Orange Pi Zero 3 top case with top grill for expansion board and the aluminum heatsink case

I liked the design for the original model but didn't like that it required using brass inserts for the screw. I didn't have those in my box of misc stuff for projects and didn't want to have to buy a box of them just to use the number required for this case. I also wanted better cooling with the case top facing up. I also had no need for the bracket holes as I didn't plan on mounting this on any of my printers. 

So, I removed the side holes for mounting the case onto a bracket, I added small hexagon shaped vent holes to the top of the mode to better help with cooling with the top facing up. I slightly enlarged the sd card slot as I ran into problems with the first version of the remix for the sd card getting stuck inside the slot for the case when inserted. I also reworked the screws so a M3 screw is able to screw down into the posts without having to use brass inserts because I didn't have those to use, and wasn't keen on buying a whole box of them just for this case. 

I printed this with the top facing the print bed, and I used 0.2mm height for the print with organic tree supports with the painted supports option in Orca Slicer to prevent tree supports for being used for the small vent holes.

You may also be able to just use standard supports then use a exacto knife to carefully cut out the various holes if they don't easily pop out for you.