Concrete is globally the most used building material. This fact shows the need to make advances in the prediction of its mechanical behavior. Despite being considered homogenous in many cases for simplification purposes, this material naturally has a high degree of heterogeneity, which presents challenges in terms of fracture process modeling, due to phenomena such as scale effect and softening behavior. In this context, the objective of this work is to present a 3D probabilistic cracking model based on the finite element method, in which material discontinuities are explicitly represented by interface elements. The threedimensional modeling of cracks makes it possible to analyze the fracture process in a more realistic way. In order to estimate statistical parameters that define the material heterogeneity, an inverse analysis procedure was performed using general laws defined by experimental investigations. The model and the inverse analysis strategy were validated mainly by the verification of scale effect at a level similar to that experimentally observed, taking into account the tensile failure of plain concretes. Results also indicate that different softening levels can be obtained.