Considering grains when calculating the mechanical response of a metallic alloy during L-PBF offers several advantages and perspectives, particularly in predicting anisotropic behaviour and intergranular fracture. At the scale of the melt pool and track formed, the epitaxial grain growth can be captured by a CAFE (cellular automata/finite elements) formulation and implemented in existing thermofluid numerical simulations. Subsequently, considering the grain structure in mechanical resolution is achieved using crystal plasticity, or rather crystal viscoplasticity, as calculations must be carried out over a wide temperature range. The presentation will discuss the different features of this approach and will include results in L-PBF of 316L stainless steel. At the scale of the component, the grain structure can no longer be calculated synchronously with the heat transfer and mechanics solution processes. This is because accurately simulating the transient melting and solidification throughout the entire L-PBF processing of a component is computationally unfeasible. The proposed strategy, therefore, consists in pre-calculating the grain structure at the part scale, using an original hybrid cellular automaton methodology [1,2]. This methodology generates the grain structure while incorporating the detailed scan path, assuming a steady state of the local thermal distribution and melt pool shape. Once completed, for each new layer built, the grain structure is made available for the crystal viscoplasticity model, in the framework of a layer-by-layer thermomechanical resolution. Since the fineness of the grain structure cannot be necessarily captured by the finite element mesh, a homogenization procedure is implemented to consider several grains within each finite element. Stress and distortion predictions will be presented for a small turbine propeller made of IN718. References [1] T. Camus, D. Maisonnette, O. Baulin, O. Senninger, G. Guillemot, C.-A. Gandin, Three-dimensional modeling of solidification grain structures generated by laser powder bed fusion, Materialia 30 (2023) 101804 [2] Y. Zhang, G. Guillemot, T. Camus, O. Senninger, M. Bellet, C.-A. Gandin, Part-scale thermomechanical and grain structure modeling for additive manufacturing: status and perspectives, Metals 14 (2024) 1173