In September 2026, Springer's The International Journal of Advanced Manufacturing Technology published the paper "In situ real-time 4D imaging of surface evolution in laser powder bed fusion," which integrates fringe projection profilometry (FPP) into a commercial LPBF system to enable continuous, time-resolved, in situ 4D (x, y, z, time) surface topography monitoring throughout the entire printing process — including powder spreading, contour scanning, infill scanning, and layer completion. Methodologically, three-step phase shifting combined with dual-frequency phase unwrapping (the Hyun & Zhang method) is used to reconstruct the 3D surface topography at each time point, with continuous acquisition spanning all stages from powder spreading to layer finishing; reconstructed surfaces from adjacent layers are registered into a unified coordinate system, enabling visualization of layer-by-layer material accumulation and extraction of surface roughness parameters (Sa, Sq, Ssk, Sku) within the laser-affected zone to quantify local geometric changes. For powder buyers, the value is twofold: (1) This 4D in situ monitoring directly links powder spreading uniformity, spatter, and defects to powder flowability, sphericity, and particle size distribution, allowing the impact of powder batch quality on build stability to be quantified layer-by-layer for the first time; (2) Powder manufacturers capable of "feeding monitoring data back into powder grade certification" can establish differentiated quality inspection and quality assurance credentials.