No More flat Sliders: Designing Interfaces in a 3D Reality

The leading platform for creating virtual reality (VR) interactions today is Unity, widely adopted for developing immersive experiences ranging from infotainment applications to games. While traditional user interface (UI) design principles for 2D mobile apps and websites provide a foundational reference, designing UI for VR demands an entirely distinct approach. This necessity arises from unique spatial considerations and limitations inherent to immersive environments — such as restricted fields of vision, depth perception challenges, ergonomic comfort, accessibility factors, and interaction precision. In this article, we will explore these specialized design principles and propose insights on developing a more effective and user-friendly VR UI library.

According to the article Toggle-Switch Guidelines from Nielsen Norman Group, toggle switches are digital on/off switches. They prompt users to choose between two mutually exclusive options and always have a default value. Toggles should provide immediate results, giving users the freedom to control their preferences as needed. However, in spatial environments, typical 2D UI elements like flat toggles become challenging to implement effectively. Traditionally, a toggle requires sliding interaction — moving it to the right to activate — but executing precise sliding motions in VR, whether through hand-tracking or controllers, can be cumbersome and unintuitive. Therefore, it becomes essential to rethink and redesign interactions to suit spatial contexts more naturally.

Among various design explorations in this space, Oleg Frolov, an experienced design engineer, has contributed significantly by developing interface properties specifically aimed at increasing spatial awareness of UI elements. His work focuses on enhancing precision in body movements and aiming interactions within virtual environments. As he mentioned in the post from LinkedIn:

“A few people asked me if there are benefits of using 3D over 2D UI. I believe that using 3D interfaces for spatial interactions that involve the human body allows you to utilize additional visual cues, such as shadows, highlights, and reflections.”

Here’s an example that he added pressing states, toggle group processing, sounds, and pointer/direct touch to the 3D toggle element.

In addition to these spatial awareness enhancements, Frolov also reimagined traditional UI components by introducing visually engaging design elements. For example, he redesigned the buttons with a distinctive RGB offset effect, adding both aesthetic appeal and functional clarity to interactions in immersive virtual spaces.

As VR interaction designers, we must prioritize accessibility, considering diverse user groups such as left-handed individuals, elderly users, young children, individuals with mobility impairments, and those with varying cognitive or sensory capabilities.

Our goal is to develop interactions that feel natural and intuitive, effectively normalizing the feedback loop between hand muscles and the brain when engaging with virtual elements. This involves thoughtfully determining interaction methods — such as poking, pinching, grabbing, gesturing, or leveraging gaze-based input — to ensure inclusivity, comfort, and ease of use for all users.

Further exploration and research into innovative VR interaction techniques are essential. Comparative prototyping, rigorous usability testing, and user-centered evaluations will provide actionable insights, driving the refinement of interactions that genuinely align with user needs and capabilities in VR.