[ros-users] Weirdness in URDF tutorials

[Björn Giesler]

Hi,

Addendum: My logs had the message 

ERROR: cannot launch node of type [robot_state_publisher/state_publisher]: Cannot locate node of type [state_publisher] in package [robot_state_publisher]

because robot_state_publisher hadn't been built yet. It seems after doing "rosmake robot_state_publisher state_publisher", everything is the way it should be -- now I still need to figure out why...

Regards,
Björn

Am 28.12.2010 um 17:21 schrieb Björn Giesler:

> Hi,
> 
> I'm trying to create a URDF model for my robot, which happens to be an R2-D2 replica so I was thrilled to find the wiki contains a series of tutorials that create a R2-D2 URDF. I'm trying to follow the tutorial on my robot's computer, a Zotac Zbox (NVIDIA ION-based) which I'm connecting to via VNC.
> 
> Is it possible that those tutorials are outdated and the URDF syntax and semantics have changed? It seems that transforms and materials don't behave the way they should.
> 
> This is how the second tutorial step should look like according to the wiki:
> 
> <PastedGraphic-2.tiff>
> 
> and this is how it looks on my machine:
> 
> <PastedGraphic-3.tiff>
> 
> Notice that the cylinder is OK, but the second shape (a .6x.2x.1 box) is rotated and also white. The URDF file I used is unmodified from urdf_tutorial, and its text is exactly as posted in the wiki.
> 
> The first thing I noticed was that the coordinate assignment looks off causing the box to be higher than wide instead of vice versa. So I tried to just put a couple of colored boxes in the x, y, and z directions to see what the proper assignment was. I got as far as one box, the URDF file is this:
> 
> <?xml version="1.0"?>
> <robot name="R2-D2">
>  <link name="base_link">
>    <visual>
>      <geometry>
> 	<cylinder length="0.6" radius="0.2"/>
>      </geometry>
>      <material name="white"><color rgba="1 1 1 1"/></material>
>    </visual>
>  </link>
> 
>  <link name="redbox">
>    <visual>
>      <geometry>
> 	<box size=".1 .1 .1"/>
>      </geometry>
>      <origin xyz="1 0 0"/>
>      <material name="red">
> 	<color rgba="255 0 0 0.5"/>
>      </material>
>    </visual>
>  </link>
> 
>  <joint name="base_to_redbox" type="fixed">
>    <parent link="base_link"/>
>    <child link="redbox"/>
>  </joint>
> </robot>
> 
> ...so it's a red box at xyz="1 0 0". This is how it looks like:
> 
> <PastedGraphic-4.tiff>
> 
> So the box is there, but it's not red... 
> 
> Can anyone tell me what's going on here?
> 
> Thanks a lot in advance,
> Björn
> -- 
> Björn Giesler
> bjoern at giesler.de
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-- 
Björn Giesler
bjoern at giesler.de
Verschlüssel Deine Emails -- oder schreibst Du Deine Briefe außen auf den Umschlag?
Meinen Schlüssel findest Du auf http://giesler.biz/~bjoern/downloads/bg.asc -- schick mir Deinen!
Mehr Informationen findest Du auf http://www.gnupg.org/index.de.html