For hobbyists (and why not Pros) a free cool one can be the Free Real Time Sim Lab Composer Lite ! (Maxi 1920 *1080)
http://www.simlab-soft.com/3d-products/simlab-composer-lite.aspx
Very easy use "keyshot like" ;)

It can accept quasi all 3D formats! So you can make directly any assembly from Cad formats + obj formats!! ;)
But even it has .3dm, that will not work with MOI!!! (don't know if it's the same for Rhino but I suppose! )
(surely Nurbs / Polygons problems ) Michael will be more advised than me of that! ;)

Prefere Quad + triangles or Triangles even it accepts Ngones for The OBJ format from Moi!
Make your own try! :)

Have fun rendering!

With a Moi Object! ;)






Just take a texture with alpha holes! ;)





With a ZBrush Model!


With SketchUp Objects
Free http://www.3darcstudio.com/fr/telechargements/26-3d-tree-maker-sketchup-plugin.html
for free version Make! (now only old 2017 Make as last free version of SketchUp is only online and don't support plugings!)
https://www.sketchup.com/fr/download/all#fr




By Matt-one with a model made with the free Lego Designer! :)
http://ldd.lego.com



Always amazed how hundred of things are calculated in Real Time!