How to Plan a Building Projection, Step by Step

A building projection looks effortless on the night, but it is the result of weeks or months of planning. This checklist follows the workflow used by mapping studios for festival and event facades. Adapt the scale to your project.

1. Define the brief

Write down the essentials before anything else: the building, the date(s) and duration, the expected audience size and where they will stand, the story or message, whether sound is needed, and the budget. These decide almost every technical choice. A 3-minute loop for a festival is a very different project from a 20-minute narrative show with a live orchestra.

2. Survey the site — at night

Visit the site after dark, ideally at the time of the show. Record:

Ambient light: streetlights, illuminated shop signs, the building's own facade lighting. Measure with a lux meter or phone app; anything above 10–20 lux on the facade will noticeably wash out projection. Ask early whether lights can be switched off.
Viewing areas: where the crowd will stand, sightlines, safety exits. 3D illusions work best from one main viewpoint.
Projector positions: a building opposite, a rooftop, a scaffold projection tower in the square. Measure distances and angles to the facade.
Power and cable routes, access for vehicles and cranes, and any trees, flags or tram wires in the beam.
Surface: colour and reflectance (light stone is easy, dark brick or glass is hard), recesses, balconies, windows.

3. Get permissions early

You will typically need consent from the building owner, the city (public space, traffic and event permits), sometimes heritage authorities, and the owner of the building where projectors stand. Large events need a safety plan, crowd management, insurance and possibly noise permits. Lasers have separate rules in many countries.

4. Choose projectors and lenses

Work out the projected area (width × height of the facade you will actually cover) and the distance from the projector position.

Lens: divide distance by image width to get the required throw ratio, then pick a lens whose zoom range includes it. Our throw-distance calculator does this for you, and every model page in the projector database lists optional lenses.
Brightness: estimate the lumens needed from area, ambient light and target contrast with the brightness calculator. Outdoors, plan for at least 5:1 contrast against ambient light, and ideally 10:1 or more.
Layout: split wide facades across several projectors with 10–20% edge-blend overlaps, or stack projectors to double brightness. Check resolution with the edge-blending calculator.
Resilience: use laser projectors that can be tilted, keep spares, and protect everything in weatherproof housings.

5. Build the template or 3D model

Content must match the building exactly. Options, from quick to precise:

Photograph the facade from the projector position and trace it into a mapping template.
Build a 3D model from architectural drawings.
Use drone photogrammetry or a laser scan for complex heritage buildings.

Export a template image at the final canvas resolution so designers can animate on top of it.

6. Produce the content

Write a storyboard around the building's history and architecture — the best festival works feel as if they could only exist on that facade. Plan the soundtrack together with the visuals. Render tests early and project them on site (even with a small projector) to check scale, contrast and readability: thin lines and dark colours disappear outdoors, while bold shapes and high contrast read well from far away. Keep text to a minimum.

7. Technical rehearsal

Arrive several nights before the show. Rig projectors, align them, warp and blend, then mask the sky, roofs and neighbouring buildings. Check colour matching between projectors and brightness uniformity in blend zones. Run the full show at least twice with sound, and test failover — what happens if a projector or computer stops?

8. Show nights

Keep a crew on site, check weather forecasts (wind limits for towers, rain, fog) and log any issues. After the event, document the work with good video from the main viewpoint — it is your portfolio and your entry to the next festival open call.

FAQ

How long does it take to produce a facade projection?

A simple 2D festival loop can be produced in two to four weeks; a narrative 3D show with original music often takes two to four months including permissions.

How far away can the projectors be?

As far as the lens allows: long-throw lenses with ratios above 4:1 can project across a wide square. The limit is usually brightness — longer lenses can cost light — and obstacles in the beam.

What if the building is dark or has lots of glass?

Dark surfaces need far more light, and glass reflects or transmits it. Concentrate content on the light, solid areas, mask the windows, or add temporary covering to windows where allowed.