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Problems working with .dae files

asked 2017-11-28 12:12:42 -0500

SteBisi gravatar image

updated 2017-11-29 04:08:26 -0500

gvdhoorn gravatar image

Hello everyone, I'm struggling with a urdf model to visualize in rviz, this is the file I've written so far:

<?xml version="1.0"?>
<robot name="bot2489">

  <material name="black">
    <color rgba = "0 0 0 1"/>

  <link name="base_link">
      <origin rpy="0.0 0 0" xyz="0 0 0"/>
      <material name="black"/>
        <mesh filename="package://bot2489_description/meshes/bot2489_body.dae"/>
      <origin rpy="0.0 0 0" xyz="0 0 0"/>
        <mesh filename="package://bot2489_description/meshes/bot2489_body.dae"/>

The problem is that when I launch it in rviz, using the urdf_tutorial display.launch file, nothing appears. In the "Global Status" section of the window there's a warning :

No tf data. Actual error: Fixed Frame [base_link] does not exist

It is weird, because the .dae file should be fine (is made with Rhino v5 and saved as .dae), and on the terminal, while loading the file, I get no errors. Can you please help me to understand what I'm doing wrong?

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Can you update your question text with the exact command that you use to start everything (ie: the one with display.launch) and include the complete output you see on the console after starting it?

gvdhoorn gravatar image gvdhoorn  ( 2017-11-29 04:10:22 -0500 )edit

If you posted your complete URDF, I think the issue is that you don't have any <joint> elements. Without a joint connecting two links, there is nothing for the robot_state_publisher to send on /tf. Try adding a link with only the name set, and a fixed joint connecting the two links

jarvisschultz gravatar image jarvisschultz  ( 2017-11-29 07:49:44 -0500 )edit

@jarvisschultz, I think it t could be also that, but I got the same error even after adding the joints. Ended up that the problem were the .dae files, that I created with rhino.I just had to export them to Blender as .3ds files and there export them as .dae files and everything worked

SteBisi gravatar image SteBisi  ( 2017-11-29 22:25:36 -0500 )edit

It would perhaps be good to see what the incompatibility is. Could you perhaps submit an issue to ros-visualization/rviz/issues with a minimal URDF and an example Collada file that shows this problem?

gvdhoorn gravatar image gvdhoorn  ( 2017-11-30 03:03:06 -0500 )edit

1 Answer

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answered 2017-11-28 21:15:32 -0500

avcx gravatar image

Try adding inertial before the <visual>,, this way

    <mass value="1.0" />
    <inertia ixx="1.0" ixy="0.0" ixz="0.0" iyy="1.0" iyz="0.0" izz="1.0" />

More accurate inertial can be from the CAD software itself. Also, often the mesh (*.dae or *.stl ) from CAD software will be in millimeters. So you might also need to scale the dimensions by 0.001 this way

<mesh filename="package://pkg_name/path/part.dae" scale="0.001 0.001 0.001"/>

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Thank you for the answer, I tried to do what you said but I still ave the same problem

SteBisi gravatar image SteBisi  ( 2017-11-29 04:04:19 -0500 )edit

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Asked: 2017-11-28 12:12:42 -0500

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Last updated: Nov 29 '17