DIALux is a functional program for interior and street lighting design. The application allows you to interactively plan the location of luminaires, color filters, painted materials and view the resulting scenes in the form of photorealistic 3D-models. The program can create the whole film simulating a walk through the designed room. In the construction of three-dimensional interiors DIALux uses realistic textures and modern technology of scene lighting. Despite the wealth of opportunities, working with the program does not cause difficulties and is based on step-by-step instructions. Supports integration with 3DS objects, exporting and importing files into DWG and DXF formats. A reference is available.