Technique for spawning and deleting large number of models quickly

edit

We are trying to run some tests in simulation. The procedures are roughly as follows

1. Spawn a large number of models (currently simple spheres) at random positions
2. Run some tests
3. Delete the spawned models so we return to the initial state
4. Repeat

Currently, I am using the ros services /gazebo/spawn_sdf_model and /gazebo/delete_model to spawn and delete models respectively.

The problem is, spawning a single model takes 200ms, deleting a single model takes 400ms. Since I need to do this many times, this takes an extremely long time.

Am I doing something wrong that it takes so long to spawn a simple sphere? Is are there better ways to spawn and delete large number of models, e.g. bulk spawn, or reload the environment?

I am currently running on a system without a GPU but with a fairly powerful CPU and CPU usage isn't maxed out. Would using a GPU help?

The sdf file is as simple as it gets

<?xml version="1.0" ?>
<sdf version="1.5">
  <model name="tiny sphere">
    <static>true</static>
    <link name="link">
      <pose>0 0 0 0 0 0</pose>
      <inertial>
        <mass>1.0</mass>
      </inertial>

      <collision name="collision">
        <geometry>
          <sphere>
            <radius>0.01</radius>
          </sphere>
        </geometry>
      </collision>

      <visual name="visual">
        <geometry>
          <sphere>
            <radius>0.01</radius>
          </sphere>
        </geometry>
      </visual>

    </link>
  </model>
</sdf>