`Root` option does not work when exportedFrames are rigidly connected to it

[FabioBergonti]

Hi!
I'm exporting an assembly with two exportedFrames (l_ankle_spherical_parent_1 and l_ankle_spherical_parent_2) that are rigidly connected to the intended root link (l_lower_leg). However, when the URDF is generated, the first link is unexpectedly set to one of the exported frames (l_ankle_spherical_parent_1), instead of the one I selected in the yaml (l_lower_leg).

Here is an excerpt of the generated URDF:

<?xml version="1.0"?>
<robot name="test">
  <link name="l_ankle_spherical_parent_1"/>
  <joint name="l_ankle_spherical_parent_1_fixed_joint" type="fixed">
    <origin xyz="0 -0.043000000000000003 1.1389215232070394e-17" rpy="0 -0 0"/>
    <parent link="l_ankle_spherical_parent_1"/>
    <child link="l_lower_leg"/>
  </joint>

If I remove the exportedFrames, the selected root link (l_lower_leg) is correctly used as the root in the URDF, as expected.

I've attached the files used for both tests for your reference.

Tested with:

• Creo 9.0.2.0
• creo2urdf v0.5.11

Let me know if I can provide more details to help reproduce the issue.

[Nicogene]

Hi @FabioBergonti! Can you post also the yaml ? I will try to reproduce it with the two bars assembly

[traversaro]

This sounds related to the setting of the iDynTree::ModelExporterOptions::exportFirstBaseLinkAdditionalFrameAsFakeURDFBase parameter, that was an old workaround for a still present issue in KDL/ROS (ros/kdl_parser#27, ros/robot_model#6), see the issue robotology/idyntree#1201 .

As this seems confusing in the creo2urdf world, probably we can just set it to false in creo2urdf ?

[Nicogene]

This sounds related to the setting of the iDynTree::ModelExporterOptions::exportFirstBaseLinkAdditionalFrameAsFakeURDFBase parameter, that was an old workaround for a still present issue in KDL/ROS (ros/kdl_parser#27, ros/robot_model#6), see the issue robotology/idyntree#1201 .

As this seems confusing in the creo2urdf world, probably we can just set it to false in creo2urdf ?

Probably I forgot to do set exportFirstBaseLinkAdditionalFrameAsFakeURDFBase to false, in order to check this kind of behaviour a unit test would be of great help:

• Ad unit test in the CI #141

[FabioBergonti]

Hi @FabioBergonti! Can you post also the yaml ? I will try to reproduce it with the two bars assembly

Here it is

# Robot name
robotName: test

# Model base origin
root: l_lower_leg
originXYZ: [0.0, 0.0, 0.80]
originRPY: [0.0, 0.0, 0.0]

# Meshes options
scale: [0.001, 0.001, 0.001]
filenameformat: "package://meshes/simmechanics/%s.stl"
epsilon: 2e-4
exportMeshes: Yes

forcelowercase: Yes

rename:
  # left leg
  L_LOWER_LEG: l_lower_leg
  L_ANKLE_1: l_ankle_1
  L_ANKLE_2: l_ankle_2
  L_ANKLE_CROSS_1: l_ankle_cross_1
  L_ANKLE_CROSS_2: l_ankle_cross_2
  L_ANKLE_ACTUATOR_ROD_1: l_ankle_actuator_rod_1
  L_ANKLE_ACTUATOR_ROD_2: l_ankle_actuator_rod_2
  L_ANKLE_ACTUATOR_CASE_1: l_ankle_actuator_case_1
  L_ANKLE_ACTUATOR_CASE_2: l_ankle_actuator_case_2
  L_LOWER_LEG--L_ANKLE_1: l_ankle_pitch
  L_ANKLE_1--L_ANKLE_2: l_ankle_roll
  L_ANKLE_2--L_ANKLE_CROSS_1: l_ankle_cross_1_roll
  L_ANKLE_CROSS_1--L_ANKLE_ACTUATOR_ROD_1: l_ankle_cross_1_pitch
  L_ANKLE_ACTUATOR_ROD_1--L_ANKLE_ACTUATOR_CASE_1: l_ankle_prismatic_1
  L_ANKLE_2--L_ANKLE_CROSS_2: l_ankle_cross_2_roll
  L_ANKLE_CROSS_2--L_ANKLE_ACTUATOR_ROD_2: l_ankle_cross_2_pitch
  L_ANKLE_ACTUATOR_ROD_2--L_ANKLE_ACTUATOR_CASE_2: l_ankle_prismatic_2

exportAllUseradded: No

exportedFrames:
  - frameName: SCSYS_L_SPHERICAL_P_1
    frameReferenceLink: l_lower_leg
    exportedFrameName: l_ankle_spherical_parent_1
  - frameName: SCSYS_L_SPHERICAL_P_2
    frameReferenceLink: l_lower_leg
    exportedFrameName: l_ankle_spherical_parent_2

[FabioBergonti]

I tested the new release https://github.com/icub-tech-iit/creo2urdf/releases/tag/v0.5.12 and the problem disappeared!
Thanks @Nicogene @traversaro!

GitHub

Release v0.5.12 · icub-tech-iit/creo2urdf

What's Changed

Add vcpkg version in the documentation by @Nicogene in #144
Set iDynTree::ModelExporterOptions::exportFirstBaseLinkAdditionalFrameAsFakeURDFBase to false by default and expose it as...