[Robotics] OpenGRASP, COLLADA and Blender

[Séverin Lemaignan]

Hello Antonio,

(I'm speaking here for the MORSE team)

> Following recent messages, let me talk about the work regarding COLLADA for robotics which we have been doing within the European funded project GRASP  which we think could be of interest for you. One of the main tasks of the project has been the development of a simulation tool focused on robot grasping. We chose OpenRAVE (http://openrave.programmingvision.com/en/main/index.html) as the core of toolkit which also includes additional tools, plug-ins and robot models. We call it OpenGRASP (http://opengrasp.sourceforge.net/)

Thanks for getting in touch with us!

>
> In OpenGRASP we  use COLLADA 1.5 as the file format to store robot models and scenarios. We have addressed several COLLADA related aspects.

> * Specification of robotic specific tags for COLLADA 1.5 ->  importer/exporter on OpenRAVE
>
> One feature of the OpenGRASP project is the extension of the COLLADA v1.5 format using the available mechanism to add user-defined content to the files. In cooperation with the developers of OpenRAVE, this idea evolved to provide definitions for sensors, more complex definitions of manipulators and grippers, and actuator models in the future. Some of these extensions can be found on the OpenRAVE homepage, and a more detailed description as well as the opportunity to discuss the extensions will be installed on our OpenGRASP project page.

I slightly differ with Herman here: I think it's a good idea
1/ to rely on Collada 1.5
2/ To use the built-in extension mechanisms (especially since the 
'technique' keyword allows several profiles to co-exist)

The proposal on the OpenRave website 
(http://openrave.programmingvision.com/wiki/index.php/Format:COLLADA) 
looks interesting. We need to look at it in details to see how it could 
match the MORSE abstractions.

We plan anyhow to use a standard, ASCII based file format for MORSE 
simulation assets, and Collada is today the best option.

> To know more about this you can contact: puche AT icc.uji.es
>
> * Blender COLLADA 1.5 importer/exporter
>
> A blender (2.4) script for importing/exporting COLLADA 1.5 has been developed. The export of valid models has been completed a while ago and, currently, we finished the work on an initial import of the models we have created. Therefore, the existing code of the version 1.4 plug-in (from Illusoft) has been further extended. We have also investigated the possibility of replacing large parts this code basis by a parser that has been created automatically from COLLADA's scheme definition. That way, the code can be cleaned up and enable a stand alone application. COLLADA support is still closely connected to the editing (i.e., requires the Robot Editor) as it is using additional information stored in the property fields of the armature objects, rather than the pure geometry. However, it could be separated from the robot editing interface for the use in different projects with little effort.
>
> So, we would like to encourage the integration of this work in other projects (OpenCOLLADA, ..) and any help on modularization, debugging/testing, etc. is highly welcome.

Very good. Do you plan to port it to Blender 2.5? API have changed a lot 
and Blender 2.4x isn't supported anymore: it would be a pity to loose 
all the good work you did!

Where can we get the source code? do you use VCS that allow easy 
contribution like git or mercurial? (via Github or Bitbucket?)

>
> Contact: stefan.ulbrich AT kit.edu
>
> * Blender Robot Editor plug-in
>
> This feature aims to facilitate the creation of robot models for scientific applications. Blender is difficult to master, and the available mechanisms for the definition of kinematics lack a robotics focus. This plug-in lets one build up a kinematic tree and connect it to the geometries in a way that is more familiar to robotic scientists. Together with the powerful modeling capabilities and the various option for importing geometries that blender offers, this plug-in helps to easily create robot models usable in Simulation.
> the import and export of COLLADA v1.5 is currently tightly coupled with this plug-in. Currently, it runs only on blender 2.48/2.49.

This sounds very interesting as well. On the website, it's a bit 
difficult to understand how it work. Cold you put some videos to better 
understand?

And same question: do you plan to port it to Blender 2.5 ?

>
> For questions please contact: stefan.ulbrich AT kit.edu
>
> It's important that you are aware that this a work still on development and in a beta state. You are more than welcome to download, test , use it, and contribute to its development. We will still be pushing on its development and the feedback from users and collaborators can be of interest for all of us.
>
> Of course, we are open to establish future collaborations.

It's definitely something we would support!
Maybe we should organize an "OpenGrasp/OpenRave - MORSE" event to 
present the work we did on both side, and see where we can cooperate 
(definition of standards, libraries of assets, ...)

Best regards!
Severin

-- 
           Séverin Lemaignan - severin.lemaignan at laas.fr
   [00]    PhD student on Cognitive Robotics
  /|__|\   LAAS-CNRS - RIS group / Technische Uni München - IAS group
    ''     +33561337844 / +498928917780
           http://www.laas.fr/~slemaign