Could be due to many reasons. General problem solving that I figured out after much trial and error:
Get the latest version of the exporter
Re-check the joint creation order (which component is the parent and which is the child... in README)
Check the names of the joints:
If the joint names are "Joint 1" change it to "joint_1" (remove spaces and make 1st letter lower case, replace spaces with
underscores)
Check the names of the links:
If the link names are "Link 1" change it to "link_1" (remove spaces and make 1st letter lower case, replace spaces with
underscores)
Create a milestone before using the exporter (revert model back to this if export failed)
For complex joints, kinematic loops, etc, follow this README file (It is a fork of trial and error and constant iterations that I have created for my own project)
Finally before URDF export, click on " DO NOT CAPTURE DESIGN HISTORY "
Close the issue if this solves the problem
I am new to ROS and fusion 360. Can anyone explain why I am having this error?