Added Mesh Moment of Inertia Calculator

[jasmeet0915]

🎉 New feature

Based on this proposal.

Summary

• The PR implements a Moment of Inertia Calculator based on the method described in this document.
• The calculator works using the callback-based API from the sdformat made in this PR.

Demo & Usage Example

Demo 1: This demo shows the automatic inertia calculation feature on a rubber ducky model which is a non-convex mesh. On the left, we have the rubber ducky mesh with automatic calculations enabled and on the right, the mesh uses the default values.

Note: The inertial values are due to the scale of the mesh. You can see the banana for scale in between the 2 ducks. A density value for the duck was used which was calculated by using the mass and volume data of the duck found online.

Note: The voxel_size inertia param given in the snippet below is just for showing how the <auto_inertia_params> element could be used. This is not actually used by the calculator since we are not using a voxelization-based calculator.

SDF snippet for the duck mesh with auto inertial

<?xml version="1.0" ?>
<sdf version="1.6">
<model name="duck">
  <link name="duck_link">
    <pose>0 0 0 0 0 0</pose>
    <inertial auto="true" />
    <collision name="duck_collision">
    	<pose>0 0 0 0 0 0</pose>
      <density>111.8</density>
      <auto_inertia_params>
        <gz:voxel_size>0.01</gz:voxel_size>
      </auto_inertia_params>
      <geometry>
        <mesh>
          <uri>meshes/duck_collider.dae</uri>
        </mesh>
      </geometry>
    </collision>
    <visual name="duck_visual">
      <pose>0 0 0 0 0 0</pose>
      <geometry>
        <mesh>
          <uri>meshes/duck.dae</uri>
        </mesh>
      </geometry>
    </visual>
  </link>
  <static>true</static>
</model>
</sdf>

Demo 2: This demo shows 2 cylinders: One using a Collada cylinder mesh (right) and the other made using the <cylinder> geometry from SDF (left).

Both use <inertial auto="true" /> and we can see that the inertia values for both come up to be almost the same (within 0.005 tolerance). The mesh cylinder uses the mesh inertia calculator added to gz-sim and is used with libsdformat using the callback-based API.

SDF snippet for the mesh cylinder

  <model name="cylinder_dae">
    <pose>4 4 1 0 0 0</pose>
    <link name="cylinder_dae">
      <pose>0 0 0 0 0 0</pose>
      <inertial auto="false" />
      <collision name="cylinder_collision">
        <density>1240.0</density>
        <auto_inertia_params>
          <gz:voxel_size>0.01</gz:voxel_size>
        </auto_inertia_params>
        <geometry>
          <mesh>
            <uri>cylinder_dae/meshes/cylinder.dae</uri>
          </mesh>
        </geometry>
      </collision>
      <visual name="cylinder_visual">
        <pose>0 0 0 0 0 0</pose>
        <geometry>
          <mesh>
            <uri>cylinder_dae/meshes/cylinder.dae</uri>
          </mesh>
        </geometry>
      </visual>
    </link>
    <static>true</static>
  </model>

TODO:

• Update return type for Inertia Calculator to optional inertial object
• Add Tests

Checklist

• Signed all commits for DCO
• Added tests
• Added example and/or tutorial
• Updated documentation (as needed)
• Updated migration guide (as needed)
• Consider updating Python bindings (if the library has them)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
• While waiting for a review on your PR, please help review another open pull request to support the maintainers

Note to maintainers: Remember to use Squash-Merge and edit the commit message to match the pull request summary while retaining Signed-off-by messages.

[ahcorde]

some lines are more than 100 characters, review style too

Is there any reason to include the implementation in the hpp ? I think you should move the implementation to a cpp file.

Add some tests too

and add some tests

[azeey]

Can you merge from main. Some of the changes in this PR are already in main.

[jasmeet0915]

@ahcorde

some lines are more than 100 characters, review style too

Corrected the style and completed codecheck in 3fc1587

Is there any reason to include the implementation in the hpp ? I think you should move the implementation to a cpp file.

I have removed implementation from the header file and added it to a separate source file.

[jasmeet0915]

@azeey I have merged main in 40c5100

[iche033]

Maybe add a test for the MeshInertiaCalculator class?

[jasmeet0915]

@iche033 I have added an integration test for the class in a53f441

[iche033]

hmm there seems to be more test failures than usual

[iche033]

merging #2105 first

[jasmeet0915]

hmm there seems to be more test failures than usual

@iche033 the test failures were coming due to not using the ParserConfig::GlobalConfig() before registering the mesh inertia calculator and calling Root::Load() in Sever.cc.This was causing the tests using fuel resources to not be able to resolve the URIs. This should be fixed now in 7864454

[codecov]

Codecov Report

Merging #2061 (0b95e6f) into gz-sim8 (8e7f612) will increase coverage by 0.08%.
The diff coverage is 91.89%.

❗ Current head 0b95e6f differs from pull request most recent head 7b1dbe5. Consider uploading reports for the commit 7b1dbe5 to get more accurate results

@@             Coverage Diff             @@
##           gz-sim8    #2061      +/-   ##
===========================================
+ Coverage    65.34%   65.43%   +0.08%     
===========================================
  Files          322      323       +1     
  Lines        30554    30699     +145     
===========================================
+ Hits         19967    20088     +121     
- Misses       10587    10611      +24     

Files Changed	Coverage Δ
src/Server.cc	87.07% <80.00%> (-0.06%)	⬇️
src/MeshInertiaCalculator.cc	92.75% <92.75%> (ø)

... and 2 files with indirect coverage changes

Feedback addressed