RC: create a 3d stl file for a rounded corner tray. 75mm wide x 180mm long x 15mm high. corners are 25mm radius. side walls to be 2.5mm thick.  tray walls top edge rounded on both inner & outer edges. bottom is 2mm thick.

Gem:

Did you have to install openSCAD and paste the Gemeni code into it?

Yeah, that was all.  Exported the stl and it loaded in Tinkercad without any flags or problems.

Thanks. I created a model today with Gem and ported to openSCAD. Sent it out to a bunch of laser cutters for quotes. The instant quotes were mind-blowingly high. 39" by 23.5" aluminum sheet to be laser cut with a .375" hexagon pattern... $1,500 is the best so far. Yikes.

application?
thickness?

I'm thinking CAD-driven cnc shops ought to be available around your locale.  A water-jet would likely work, though I don't know if they're even more expensive.

Well that's awesome. I usually spend most of my time making small enclosures when designing.