.amf
AMF modelAdditive Manufacturing File Format
An XML format for 3D printing, published by ASTM in 2011 and later adopted by ISO. It adds curved triangles, colours, materials and lattices to the plain mesh idea of STL.
Multi-material and colour 3D prints in slicers that support it.
Opens in PrusaSlicer, Slic3r
About AMF files.usdz
USDZ model
A single-file, uncompressed ZIP package of Pixar’s Universal Scene Description, introduced by Apple and Pixar in 2018. It bundles a scene with its textures for AR on iPhone and iPad.
Augmented reality on Apple devices and 3D product views on websites.
Opens in Quick Look on iPhone, iPad and Mac, Reality Composer, Blender
About USDZ files