Gazebo URDF image textures

This ROS package gives an example how to add image textures to URDF files so that they are visible in Gazebo.
Below you can find some images of the final result.

Usage

Add the package to a workspace and build it (catkin_make).
Then you can start Gazebo and spawn the cubes.

Launch gazebo

Source your workspace!

source devel/setup.bash

Launch Gazebo

roslaunch gazebo_ros empty_world.launch

Spawn the cubes

Source your workspace.

source devel/setup.bash

Spawn simple cube 1.

roslaunch example_models spawn_simple_cube1.launch

Spawn simple cube 2.

roslaunch example_models spawn_simple_cube2.launch

Spawn the aruco cube.

roslaunch example_models spawn_aruco_cube.launch

Spawn the aruco cube with another texture.
This can be done via the use_texture_... parameters.
One of the textures is used by default so we set it to false and set the other texture to true.

roslaunch example_models spawn_aruco_cube.launch use_texture_0to15:=false use_texture_16to31:=true

To be able to spawn multiple aruco markers at the same time, each one needs a different model name.
It can be provided in the following way:

roslaunch example_models spawn_aruco_cube.launch model_name:=aruco_cube2

How to

To add an image texture to a URDF link, do the following:

Create this folder structure in your package with the robot description:

package_root_folder/media/materials/scripts/
package_root_folder/media/materials/textures/

In the scripts folder you create a your_model.material file and put this in it:

material YourTexture{
technique
{
    pass
    {
        texture_unit
        {
            texture your_image.jpg
            scale 1 1
        }
    }   
}
}

You can add multiple textures in this file.

In the textures folder put your_image.jpg.

In the package.xml of your package add this:

<exec_depend>gazebo_ros</exec_depend>
<export>    
    <gazebo_ros gazebo_media_path="${prefix}"/>                             
</export>

Create a your_model.urdf.xacro and a your_model.gazebo.xacro file (note: it does NOT have to be the same name as your .material file). In the your_model.urdf.xacro file create your urdf. Also include the your_model.gazebo.xacro file with

<xacro:include filename="$(find your_package_name)/path/to/model.gazebo.xacro"/>

To use the texture on a link now, add the following within your your_model.gazebo.xacro file:

<gazebo reference="your_urdf_link_name">
    <material>YourTexture</material>
</gazebo>

Note that YourTexture is the name of the material you gave it in the .material file, not the name of the .material file itself.

Further notes

• It might be necessary to restart gazebo / the ROS core if applying the texture does not work.

• Be sure that the terminal with which you launch gazebo (e.g. with roslaunch gazebo_ros empty_world.launch) has your workspace sourced (source devel/setup.bash).

• For more details on e.g. the launch files or the URDF structure have a look at the source code.

• It was also tested to add the textures directly into .DAE files which also worked.
  It resulted in worse reflective behavior though which made the textures less bright.
  There might be a possibility to fix this behavior but I didn't find it.

• This was tested with ROS Noetic and Gazebo 11.5.1 but might also work with other ROS / Gazebo versions.

• The Aruco markers were created with this awesome website (https://chev.me/arucogen/) and then stitched together to the 4-marker images.