Laser powder bed fusion (L-PBF) is an additive manufacturing process in which a laser melts powdered material layer by layer and forms a component by re-solidification. The local application of the laser leads to high heating and cooling rates as well as huge temperature gradients and can lead, in worst case, to material decreasing effects such as pores and cracks. The entire process spans different time and length scales, with effects from each scale interchanging. Numerical simulation tools are needed to understand the complex parameter interactions and to exploit the full potential of this manufacturing process. This presentation deals with the modeling of material parameters for the macroscale using Discrete Element Methods (DEM) and Computational Fluid Dynamics (CFD) on the one hand, and how to build part-scale simulations based on Graphical Processing Units (GPU) and Finite Difference Methods (FDM) on the other hand and shows first minor results of our work in the field of additive manufacturing simulation. By combining different simulation approaches for different scales, a holistic modeling approach is achieved that is able to capture essential effects from the different scales and lead to efficient simulations.