Architectural photomontage is a frequently used technique, especially for exterior architectural visualizations, as it enables us to achieve results faster in comparison to creating the entire scene in 3D and at the same time, maintains the high quality of the output.

Its procedure involves taking a photo of a place where the processed object is supposed to be. The photo quality is essential and has a big role, that is why it pays off to pay enough attention to it, select the right angle for the shot, wait for the right illumination etc. Very often, the entire surroundings are also photographed for the real reflections on the object.

Next, the perspective of the modeled object, prepared in the 3D program, is adjusted to the photo perspective – this act is termed "Camera match". In detail, it means selecting the characteristic points that define the photo and 3D model perspective and assembling them using the descriptive geometry methods.

An illumination and reflection setting is a stage of no lesser importance. The common method is using so called HDRI map that keeps the light conditions and is therefore suitable as the map of surroundings for displaying the reflections on the object. This map is applied to the area around an object and is used to create a quality imitation of the environment captured in the HDRI map – photo.

Once the rendering - calculation of a final 3D image of an object is done, the image is merged with the original photo in the composing program. That is how the perfect illusion of reality is built. As the rendered object takes up only a part of the photo, it is often very difficult to tell the architectural photomontage from the actual photo of some architecture.