We have floor plan (.png file) for one floor of our office building and we'd like to "extrude" the black cells in the image to make a kind of simple mesh for use in Gazebo. In other words, I'd like to turn the black lines into walls of a given height and then export the result as a Collada or STL mesh. Does anyone know of a tool that could do this automatically? I'm aware of Gazebo's ability to import a floor plan but then building the walls is a manual process. I've looked at Meshlab and Blender but so far I cannot see a way to do what I need.

Thanks! patrick

Edit 1

Thanks to the answer below, I created a test world file like the the one below. However, my floor plan is not showing up in Gazebo regardless of the values I set for scale, height, granularity and threshold. Does anyone have any suggestions or examples? Also, I am using Gazebo 2.2 under ROS Indigo.

test.world:

<?xml version="1.0"?>
<sdf version="1.4">
  <world name="default">
    <include>
      <uri>model://ground_plane</uri>
    </include>
    <include>
      <uri>model://sun</uri>
    </include>
    <model name="my_mesh">
      <pose>0 0 0  0 0 0</pose>
      <static>true</static>
      <link name="body">
        <visual name="visual">
        <geometry>
          <image>
            <uri>file://home/patrick/Dropbox/Robotics/ros/jackrabbot_testing/jr1_gazebo/models/gates_1/floor_plan/gates_1_floorplan_edited.png</uri>
            <scale>1</scale>
            <height>1</height>
            <threshold>0</threshold>
            <granularity>10</granularity>
          </image>
         </geometry>
        </visual>
      </link>
    </model>
  </world>
</sdf>