Visualization in architecture is crucial, because it is an essential way of communication between architects and clients or users. Normally, images or video renders are used, which can take hours to generate a visualization and all the end user can do is to watch it. Ever more powerful computer systems, whether desktop or mobile, and the availability of free very advanced and powerful game engines offer us possibilities to create real-time, realistic and interactive applications. The aim of this thesis is to create an application for interactive visualization of architecture, concept of a new cultural center in Maribor, using the Unity3D game engine. The user can manipulate the outside and inside lighting conditions, so it can observe how light interacts with the architecture. We also depict very basic agents (people and vehicles) that are walking in and around the building or are driving on the roads in the immediate vicinity. In order to be accessible to the widest range of users, we wanted to support many platforms, but due to the amount of extra work and hardware limitations of mobile devices we limited ourselves to desktop systems (OSX, Microsoft Windows, Linux).