Interior rendering makes use of special rendering algorithms that simulate and imitate the light transmission as it works in the real world. As regards the scene complexity, the interior creation is generally easier than exterior visualizations. There are no problems with the complex surroundings and extensive flora, which is beneficial for the possibility of modeling the individual objects in bigger detail and thus enhancing the visual quality. Interiors are, as opposed to exterior visualization, more demanding on the illumination quality. Proper interior illumination is half of the success and improves quality and observer’s satisfaction.

A number of techniques are used for interior illumination. The most frequent ones are radiosity, illumination via photon reflections, GI (global illumination). The simulation of light diffusion on edges is also widely used.

Interior rendering often makes use of more advanced materials and special settings for the glossy reflectivity of materials (so called glossy reflections) that simulate relief unevenness, creating visually immaculate materials, which intensify the scene’s final impression. Nowadays, it is recommended to get inspired by the reality as much as possible, which means to use reflectivity of all applied materials, because that is what reality is like. One must not forget to check the intensity and reflection gloss on the specific surface. So called Fresnel reflections are also common and simulate the effect of the real world when the reflectivity rate varies depending on the angle of view on the object. This effect is best manifested on the example of translucent glass. When we are looking at it vertically, we can see through, but as soon as we look from the side, the visual reflectivity increases.