Three dimensional modeling of utility networks is an important mean of networks design, implementation, management and maintenance. During the modeling process, we face a wide range of processes and procedures to arrive at the correct final model. This research proposes a semi-automatic methodology for 3D modeling of infrastructure networks in GIS environment. This methodology is based on the ModelBuilder in ArcGIS software by developing two tools to automate the construction processes of 3D networks. The first presents a tool to create a 3D Manhole layer from points, and the second is a tool to create a 3D pipe layer. For both tools, a work algorithm has been built, in addition to designing user interfaces elements. These tools are stored in a Toolbox called “3D Manhole & Pipe.tbx”. The proposed methodology is an easy and an effective way to build 3D network models, and the developed tools allow the implementation of a set of necessary processes needed to build 3D networks.