Wave.
The Editor is a new approach to modeling tools, aiming to make the creation of diagrams an inherently collaborative process.

Try it out now!
Try the Editor now by using the installer in this Wave.

Watch the screencast

Real-time collaboration

The Editor utilizes the technology of Google Wave: No matter how many people are editing one diagram, changes will be propagated in near real-time.

To make keeping track of changes easy, a changelog lists all actions that were performed on the diagram. Additionally, the changelog doubles as a time machine. With it you can revert the diagram to any previous state it was in at some point of time.

To communicate with other modelers you can annotate the diagram by simply drawing on it. This way you point out modeling errors and suggest improvements. You can also use this feature for real-time communication, e.g. to support a point you make via voice chat.


The Editor is open sourced under the terms of the MIT license. It offers a powerful plugin system which makes it easy to add new features as well as modeling languages. You can check out the code on

Five modeling languages

The Editor is based on the mature web-based diagram editor ORYX. We currently support five modeling languages:

April 19, 2010

Screencast of Modelling Tool for Google Wave

We've created a screencast to show you an early beta version of our collaborative modelling tool for Google Wave. Enjoy!

The modelling language seen in the video is the "Business Process Modelling Notation" (BPMN). To suit your modelling needs, our editor also supports
Right now we are working on some exciting new features and optimizations (like improving the loading time). So stay tuned and watch out for our public release at the end of May 2010!

April 16, 2010

It's alive! Real time collaborative modeling in Google Wave

We are currently working full time on our project of integrating the ORYX editor into Google Wave. We aim to provide a fully featured real-time collaborative diagram editor. Here's a quick rundown of what we have accomplished so far:

Real-time collaboration

Your diagram is kept in sync over all of the connected clients which means that you can see the actions of remote users just as they are being performed. Adding new users to a modeling session in progress is a breeze: Just invite them to your current Wave.

Distributed Undo and Redo

Users expect modern applications to provide undo and redo functionality. Though this is significantly harder to implement for a collaborative and distributed application, we have found a reliable and intuitive way to make undo work just as you would expect it to do in a single-user application.

Farbrausch - easy user identification by colors

To make tracking changes easy, all model elements cast colored shadows. Because each user has a unique color associated with them, it is very easy to see which shape was edited by whom. If you want to know more, a tool tip will provide you with further information.

February 11, 2010

The big picture

So far we've blogged about robots, gadgets and a JavaScript library. Maybe it will suprise you that all of these form the foundation of a very ambitious project: We are working on integrating a large open source software into Google Wave to make it fully collaborative.

Wave is great for creating documents collaboratively. Our vision is to enable all these break-through collaborating features in a modeling tool (think: web-based Visio). Therefore, we are working on the integration of a process model editor called "Oryx" into Google Wave. Never heard of Oryx? Well, let's hear some facts: Oryx is a graphical process model editor that runs in the browser. The Oryx project has been started in 2006 and is fully open sourced under the MIT license. It was initially designed for the creation of business process models using the Business Process Model Notation (BPMN), Event-driven Process Chains (EPC) or Petri Nets. However, because Oryx is extensible via plugins the technology can be used to create all sorts of different models such as UML class diagrams and even GUI prototypes.

We want to make Oryx collaborative in a way that enables multiple users to edit a model simultaneously. Imagine seeing other people dragging shapes around in real-time or an awesome playback feature that shows you how the model evolved.

We are very excited about this project because it is to our knowledge the only endeavour to integrate a large software product into Google Wave.

We'll keep you posted.

February 4, 2010

syncro: Real collaboration in Google Wave gadgets

When Google Wave was first announced, excitement was high among developers. For the first time there would be a platform to enable real-time collaboration not only when editing text but also in all kinds of embedded applications. Google called them gadgets.

Disappointment ensued when it became obvious that the great collaborative text editing features were not available inside of gadgets. Instead Google provided a shared gadget state, a simple key-value storage that is kept in sync across all clients. While this model of a shared state is very easy to pick up, it does not lend itself to creating complex applications. Let's have a look at a simple example: Imagine we want to create a simple application that allows us to create shapes on a canvas and move them around.

The gadget state for this application could look like this:
"next_object_index" : "3"
"0": "{'type': 'rectangle', 'x': 128, 'y': 256}"
"1": "{'type': 'rectangle', 'x': 512, 'y': 0}"
"2": "{'type': 'circle', 'x': 256, 'y': 0}"
Each time a user wants to create a new shape, they insert a new key-value pair to the gadget state using the value of next_object_index as the key. Afterwards, the value of next_object_index has to be incremented. If the position of a shape changes, the user updates the according attributes in the key-value pair representing the object.

There is a problem to this approach widely known as "lost update": When two users create a shape at the same time, they are likely to do so using the same key. If this happens, the update from the user with higher latency will overwrite the other update. Similarly if a user with high latency changes the position of a shape, this update might reach the server with a high delay, causing another position update which actually happened afterwards to be overwritten.

To address this issue we could encapsulate each change to the model (e.g. shape creation, position change) in a single command object which is stored under a unique key in a unambiguous chronological order in the gadget state. This allows the commands to be applied after another so every client has the same view on the model state. This is a fairly common design pattern known as the command pattern. However, this raises two new problems:
1) How do we generate unique keys within the gadget?
2) How do we maintain a chronologically ascending order of commands which is the same on all participating clients without a central coordinator, i.e. in a distributed way?

Introducing syncro

We have written syncro, JavaScript library for Google Wave gadgets to solve these problems. Syncro provides an interface to a
command stack stored in the gadget state. The library ensures unambiguous chronological order of all commands pushed to this stack.

The interface to syncro is dead easy. The library has to be initialized with two callbacks:
syncro.initialize(initializeCallback, newCommandCallback);
The initializeCallback is executed when the gadget is loaded. It receives all commands on the command stack as a parameter in the order they must be applied in.
function initializeCallback(commands) { 
 for (var i = 0; i < commands.length; i++) {
ThenewCommandCallback is executed every time a new command is pushed to the command stack. It receives three arguments: the new command, an array of commands that need to be reverted because of delayed updates as described in the example above and an array of the commands that have to be applied after reverting.
function newCommandCallback(newCommand, revertCommands, applyCommands) { 
 for (var i = 0; i < revertCommands.length; i++) {
 for (var i = 0; i < applyCommands.length; i++) { 
newCommand is always identical toapplyCommands[0] and just passed for convenience. Finally, you are able to push new commands to the command stack with the following function:


There is a little collaborative drag and drop gadget demonstrating the capabilities of syncro. You can use it as an entry point to start writing your own gadget with syncro. Try it out in our public syncro wave in the Wave Sandbox.
Gadget url:
Gadget installer url:

Get the code

The library itself and the example are licensed under the terms of the MIT license. You can get it from our bitbucket repository:

Known issues

Google currently limits the gadget state size to 100 kilobytes. If your Wave
crashes while using the provided example, the command stack may have exceeded the granted memory.
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