Exploration IRIS Kanaleneiland

Digital impacting physical

This post is part of a series we wrote after wrapping up the IRIS project.

Design notes part 1: Digital impacting Physical

When building a mixed-reality setup, the digital components impose some limits on the physical aspects. Ideally, you would like to move all components to the realm (digital/physical) in which they are the easiest and/or most effective to implement, but due to the restrictions of technologies this is not always possible. Here are some examples of how the technologies we used impacted our design choices.

Pepper’s Ghost screens

The technology has to work effectively in the box you design. As the Pepper’s Ghost effect works with a 45-degree-angled screen, this screen needs to fit the apartment and its furniture. Furthermore, the effect works best when viewed from the front. Although it has a reasonable viewing angle, it will not work at all when viewed from the sides as you will look onto the edge of the screen. This way, the box needs to be built ‘peep box style’, with only visibility from the direct front.

Most practical, the size of the box is determined by the size of the screen you use for projecting the Pepper’s Ghost. In our case we went for a 15,6“ screen, which meant the effective width of the play area inside the box could be no wider than 34,4 cm.


During development we found that lighting can be done both through the digital layer and the physical layer. Atmospheric lighting can be generated by the laptop screen, but also by LEDs in the box. However, too many lights within the box will wash out the visibility of the digital layer.

The box also needs to prevent too much ambient light to flood in from outside the box, as this will reduce visibility as well. In order to do so, we designed the physical box so it is fully enclosed form all sides except the front from where the players look inside. All the lights inside the box are precisely dimmed so that even when they simulate daylight conditions, they are bright enough to light the scene, yet they are dim enough not the wash out the peppers ghost effect. This part took some trial and error to figure out.

Even with these precautions, the effect works best when you avoid any light from coming into the box from behind the player. Therefore the front of the box should not face windows or lamps as this could result in reflections on the screen, spoiling the effect.

Part 1: Mixed Realities during Lockdown Measures

Part 3: Design 2: physical impacting digital

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