My latest 3d modeling project in 1:100 scale (15mm) is a Wespe SPG.
The STLs are available now at
https://www.wargaming3d.com/product/wespe/It can be printed with the gun horizontal, or elevated in an indirect firing position.
I've provided it as a kit of four components (fighting compartment and gun, hull, and two running gear modules) as well as a complete model that can be printed in one piece if you don't mind all the work of clearing out supports afterwards.