Thin films composed of single-walled carbon nanotubes (SWCNTs) have been proposed as a possible multifunctional material for aerospace applications, but before these materials can experience industrial acceptance the underlying mechanisms dictating their performance must be understood. Physics-based computational tools must be developed that allow studies in the final part performance, to aid in industrial acceptance. This works presents a full 3D computational modeling approach to study the electrical and thermal behavior of a neat CNT network. The model is based on physics based stochastic distributions for the SWCNT length, diameter, and chirality, SWCNT orientation in a network, and the separation distance between two adjacent overlapping tubes. Previous models did not allow for the physically relevant distributions for nanotube geometry to serve as inputs, and results presented in the present work indicate the sensitivity of the bulk network conductivity to small deviations in the stochastic inputs. The uniqueness of this model lies in its three dimensional nature as previous attempts to predict the behavior of SWCNT thin films assume the film to be a 2D network of CNTs and results show that this is insufficient to accurately predict the thermal and electrical conductive properties. The 3D model is validated against experimental results available in the literature, and comparisons are made between the 3D and 2D network models.