[ros-users] SolidWorks to URDF

[David Lu!!]

> We have complicated SolidWorks model and often current tutorials fail in
> different reasons. Some reasons are obvious like using Estonian words
> with characters like õäö in model etc.
I've replicated this error using your model. Please submit it a bug to
remind me to try to fix it.
http://sourceforge.net/tracker/?group_id=261576&atid=1333666
In the meantime, your solution of just replacing the characters
manually will have to suffice.

> 1. After changing SolidWorks model sometime conversion gives incorrect
> URDF file.

It would be helpful to know how it is incorrect. I am guessing that it
is a matter of getting the configuration file correct, but if its
something else, that would be useful to know.

> I currently think this is model root is wrong and I need to
> modify it in YAML config file of simmechanics_to_urdf. I clearly
> misunderstand something and cannot get it working.

The root node refers to the piece of your model that will be the root
element of your URDF (i.e. the piece with no parent). If you are
unfamiliar, take a look at the structure of URDF files and look at the
graph vs. tree discussion in the simmechanics_to_urdf wiki page.

> Please someone provide working example :)
This package was written last summer as part of an internship I did.
As such, I have limited access to non-classified working examples.
However, knowing that someone is attempting to use my code (which I
was not convinced would be the case) provides slightly more motivation
to get that done.

> 3. This is something I have not yet looked deep but our model have lot
> of moving parts and I need to make them move around in RVIZ. I cannot
> find good tutorial or explanation how things like gears should work in
> ROS. If I rotate one of them, can all others rotate automatically? We
> have about hundred moving parts and they are all driven by two motors
> only. What is the good way?
When building my own URDF, I found that sufficiently complicated
models with lots of dependent parts are problematic using current ROS
formalisms.
See: http://ros-users.122217.n3.nabble.com/The-Limitations-of-URDF-td1031473.html
My solution was to link joints together when I publish JointState
messages using
http://www.ros.org/wiki/joint_state_publisher

There is also some black magic surrounding the urdf mimic tag that may
be useful in this context.
http://ros-users.122217.n3.nabble.com/urdf-joint-mimic-tag-td2208605.html