Some CAD/3D programs can process the vector drawings created using Adobe Illustrator and convert them to one of the CAD data formats. This is usually used in the case of logos and other geometric shapes. So it should be quite possible to convert AI to STEP.
Convert Adobe Illustrator graphics file to ISO-10303 STEP product data.
We found 3 software records in the database related to .ai to .step file format conversion.
Microsoft Windows software - convert ai to step on Windows
A 3D modelling software
Convert from ai file format
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned ai to step. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
A widely-used 3D animation application from Autodesk
A 2D, 3D modeling tool