Which tool defines a motion between components using their current positions?

The As-Built Joint is the correct choice because it is specifically designed to define motion between components based on their existing positions in a mechanical assembly. When utilizing the As-Built Joint tool, you can establish relationships between components that are already in place, allowing for flexible movement or constraints that account for their current orientation and placement. This is particularly useful in scenarios where components may not be perfectly aligned or may have been assembled in a non-standard way, as it relies on their actual positions rather than requiring predefined setup or constraints.

In contrast, the Motion Manager focuses on animating and simulating movement but does not directly account for the assembly's existing conditions. The Dynamic Link is often associated with linking data between software or features rather than defining physical motion in an assembly. A Fixed Joint simply locks components in place, preventing any movement, which does not meet the criteria of defining motion.