Using the scale option for the physics engine as well makes the helicopter model stable. Otherwise it just seemed to drift away even though it was initialized at z = 0. Maybe it was too large and the body weight assigned through box_geom was too small for it.

I have placed the "gazelle.material" file at the right location. I just get a red helicopter.

I get the message:

Gazebo Path[/usr/local/share/gazebo]
Ogre Path[/usr/local/lib/OGRE]
  Creating GUI:
        Type[fltk] Pos[0 0] Size[800 600]
creating /tmp/gazebo-hasan-0
creating /tmp/gazebo-hasan-0/simulation.default 112 688
  Unable to get Material[gazelle] for Geometry[SceneRoot_VISUAL_402_VISUAL_0_VISUAL_1_VISUAL_0. Object will appear white


On Mon, Feb 18, 2008 at 8:43 AM, Nate Koenig <nkoenig@usc.edu> wrote:

You have applied the <scale> option only to the visual. This will
cause the helicopter to be visually smaller, but the physics engine
will think it's much bigger. You should apply the scale in both the
geom and the visual.

The helicopter model will fall automatically, since gravity acts on
the model. You'll have to write a special controller to make the
helicopter stay aloft.

The material file seems to work for me. Make sure you copied it into
the correct location:


On Feb 4, 2008 2:58 AM, Vaibhav Ghadiok <vaibhavghadiok@gmail.com> wrote:
> hi
> I have a bit of a problem with the helicopter model. I am using  SVN version
> 233 of Gazebo.
> My world file part of the model declaration is:
> <model:physical name="helicopter">
>  <xyz>3 3 0</xyz>
>   <rpy>0 0 0</rpy>
>   <static>false</static>
>    <body:trimesh name="gazelle_body">
>         <geom:box name="box1_geom">
>         <size>1 1 1</size>
>          <mass>1.0</mass>
>         </geom:box>
>          <geom:trimesh name="gazelle_geom">
>                 <mesh>gazelle.mesh</mesh>
>                  <material>gazellle</material>
>                <visual>
>                    <scale>0.15 0.15 0.15</scale>
>                    <mesh>gazelle.mesh</mesh>
>                     <material>gazelle</material>
>              </visual>
>         </geom:trimesh>
>     </body:trimesh>
> </model:physical>
> I have added the "gazelle.mesh" file in the
> "/usr/local/share/gazebo/Media/models/". and the "gazelle.material" file in
> the "/usr/local/share/gazebo/Media/materials/scripts/".
>  I have attached these files to the post.
> I am facing two problems.
> 1.One is the Helicopter seems to fall off the sky and then never seems to
> settle on the ground and it keeps bobbing around. It is fine if I make
> static =false. The same behavior is seen even if geom box is removed. I had
> finally like to give some kind of body to the helicopter for collision
> detection.
> 2.The second problem is that it is not able to find the gazelle material. I
> get a message stating that the helicopter will be displayed white but
> instead it is displayed as red with black propellers.
> Cheers
>  Vaibhav
> --
> http://guidance.aero.iisc.ernet.in/vaibhav
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