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How many vertices can Gazebo (ODE) handle?

asked 2019-02-11 14:57:53 -0500

mehdi gravatar image

updated 2019-02-11 14:59:39 -0500

I have been trying to load a mesh in gazebo (Meshlab shows it has some 1.5 million vertices), it takes some time but Gazebo can make it but doesn't display everything inside the mesh as some parts are missing.

When I then spawn a simple object (bowl with 600 vertices) on top of one part of the big mesh (a ring shaped table) it just sinks inside the mesh while slowing down until coming out from the other side. I expect it to just stand there as it should when you pot a bowl on a surface. I tried reducing the number of vertices to 200000 with Meshlab but nothing changed.

I couldn't find any documentation about such behavior. I checked the inertia, the center of mass, the overlap between collision and visual model and everything seems fine. I also tried bullet, the behavior was a bit different and the bowl started flying around, ending up on the floor after few minutes. Are there any other details that I am missing?

I am working with Gazebo 9.0.0 and collada meshes that I export from Blender.

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answered 2019-02-18 06:15:05 -0500

ce_guy gravatar image

For the collision problem I think you have just specified a visual tag for your collada mesh but forgot to set a collision tag.

It has to look like this

<model name='test'>
  <link name='test_link'>

    <collision name='collision'>
      <geometry>
        <mesh>
          <uri>model://test_pkg/meshes/test_mesh.dae</uri>
        </mesh>
      </geometry>
    </collision>

    <visual name='visual'>
      <geometry>
        <mesh>
          <uri>model://test_pkg/meshes/test_mesh.dae</uri>
        </mesh>
      </geometry>
    </visual>

  </link>
</model>

For your other problem I don't have an answer. I don't really know how many vertices can be displayed. I always simplify my meshes in Meshlab. You could use a very nice mesh for visual and a simplified one for collision.

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The geometry of the collision part has been set correctly. If I replace the mesh of the bowl by a cylinder defined directly in Gazebo, it works like a charm, but you can't really simulate the bowl containing some stuff if its collision model is a full cylinder.

mehdi gravatar imagemehdi ( 2019-02-25 14:04:09 -0500 )edit

I am using a 3D outdoor map (.obj file) with a vehicle model (all parts of the vehicle have complex collision models (.stl files)) and it does not fall through the map. Are you using the same collada files for visual and collision when the bowl falls through the desk? My map has 1.4 million vertices (so it should be possible with your model).

ce_guy gravatar imagece_guy ( 2019-02-28 09:12:57 -0500 )edit

yes using the same file for visual and collision. I am thinking about writing a macro to generate a bowl using a cylindrical base surrounded by vertical rectangular boxes. That should do it

mehdi gravatar imagemehdi ( 2019-02-28 09:22:53 -0500 )edit

Have you tested if it happens with other self modelled objects too (that they drop through the table)? Does the bowl just drop through the table or through the ground plane as well?

ce_guy gravatar imagece_guy ( 2019-02-28 09:33:28 -0500 )edit
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Asked: 2019-02-11 14:57:53 -0500

Seen: 261 times

Last updated: Feb 18