When choosing an adequate position for the construction of a new transmission line, various parameters must be taken into account that affect the functionality of the transmission line itself, but also the assessment of the risk of the transmission line interfering with the surrounding vegetation. Technical problems in the construction of new transmission line routes can be solved with professional knowledge, but during the construction of the transmission line there is also the problem of environmental impact, the surrounding elements next to which the transmission line would be built, etc. In order to improve and facilitate the development of the transmission line, there was a need to create a program that will display the desired transmission line in a real dimension in the desired location, in other words - to display its 3D model. 3D-visualization significantly contributes to the understanding of the relationship between the overhead high-voltage line and the surrounding objects in space, and such a program was the goal of this thesis. In this thesis, various methods have been developed for generating a complete transmission line pole, either tension or load-bearing, different versions of the shape of the transmission line pole head (jela, dvostruka jela, dunav, bačva, mačka, Y) as well as lines and protection ropes. The methods are developed modularly so that it is easy to generate a new transmission line pole head shape for example, and are written in the Java programming language. Executing the methods produces models in the COLLADA format. The program also creates a KML file which contains all the data of the transmission line and the models that are displayed in it. Each model has its own latitude and longitude, rotation with respect to the z axis, altitude, and location where that model is actually located. The KML file can be opened in the Google Earth program and thus visually display all modeled parts of the transmission line.