Architected materials and structures have gained increasing attention for their unique properties and broad industrial applications. Additive manufacturing now enables the precise fabrication of well-controlled architectures, such as periodic or quasiperiodic lattice structures, allowing, among others, for lightweight, stiff, stretchable, or multifunctional components. However, their complexity poses challenges for numerical simulation. While homogenization-based methods are common, they may face limitations, particularly due to insufficient scale separation in practice. As a result, dedicated efficient strategies based on fine-scale modeling and simulation, i.e., involving the full discretization of the architectural geometry, are emerging. This mini-symposium aims to gather contributions focused on the modeling, simulation, and optimization of architected materials and structures using advanced fine-scale-based methods. Topics of interest include, but are not limited to: (1) leveraging advanced computational techniques—such as isogeometric analysis, beam and shell models, immersed methods, or (machine learning-based) surrogate modeling approaches—for accurate and efficient simulations; (2) analyzing nonlinear or inelastic responses and stability; (3) developing digital twins that account for process-induced properties and defects; and (4) integrating simulations and experiments to validate models and better understand the underlying mechanical behavior.