For anyone who still wants/needs to do this, and has Adobe CC anyway, there is a quick and relatively painless route now it seems.
I just exported an obj with diffuse colour materials, and it retained these. New 3D Layer from File in Photoshop, then right click Export 3D Layer. You don’t need Acrobat Pro/writer as far as I’m aware.
I’ll update with basic objects later pehaps.
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