It seems the only way to produce .tdi file from Adobe Illustrator graphics (.ai), would be to first open your .ai file using Adobe Photoshop and export the file from it as bitmap. May require some plugin of sorts for the TDI format. This will be basically a vector to bitmap conversion, so the result may not be poor compared to the original.
Convert Adobe Illustrator graphics file to Explore (TDI) & Maya image file (IFF format).
We found one software available in the database for this conversion.
Microsoft Windows software - convert ai to tdi on Windows
One of the best bitmap graphic editing program
Convert from ai file format
The table with program actions contains information about what each program is capable of doing with their files. This may be a good pointer for further searches for certain file conversions and help you find the converter you are looking for if our search result is insufficient for you. However, it is far from perfect and may sometimes show results which are not really usable because of the nature of the software handles the files. So a conversion that appears as possible, just because of matched actions, may in fact not be possible.