Adding visuals

Overview

This tutorial describes how to import 3D meshes into Gazebo to increase the visual fidelity of your model. Continuing with our example, we'll attach a 3D mesh to our turtle, making it look much better.

Related tutorials

Importing a Mesh to Fuel

The next tutorials, although still relevant, are from an older version of Gazebo and some details might be different than the current versions:

https://classic.gazebosim.org/tutorials?tut=import_mesh&cat=build_robot https://classic.gazebosim.org/tutorials?cat=guided_i&tut=guided_i2

What is a visual?

The visual element specifies the shape used by the rendering engine. For most use cases the collision and visual elements are the same. The most common use for different collision and visual elements is to have a simplified collision element paired with a visual element that uses a complex mesh. This will help improve performance.

SDF supports the notion of visual as described here.

From our previous tutorial, the turtle visual is a cylinder. Let's use a COLLADA mesh instead.

Model directory structure

Gazebo has defined a model directory structure that supports stand-alone models, and the ability to share models via an online model database. Review this tutorial for more information.

Another benefit of Gazebo's model structure is that it conveniently organizes resources, such as mesh files, required by the model.

my_turtle
├── materials               Directory for textures
    └── textures
├── meshes                  Directory for mesh files such as COLLADA, STL, and Wavefront OBJ files
├── thumbnails              Directory for preview images on Fuel
├── model.config            Meta data about the model
└── model.sdf               SDF description of the model

Create the directories to add the mesh and its texture:

mkdir -p ~/gazebo_maritime/models/my_turtle/meshes
mkdir -p ~/gazebo_maritime/models/my_turtle/materials/textures

Next, download the COLLADA mesh and its texture.

wget https://raw.githubusercontent.com/gazebosim/gz-sim/gz-sim8/tutorials/files/adding_visuals/turtle.dae -O ~/gazebo_maritime/models/my_turtle/meshes/turtle.dae
wget https://raw.githubusercontent.com/gazebosim/gz-sim/gz-sim8/tutorials/files/adding_visuals/Turtle_BaseColor.png -O ~/gazebo_maritime/models/my_turtle/materials/textures/Turtle_BaseColor.png

Now, let's edit our model.sdf to use the new mesh as our visual.

<?xml version="1.0" ?>
<sdf version="1.6">
  <model name="turtle">
    <static>true</static>
    <link name="base_link">
 
      <inertial>
        <pose>0 0 0 0 0 0</pose>
        <mass>10</mass>
        <inertia>
          <ixx>0.35032999999999995</ixx>
          <ixy>0</ixy>
          <ixz>0</ixz>
          <iyy>0.35032999999999995</iyy>
          <iyz>0</iyz>
          <izz>0.61250000000000006</izz>
        </inertia>
      </inertial>
 
      <collision name='collision'>
        <pose>0 0 0 0 0 0</pose>
        <geometry>
          <box>
            <size>1 1 0.009948450858321252</size>
          </box>
        </geometry>
      </collision>
 
      <visual name="visual">
        <geometry>
          <mesh>
            <uri>meshes/turtle.dae</uri>
          </mesh>
        </geometry>
      </visual>
 
    </link>
  </model>
</sdf>

Load your model in Gazebo

Launch Gazebo and load our model:

gz sim ~/gazebo_maritime/models/my_turtle/model.sdf

You should see your model visualized as a mesh now!