Maybe these links will help you:
https://www.bigredboots.com/westwood/...SolidText.html
https://www.drone.org/tutorials/light...t_objects.html
https://www.highend3d.com/maya/tutorials/bakeshadows/
The second one lists a few scripts you can use if you're using raytracing since the first method only works with depth map shadows (not sure if this has been implemented in current versions of maya & MR, though...someone can chime in if they know for certain).
"Terminat Bora Diem, Terminal Auctor opus."