Getting Rigid Body Error when starting simulation

Hi, I was working on the issac sim and following the tutorial of the documents provided by issac sim.

I’ve tried your tutorial step by step which corresponding link says:
https://docs.omniverse.nvidia.com/app_isaacsim/app_isaacsim/tutorial_ros2_drive_turtlebot.html#isaac-sim-app-tutorial-ros2-drive-turtlebot

After I put the turtlebot burger urdf file via import URDF, the error messages is keep occuring as below when I play the button.

2023-06-05 16:28:43 [2,144,520ms] [Warning] [omni.physx.plugin] The rigid body at /World/turtlebot3_waffle/base_footprint has a possibly invalid inertia tensor of {1.0, 1.0, 1.0} and a negative mass, small sphere approximated inertia was used. Either specify correct values in the mass properties, or add collider(s) to any shape(s) that you wish to automatically compute mass properties for. If you do not want the objects to collide, add colliders regardless then disable the ‘enable collision’ property.
2023-06-05 16:28:43 [2,144,520ms] [Warning] [omni.physx.plugin] The rigid body at /World/turtlebot3_waffle/camera_depth_frame has a possibly invalid inertia tensor of {1.0, 1.0, 1.0} and a negative mass, small sphere approximated inertia was used. Either specify correct values in the mass properties, or add collider(s) to any shape(s) that you wish to automatically compute mass properties for. If you do not want the objects to collide, add colliders regardless then disable the ‘enable collision’ property.
2023-06-05 16:28:43 [2,144,520ms] [Warning] [omni.physx.plugin] The rigid body at /World/turtlebot3_waffle/camera_depth_optical_frame has a possibly invalid inertia tensor of {1.0, 1.0, 1.0} and a negative mass, small sphere approximated inertia was used. Either specify correct values in the mass properties, or add collider(s) to any shape(s) that you wish to automatically compute mass properties for. If you do not want the objects to collide, add colliders regardless then disable the ‘enable collision’ property.
2023-06-05 16:28:43 [2,144,520ms] [Warning] [omni.physx.plugin] The rigid body at /World/turtlebot3_waffle/camera_rgb_frame has a possibly invalid inertia tensor of {1.0, 1.0, 1.0} and a negative mass, small sphere approximated inertia was used. Either specify correct values in the mass properties, or add collider(s) to any shape(s) that you wish to automatically compute mass properties for. If you do not want the objects to collide, add colliders regardless then disable the ‘enable collision’ property.
2023-06-05 16:28:43 [2,144,520ms] [Warning] [omni.physx.plugin] The rigid body at /World/turtlebot3_waffle/camera_rgb_optical_frame has a possibly invalid inertia tensor of {1.0, 1.0, 1.0} and a negative mass, small sphere approximated inertia was used. Either specify correct values in the mass properties, or add collider(s) to any shape(s) that you wish to automatically compute mass properties for. If you do not want the objects to collide, add colliders regardless then disable the ‘enable collision’ property.
2023-06-05 16:28:43 [2,144,520ms] [Warning] [omni.physx.plugin] The rigid body at /World/turtlebot3_waffle/imu_link has a possibly invalid inertia tensor of {1.0, 1.0, 1.0} and a negative mass, small sphere approximated inertia was used. Either specify correct values in the mass properties, or add collider(s) to any shape(s) that you wish to automatically compute mass properties for. If you do not want the objects to collide, add colliders regardless then disable the ‘enable collision’ property.

What does it mean?
Here is my asset layers.

image

Hi,
This means that there are no mass properties defined for those rigid bodies.

The mass properties are either defined from the collision shapes - using volume to compute the mass properties. If there are no colliders (which is most likely the case here) then there should be mass defined directly or as the warning says an approximation is used.

I am not that much familiar with the URDF importer, but it looks like either there are no collisions or mass properties are missing on these bodies.

Regards,
Ales