Welcome back to the article series “AR design challenges and best practices”. As a reminder, this article series showcases several best practices and UI solutions relating to Augmented reality design challenges.
In today’s article, we will tackle the issue on “6 ways to increase AR playtime”.
Key device considerations – it’s heavier than you think
Imagine yourself holding a camera lens during an entire day to view the outside world, your arm would probably feel pain or end up being numb. This effect is known as the “Gorilla Arm”.
In AR, the users need to hold the device and constantly point the screen toward the scene to view the content. The arms are never at rest, and this makes it uncomfortable and tiring in an extended use.
Types of devices
Depending on the type of device the user interacts with, it will drastically affect their time of use and increase the chances of drop out. For instance, a tablet weighs more than a smartphone and it is wider causing greater motion being required to reach the elements.
How users interact with 3D elements
Depending on the type of device being used, the location of the interaction controls, the user can either use one hand or two hands to hold the device and interact with the application.
As a designer, we must be careful on how we allow the user to interact with 3D elements and where we place the controls. Interactive controls can either be located on the 2D screen in a fixed position (commonly referred to as “Screen Space”) or in the 3D scene (referred to as the “World Space” ).
According to Apple, there are two main methods of interaction controls: direct controls or indirect controls.
A direct “control” or interaction refers to the direct manipulation of 3D elements. Typically, one could directly “tap” onto the 3D element located in the scene. This interaction is natural and therefore more intuitive, however, as a downside, it requires more finger motion.
Indirect interaction, on the other hand, involves the use of buttons that are not part of the virtual environment. Typically, we’ll use 2D buttons fixed onto the screen to interact with the 3D object targeted by the crosshairs aka the “reticle”. This interaction, although less “natural”, is more comfortable, since the action button remains more reachable for the thumb.
In a case where a user has to hold the device with both of his hands and in an interaction that favors direct interaction with the 3D elements, one hand would be used to hold the device and control the camera while his second hand will be used to interact directly with the 3D element (as shown in the image below).
This scenario, causes the most fatigue, as the user must constantly move his hand to interact with an element. This selection mode is also less precise in a case where the selectable 3D elements are small. Indeed, the user has to stabilize his tablet acting as a camera while trying to select an element from the 3D scene.
Standing vs Seated mode
The user’s posture, whether sitting or standing, also influences the time of use. Although the standing mode is very engaging and immersive since the user has to stand up to explore the 3D scenery, it can be very tiring having each time to physically move toward the objects you want to interact with.
So there’s a lot to consider
In all, depending on the type of device being used, the type of interaction controls that have been set up, combined with the amount of physical motion being required, each contributes to increase user fatigue that can damage the user experience. So, here are some interesting solutions brought by Designers on how to increase the AR playtime that might help solve or circumvent that issue.
1 – Pace it
Alternate the use of Augmented Reality.
Content that does not require any interaction can be made accessible in a Non-AR passive viewing mode. For instance, reading a heavy text content can be viewed in a standard 2D “screen space” since it does not require any AR.
Although less immersive, the display in “screen space” allows the user to rest his arms for a certain time.
2 – Bring it closer
We can also consider alternating between the standing mode and seated mode. By bringing the 3D scene closer to the viewer or providing a reset position button, so that the user won’t have to physically move to adjust his viewpoint.
Another good practice is to allow the user to edit the object or scene rotation independently from his position. This again avoids having to physically move around the object to adjust the viewpoint.
3 – Make it reachable from far away
We can also increase the size of the “touch targets” of the object so that the user can access it comfortably at any distance.
Google suggests increasing the size of the touch target dynamically based on the distance from the user, to ensure the user can trigger it.
You’ll notice that the touch target represented by a dotted line of the left tennis ball will be harder to trigger as opposed to the right one. This dynamical sizing prevents the user from having to physically move toward a 3D object to interact with it.
4 – Make the 3D scene accessible in a Non-AR mode
To increase the time of use we can also carefully limiting the use of augmented reality.
We can provide alternate ways to access the 3D content if no AR is needed. Say by making the 3D world viewable in a Non-AR mode.
In “iStaging” there is a 3D preview mode of a model. This empowers the user with the choice of either using AR mode to get a sense of scale in his context or to use the isolated 3D view mode to study the 3D shape and texture of the model at his own pace.
5 – Time it
In “A&E® Crime Scene AR” (an AR crime scene investigation game), the player’s score is based on the time he spends solving the case. The user has to pause the game and thus the timer, so that he doesn’t waste precious time on thinking.
This gameplay ensures occasional Augmented Reality breaks.
Time is an interesting asset, one could also have imagined limiting the time of use, by either adding mandatory breaks (such as advertising content) or by using a countdown, as this would force the user to take breaks while making the experience more challenging.
6 – Plan your interaction controls
We can provide appropriate interaction means to limit user fatigue.
If fatigue is a major concern and we are expecting users to interact in AR for a long period of time, then we might consider using indirect controls as means of interaction. In “Conduct AR” (a mobile train simulation game in AR), they have used the center of the screen acting as a pointer (commonly referred to as “Reticle”) that highlights 3D elements form the scene and displays the contextual buttons onto the sides of the screen near the thumb position.
This interaction, makes it easier and more accessible to interact with virtual objects in the scene, since the thumbs remain at the same position. The users only has to aim and tap with the thumbs.
This indirect interaction:
– improves the access of the interaction controls
– reduces fatigue since the thumbs remain in the same position
– reduces selection errors
Although less “natural” than a direct object selection, this interaction mechanism offers more comfort for a long-lasting use.
AR requires the user to frame his 3D environment to view his content.
This multitasking between controlling the camera and interacting with the scene is more tedious than Non-AR apps and can yield fatigue in an extended use. So we can either plan for a shorter use of AR or try out some other alternatives.
In all, to increase AR playtime we can :
- Alternate the rhythm or AR use
- Bring the 3D scene closer to the user.
- Maintain the element “touchable” at a far distance.
- Provide a Non-AR 3D model preview or by making the scenery persistent.
- Limit the time of use by adding breaks or a countdown.
- Use indirect interactions to increase comfort and reduce fatigue.
So how about you, did you come up with other solutions?
Sources applications :
A&E® Crime Scene: AR
Mercedes-Benz FACTORY 4.0
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