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Best practices for mobile UI design – part 1

January 31, 2023 in Games | 16 min. read
Best practices for mobile UI design – part 1 | Hero image
Best practices for mobile UI design – part 1 | Hero image

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Mobile UI design can be challenging, and with the number of games and devices growing at an exponential rate, crafting the most performant game has become a major priority.

We sat down with Outfit7’s Senior Software Engineer Aleksander Gregorka and UI Designer Maja Nadvešnik, Samsung’s Developer Relations Engineer Søren Klit Lambaek, as well as Unity’s Senior Product Designer (UI Tools) Stefania Valoroso and Senior Technical Product Manager Benoit Dupuis, for a two-part interview to get their practical advice and tips for effective mobile UI design.

In part one of the Q&A, they discuss the UI design process and device-specific challenges when shipping on mobile, along with key strategies for maximizing the creativity and flow in mobile games today.

Let’s start with the fundamental question: How do you characterize good UI in games?

Maja Nadvešnik: Good game UI helps create a seamless and enjoyable player experience, allowing players to focus on the game itself rather than struggling with confusing or poorly designed interface elements. For players to feel more comfortable and confident as they play, we as UI designers need to think about clarity, usability, consistency, and accessibility.

Benoit Dupuis: Good user interfaces in games must look attractive to the players and blend well with the universe or game fantasy they’re experiencing. They should be easy to access and use, present when you need them, but never in the way of enjoying the game. Whenever a UI feels glitchy or unresponsive, it starts interfering with the experience, so robustness and performance are also essential. Most importantly, they must be usable and readable, enabling players to interact with the various game systems and access critical information.

What is your process when creating the UI of a game? 

Maja: The process of creating game UI typically involves several steps, including defining the UI goals and requirements, sketching and prototyping, designing and styling, implementing and testing, and iterating and refining. In some cases, the UI may be created as part of a larger development process that can involve working closely with other team members such as artists, programmers, and producers to ensure that the UI is integrated seamlessly into the game or project.

How do you go about choosing fonts for your project? What about your color scheme?

Maja: The font and color scheme should be chosen to support and enhance the overall visual style and tone of the project. Since we mostly design for families, our projects are whimsical and creative, and we use more modern and vibrant aesthetics.

For our games, we choose playful fonts that are legible and readable. During the design process, we test and define the minimal readable text size. When we’re working on color schemes, we are inclined to use colors that fit the art director’s vision, have sufficient contrast, and work well together.

On average, how long does it take you to create the UI?

Maja: The time required to create the UI for a game depends on the specific needs of the project, as well as the resources and processes being used. Creating UI for our games starts in the preproduction phase, which lasts a few months. After preproduction, we choose the UI direction and continue working on polishing the UI and expanding it from the main gameplay to the side features. It can take six months to a year before we have a clear vision and fully define our UI style, and even then our work continues until the last feature of the game is ready.

How important is it to consider different hand and finger sizes for players?

Aleksander Gregorka: It’s an important consideration because children will interact with a device a bit differently than teenagers or adults, given the mixed audience of our apps. They hold it differently and sometimes they’re a bit awkward with specific gestures. They will also attempt all sorts of multi-touch actions, so you better be ready.

What we like to do is make our buttons big and easy to recognize. Whenever you need to select multiple things, they will be far apart from one another. When you’re dragging things around, we will shift them slightly upwards, so your finger doesn’t cover the thing you’re dragging. It’s important to be able to see what you’re doing without covering the screen with your hands.

Stefania Valoroso: Especially for mobile gaming, this is an important consideration and can largely depend on your target audience. For example, if you are building games for children who will have smaller hands than adults and maybe aren’t as dexterous, you’ll need to think about how gestures work, how specific users are in their movements, and where commonly accessed buttons and interactions are placed. It’s harder for a smaller hand to reach the middle of the device, let alone the corner opposite of where their dominant hand is usually placed.

Additionally, it’s worth considering how your users can customize the controls or UI based on their dominant hand used for completing interactions, or if it’s possible to complete that interaction in other ways for those who would like to play with accessibility tools. To dive deeper, consider how the design principle of Fitts’ Law – the time it takes to move to a target depending on how big and far away it is – might relate to mobile devices. For more information, check out this article from the Nielsen Norman Group.

What is your best advice for creating UI and designing for a UI-heavy game?

Aleksander: The most important thing is to be consistent. A button in one part of the game should behave and look the way it does in another part. Add some breathers to create groups of items that belong together. Avoid clutter and heavy animation on everything, focus on the most important parts that absolutely need to draw the player’s attention.

Søren Klit Lambaek: It is important that you carefully work out a system that is performance-friendly. Make sure you test your UI on a regular basis, on as many devices as possible. If you have any UI that renders on the fly, make sure that it only updates when absolutely necessary.

What are the challenges, added work, and benefits of designing a foldable UI?

Søren: In Unity, the support for foldable phones is very good, which means that the developer will not need to do a lot of legwork to support foldable devices. It is already built in the UI components, but the aspect ratio of the screen is a common issue to get right. The arrangement of the UI for the transition from cover screen to the large double screen on a fold phone can be tricky, so you will need to do some extensive testing on the devices.

What are some of the tools and resources available for designing foldable UIs?

Søren: Our team has written tutorials for the support of foldable phones using Unity. These tutorials are available on our developer website:

How do you approach animations in UI, while keeping the UI responsive?

Stefania and Benoit: Our main advice is to not overuse them. Motion is essential for making usable user interfaces that convey information, as well as getting the user’s attention, and establishing relationships between elements. In games, animations are also used for celebrating key moments, which can often require more elaborate graphics and visual effects, bringing a sense of reward to the player. It is preferable that they’re limited to those cases.

A good practice is to try and reuse small animations or transitions that are common throughout your UI. Not only does this convey consistency throughout your game, it also reduces performance issues. If possible, and depending on what you’re trying to achieve, knowing when to apply these standard animations through code alongside animation components will help your UI look great and react quickly while responding to changes in layout or orientation. Using UI Toolkit, you can take advantage of our USS transitions to add lightweight transition effects to your UI.

What are some of your UI design principles for encompassing different resolutions across mobile devices?

Maja: Using responsive design as an approach ensures that the layout and appearance of the UI adjust automatically to fit different screen sizes and resolutions. Working with flexible layouts that use percentages or ems, rather than fixed pixel values, can similarly ensure that the UI adjusts smoothly to different screen sizes and resolutions.

Can you share a few tips around UI design when targeting Samsung devices?

Søren: When it comes to foldable phones, make sure that the aspect ratio and resizing (the transition from cover screen to main screen) work as intended. If not, you will end up with unwanted results like missing UI or graphics that look wrong.

For foldable phones, I recommend implementing Flex mode as early as possible. As soon as that’s been implemented, the UI designers can play around with ideas and test them to see if they work as planned.

You will need to test your UI on as many devices as possible; Samsung provides Remote Test Labs for this, which can be used for free by anyone with a Samsung account.

What are some best practices for designing cross-platform UI?

Stefania: The first step is understanding how each platform affects the UI and controls, including placement, physical user interaction, expected behavior, and context. For example, moving a character around the world with your thumb on mobile is completely different than moving your character with your mouse and keyboard on desktop or a controller on console.

What does that UI actually look like in those contexts? Is it helpful to have the edges of the screen accept user input on a touch device – and therefore, a specific piece of interactable UI – or could that interfere with the swipe actions a user might make throughout their day while using their touch device, like swapping between apps or swiping to bring up quick device settings?

In terms of Unity implementation, you can utilize Prefab Assets or UI Documents that are toggled depending on the targeted platform. Using UI Toolkit, you could set up platform-specific Unity Style Sheets (USS) for initializing UI Documents, which could be surfaced as MonoBehaviours so that codeless workflow users can assign the USS they want for each platform. If there are large differences, you could do something similar by assigning UXML assets per platform via a component.

The main takeaway is to test on the device as much as you can to really get a feel for how users will interact with your interface on that specific platform.

What is your advice for making a decent mobile UI for both landscape and portrait orientations?

Aleksander: If you just port your portrait UI to landscape, it will look weird in some places. It’s better to actually design for it by moving things around. Landscape orientation allows you to move menus to the side, for instance, which enables you to see the game on a part of the screen, if you choose to allow it. I suggest you test it and observe whether the players are actually using it as intended. I can assure you that you’ll be surprised.

Stefania: Getting a feel for how your users are interacting with the interface in that specific context is key. It could be easy for a user to quickly touch centered buttons with their thumbs on portrait, but when the UI is switched to landscape orientation, it becomes less likely that they will accurately hit those buttons. They might need to move to the corner(s) for easier access.

Furthermore, elements that are anchored to a corner can have a fixed size in both orientations, and be refreshed as the Canvas changes. If an element needs to be repositioned, or requires a completely different interface depending on the orientation, you can utilize enabling and disabling elements based on the view.

How do you manage safe areas for UI design with different screen resolutions?

Aleksander: We treat safe areas as dynamic UI offsets. For each device, we get top and bottom offsets, or left and right for a landscape game, and we dynamically offset the UI elements.

Some of the main points for mobile designers to take away from this interview are to focus on a seamless, accessible, and enjoyable player experience. Designing for your audience and planning for consistency early on will help you throughout the design process, and beyond. In part two of this series, our experts will unpack insights on implementation, testing, performance optimization, and analytics integration for UI.

Want to know more? Read our new e-book on user interface design and implementation in Unity. We also invite you to share your tips for success with other users in our Made with Unity forum.

January 31, 2023 in Games | 16 min. read

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