Attach Meshes

Overview

Prerequisites: Make a mobile robot

Meshes can add realism to a model both visually and for sensors. This tutorial demonstrates how the user can use custom meshes to define how their model will appear in simulation.

Attach a Mesh as Visual

The most common use case for a mesh is to create a realistic looking visual.

Navigate to the my_robot directory
```
cd ~/.gazebo/models/my_robot
```
Open the model.sdf file using your favorite editor
```
gedit ~/.gazebo/models/my_robot/model.sdf
```

We'll add a mesh to the chassis visual. Find the visual with name=visual, which looks like:

    <visual name='visual'>
      <geometry>
        <box>
          <size>.4 .2 .1</size>
        </box>
      </geometry>
    </visual>

A mesh can come a file on disk, or from another model. In this example we'll use a mesh from the pioneer2dx model. Change the visual element to the following (but keep the the rest of the file intact):
```
    <visual name='visual'>
      <geometry>
        <mesh>
          <uri>model://pioneer2dx/meshes/chassis.dae</uri>
        </mesh>
      </geometry>
    </visual>
```
Look in your locally cached model database to see if you have the pioneer2dx model referenced by above <mesh> block:
```
ls -l ~/.gazebo/models/pioneer2dx/meshes/chassis.dae
```
If the mesh file does not exist, make Gazebo pull the model from the Model Database by spawning the Pioneer 2DX model at least once in gazebo (under Insert->http://gazebosim.org/models).

Or manually download the model files to your local cache:
```
cd ~/.gazebo/models
wget -q -R *index.html*,*.tar.gz --no-parent -r -x -nH http://models.gazebosim.org/pioneer2dx/
```
In Gazebo, drag the My Robot model in the world. The visual for the chassis will look like a pioneer2dx.
The chassis is obviously too big for our robot, so we need to scale the visual.

Modify the visual to have a scaling factor.

    <visual name='visual'>
      <geometry>
        <mesh>
          <uri>model://pioneer2dx/meshes/chassis.dae</uri>

          <scale>0.9 0.5 0.5</scale>

        </mesh>
      </geometry>
    </visual>

The visual is also a little too low (along the z-axis). Let's raise it up a little by specifying a pose for the visual:
```
    <visual name='visual'>
```
```
      <pose>0 0 0.05 0 0 0</pose>
```
```
      <geometry>
        <mesh>
          <uri>model://pioneer2dx/meshes/chassis.dae</uri>
          <scale>0.9 0.5 0.5</scale>
        </mesh>
      </geometry>
    </visual>
```
Note that at this point we have simply modified the <visual> elements of the robot, so the robot will look like a scaled down version of the Pioneer 2DX model through the GUI and to GPU based sensors such as camera, depth camera and GPU Lasers. Since we did not modify the <collision> elements in this model, the box geometry will still be used by the physics engine for collision dynamics and by CPU based ray sensors.

Try for yourself

Find and download a new mesh on 3D Warehouse. Make sure the mesh is in the Collada (.dae) format.
Put the mesh in the ~/.gazebo/models/my_robot/meshes, creating the meshes subdirectory if necessary
Use your new mesh on the robot, either as a replacement for the chassis, or as an additional <visual>.

Note: Materials (texture files such with extension like .png or .jpg), should be placed in ~/.gazebo/models/my_robot/materials/textures.

Next: Add a Sensor to a Robot

Attach Meshes

Table of Contents

Overview

Attach a Mesh as Visual

Further Reading

Try for yourself

Next