Designed this as a "moto mod" car vent mount for my Moto Z. Should work in Moto Z Play too, since the moto mods are in the same shape.
I used 20x10x2 mm magnets that i bought from Aliexpress some time ago. They are really strong, but since they are some millimiters away from the phone (because of the printing layers), they do not attach ultra-strong agains the phone. If you are going to use weak magnets, make them closer to the phone (but watch out if they dont rip the layers off when you force to separate).
There is a feature that is really missing! In the center of the gold connectors there is a central pin that is used for centralizing the moto mod. I could not add this without adding huge supports. A two-pice shell would be perfect...... One just with the centralizing pin...
Dimensional are quite good. There are 2mm missing in the bottom. If you are obssesed with perfection, fell free to work on it...