Users who only have AutoCAD but want to see ProSteel/ProStructures objects in AutoCAD you can do this by having an Object Enabler installed in your machine.
You would need to choose the Object enabler that is the same version that the file was originally created.
Contact the source if you are unsure what version the file was created.
ProStructures V8i / CONNECT Object Enabler / Plug In for AutoCAD and Other applications
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