stl to force a custom bottom pattern in cura. add this to any cura scene you are slicing,

enable these settings in cura: Bottom Pattern Initial Layer = Concentric Merged Meshes Overlap = 0.01mm Remove Mesh Intersection = True Alternate Mesh Intersection = True

the main file is just a repeated zig zag that is 0.1mmx0.1mm cross section.

The bigger one labeled .2x.4 was a bigger cross section i made before figuring out the right settings.