Hi everyone

I want to create a custom OGRE material file, store it in my ROS Indigo package, and have my robot's visual in Gazebo use these materials.

I don't want to use SDF (I know how to; in fact, I learned SDF before URDF).

Here's what I tried and the results I got:

1. Using Gazebo's built in materials work.

   <gazebo reference="…">
       <material>Gazebo/Yellow</material>
   </gazebo>
   

2. Adding materials to Gazebo's built in materials file at /usr/share/gazebo-2.2/media/materials/scripts/gazebo.material also works.

3. This didn't work. It's for ROS Fuerte and Gazebo 1, so I had to make some changes:

   1. roscreate-pkg gazebo_tutorials std_msgs rospy roscpp gazebo failed because ERROR: dependency [gazebo] cannot be found. I installed through apt-get every package that had gazebo in the name, but that didn't fix it. So, instead, I replaced gazebo by all packages returned by rospack list that started with gazebo. Only after the package was created that I realized it was the command to generate the old package format. This and this pages confirm that rospack find gazebo used to work in the past and doesn't anymore. So I created a new package and replaced the <depend> tags by <build_depend>, <buildtool_depend> and <run_depend>.
   2. I tried with <gazebo gazebo_media_path="${prefix}" /> but, when launching the package, Warning [Visual.cc:819] Unable to get Material[…] for Geometry[…. Object will appear white. Then I replaced ${prefix} by the full path to where my ….material file was located; same result.

4. The first snippet from the answer to this question results in Warning [Visual.cc:819] Unable to get Material[script] for Geometry[…. Object will appear white. Note it says script instead of the material name. I tried several variations for <uri>'s argument.

5. This confirmed a suspicion that the ….material file must be inside a Media folder, so I'm testing with and without it.

6. This led me

   1. here, but adding the <env> tag to the launch file also didn't work. Because find gazebo doesn't work anymore, I'm using "$GAZEBO_RESOURCE_PATH:$(find …)". I'm not certain if it makes sense.
   2. and here. There's two ….material files and one ….urdf file that uses one of those materials, but this file isn't used anywhere. Also, the syntax is strange. It says <material>b21.material</material>, which is the name of the file, but the materials defined there are named b21_base_dark and b21_base_blue. These names aren't used anywhere. I also tried to place my ….material file in the full Media/materials/scripts path as is used by this package. manifest.xml only confirms to me that "${prefix}" is correct, but I don't know what's the impact of not having the gazebo package anymore.

7. I don't mind using a colored Collada file if it worked. I applied random face colors with MeshLab. Mesh is still white. In RViz, it's a darker gray. Adding an <ambient> tag as per here makes no difference.

8. I tried ryan.delgizzi's answer below. The link appears as Orange instead of the expected olive green.

Please walk me through the steps necessary to make this work.

I've created a test package that incorporates all of these attempts.

Thanks in advance.

Update: I found out it works on Lunar while preparing the package above.

I still want to make it work in Indigo.

1. Does not require <export> or other tags on package.xml.

2. Requires the following on the ….launch file, if the ….material file is in the package root folder. Otherwise, complete the path to the ….material file.

   <env
       name="GAZEBO_RESOURCE_PATH"
       value="$GAZEBO_RESOURCE_PATH:$(find …)"
   />
   

3. Requires the following on the ….urdf files:

   <gazebo reference="…">
       <material>…/…</material>
   </gazebo>
   

Update: I added the tests that I made before preparing this package. I also fixed package.xml because I created the package in Lunar while it was meant to be for Indigo. And I also took a screenshot of what shows up in Gazebo in this most recent version. Yellow is a built in Gazebo color. Orange is the color I added to Gazebo's built in colors. Azure is the color I'm trying to apply to links. The last link (from item #8 of the first post) was added later and is not present in the image.

<?xml version="1.0"?>
<robot xmlns:xacro="http://ros.org/wiki/xacro">
  <xacro:macro name="material_olive_green">
  <visual>
    <material>
      <ambient>0.3137254 0.3254902 0.2352941 1</ambient>
      <diffuse>0.3137254 0.3254902 0.2352941 1</diffuse>
      <specular>0.1 0.1 0.1 1</specular>
      <emissive>0 0 0 0</emissive>
    </material>
  </visual>
</xacro:macro>
</robot>

<gazebo reference="${prefix}base_link">
  <xacro:material_olive_green />
  <turnGravityOff>true</turnGravityOff>
</gazebo>