Auto-trace creates Surface Draw and needs the project to have at least one Surface (see also Surface Drawing). All the Surface Draw is assigned to the first Surface in the project. If you are using the Template Pattern Capture project wizard to set up and solve your projects then a Plane Surface has already been created for you. For the tracings (Surface Draw data) to be exported, this Surface must be solved in 3D.
In addition, Auto-trace typically needs the photograph, where tracing is being done, to be solved and oriented. If it is not oriented, Auto-trace will function but with warning messages about missing scale. Without a solution to the camera and the surface, an assumption is made that a photo pixel is 1mm – this might affect how the parameters (such as tolerance, etc.) function.
See also Advanced Auto-trace Debugging if you’re having trouble with the process.