  In the past few years, the widespread use of 3D printing technology enables
the growth of the market of 3D printed products. On Esty, a website focused on
handmade items, hundreds of individual entrepreneurs are selling their 3D
printed products. Inspired by the positive effects of machine-readable tags,
like barcodes, on daily product marketing, we propose AnisoTag, a novel tagging
method to encode data on the 2D surface of 3D printed objects based on
reflection anisotropy. AnisoTag has an unobtrusive appearance and much lower
extraction computational complexity, contributing to a lightweight low-cost
tagging system for individual entrepreneurs. On AnisoTag, data are encoded by
the proposed tool as reflective anisotropic microstructures, which would
reflect distinct illumination patterns when irradiating by collimated laser.
Based on it, we implement a real-time detection prototype with inexpensive
hardware to determine the reflected illumination pattern and decode data
according to their mapping. We evaluate AnisoTag with various 3D printer
brands, filaments, and printing parameters, demonstrating its superior
usability, accessibility, and reliability for practical usage.
