Collision and collada meshes

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I am using .dae meshes for my robot and it seems that when I define the collision tag using that mesh, objects can just go through and no collision is simulated. Why is that? example of my urdf

<link name="disk${index}">
  <visual>
    <geometry>
      <mesh filename="package://maru_simulation/meshes/disk.dae"/>
    </geometry>
    <origin xyz="0 0 -0.01" rpy="0 0 0"/>
  </visual>
<inertial>
  <mass value="0.01" />
  <inertia ixx="1.0" ixy="0.0" ixz="0.0"
  iyy="1.0" iyz="0.0"
  izz="1.0" />
</inertial>
  <collision>
    <geometry>
      <mesh filename="package://maru_simulation/meshes/disk.dae"/>
    </geometry>
    <origin xyz="0 0 -0.01" rpy="0 0 0"/>
  </collision>
</link>