You can find several CAD / 3D modeling translation tools that will allow you to convert .iv files (SGI Inventor 3D format) to standard ISO STEP format (.stp, .step). This conversion is probably used by users that try to convert their old .iv format to some exchange format supported in modern programs.
Convert SGI Inventor 3D format to ISO-10303 STEP product data.
We found 2 software records in the database related to .iv to .step file format conversion.
Microsoft Windows software - convert iv to step on Windows
3D viewer and converter with huge file type support
Convert from iv 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 iv 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 CAD viewer program with conversion capabilities