Among the advanced powder processing techniques, the two of the most promising are field-assisted powder consolidation (e.g., spark-plasma sintering) and additive powder-based manufacturing (3-D printing with selective laser sintering, binder jetting with follow-up sintering, and fused deposition of metal and ceramic powders). However, physical mechanisms underlying the specifics of these modern material processing approaches, taking into account new  driving  forces,  and  new  mechanisms  and interplay of processes at different structural levels, are unclear. The specifics of powder material structures produced by additive manufacturing (such as binder-jetting, stereolithography, robocasting, selective laser sintering, etc.) of complex-shape powder-components necessitate fine-tuning (optimization) of sintering as applied to porous 3D-printing products. In its turn, the optimization of the additive manufacturing of green parts improves the quality of the final parts produced (shape distortions, surface roughness, residual porosity) as well as the consecutive sintering steps. The sintering stage entails in-depth understanding of high- temperature deformation behavior of the 3-D printed porous specimens. In particular, the effects of fabrication directionality and gravity on micro- and macro-structure of sintered components are still poorly understood. The densification of complex shapes requires control of the gravity-related and anisotropy phenomena to ensure a nearly full and distortion-free densification. Thus, the 3-D printed microstructures have unique features that require the development/modification of sintering theories. The conducted studies address these issues through the involvement of modified sintering constitutive models, comprehensive finite element simulations, and the experimental validation of the developed models describing sintering of 3D-printed objects as compared to sintering of conventionally produced porous sintering preforms. The validation of the developed models is conducted through the comparison with the experimental results obtained for the sintering of the printed powder components.