Determine the facade or angle of a building you will project onto. Corners of buildings and buildings with jut outs, surface detail or multiple openings are excellent, because the buildings already model the facades with three-dimensional surface variation. However, flat facades will work, as well.
Photograph the building from the precise angle and location you will project onto the building. Observe any three-dimensional volumes that extend from the building facades, such as balconies, bay windows and mechanical equipment, and record their locations and relative dimensions on a sheet of paper. These elements will be very important in creating three-dimensional projections on the building, because the images can project on these, and the extending volumes will cast shadows from the projection.
Scan or download your building photo into your computer. Open the image-editing software and create a new image file.
Import your building photo onto a layer in your editing software and create a new layer above the photo layer. Draw or import images on layers over the building photo layer. Skew and scale the images to align with the building facade and elements.
Create another layer and change the fill color to black. Draw an outline over the objects to project as three-dimensional and fill the selection outline with black. The black forms will become shadows in the projection. To produce the illusion of depth, move the black forms away from the objects to produce drop shadows on the building surface. Skew, scale and blur the forms to increase the illusion of depth in the projection. Move the layer below your three-dimensional projection image layer or cut and paste the shadows into the layer.
Fill the initial building image layer with black, so the image cannot be seen. Save the image as a JPG, TIF or PNG. Project the image onto the building face from the exact position you took the photo of the building. Use a projector with a high lumen rating, such as 10,000 or 15,000, to increase the quality and illusion of the projection. Lumens are a measurement of light and are directly related to the wattage of the projector's lamp. Adjust the projector settings to remove projection flaws, such as skewing, keystoning and blurring.