KiSSAM Simulation Software for Additive Manufacturing (KiSSAM) is a multiphysics simulation software designed primarily for high-performance and high-fidelity three-dimensional simulation of metal laser and electron beam powder bed fusion (PBF) additive manufacturing processes at the melt pool level. The core of KiSSAM is a high-performance fluid dynamic and heat transfer solver based on the lattice Boltzmann method. KiSSAM physical model includes all physical effects which are known to be necessary for the high-fidelity simulation, including the unsteady melt flow, free surface and wetting effects, Marangoni convection, recoil pressure, multicomponent evaporation, heat conduction, laser multiple reflections, electrons scattering, flow in the mushy zone and others. Details of the physical models implementation in KiSSAM are described in [1]. Multiscale simulation data is effectively stored using a special hierarchy of adaptive grids. Melt pool domain is always highly resolved during the simulation with a typical space resolution of 3-5 μm. Temperature data is stored on an adaptive rectilinear “tractile” mesh on the scale up to a whole 3D printing chamber (about 100 cm^3). The geometry of the powder and melted material is adaptively tracked with the help of the openVDB library [2] and the resulting geometry grids are stored in VDB format with chamber dimensions and resolution of 3-5 μm. The software utilizes the modern Graphical Processing Units (GPU) resulting in incredible simulation performance. Simulation time is approximately 1-2 hours per single track, 10-20 hours per single layer, 100--200 hours per volume simulation on a single GPU. For high-fidelity simulations with the powder, KiSSAM is equipped with a powder generation module based on fast and accurate GPU discrete element method implementation adapted to simulate the powder feeding process in the PBF. User cases of KiSSAM usage for the PBF processes simulation include but are not limited to the bead on plate and bead on powder process map building, porosity estimation, overhang, thin-walled and fine structures simulation, temperature history prediction, change in the percentage of the alloy components calculation, simulation of downbeam camera and photodiode sensors response, wobbling and multibeam strategies simulation. Web interface for KiSSAM is being developed www.kissam.cloud for more details).