Online firm Gravity discovers what Epic's game engine can do on iOS

Unreal Diaries: Developing Tower of Ascension on mobile with UE3

With sword-wielding warriors and spell-slinging wizards, fantasy role-playing and battle games are among the most popular mobile offerings, but few titles have been as ambitious as Tower of Ascension.

Published by Gravity Interactive, the North American arm of the Korean developer and publisher behind the internationally acclaimed Ragnarok series, Tower of Ascension is a free-to-play, action role-playing game that ventures beyond the status quo of mobile offerings to hook players with beautiful visuals, deep mechanics and fierce multiplayer battles on iOS devices.

“Our main goal was to create a mobile game capable of competing with high-quality, online PC games,” says Gravity chief technology officer Jinsoo Jeon. “Most large-scale games were only available for single-player, but we were determined to create a game of the highest calibre that could also deliver memorable multiplayer experiences.”

Gravity needed a game engine capable of pushing visual boundaries and incorporating online components for team-based matches. With a combination of first-class tools and unbeatable optimisations for mobile games, Jeon says: “Unreal Engine 3 was the obvious choice for realising such a project.”
He explains that visual fidelity was only one of Gravity’s concerns. With 120 skills for players to unleash, special abilities and reactions such as knock-backs and stuns, as well as an original control scheme, creating many features in Tower of Ascension required close collaboration across technical and artistic disciplines.

Unreal Engine 3 immediately proved its ability to provide exceptional optimisation results. This was a huge advantage, allowing us to put more time and resources into other areas of the project

– Jinsoo Jeon, Gravity Interactive

“Having a unified toolset was the most impressive and beneficial feature of Unreal Engine 3,” he says. “There were many functional and graphical demands made between programmers and artists throughout the development process. Being able to work co-operatively and fulfil the needs of both sides from within Unreal Engine 3 really helped increase productivity so we could focus on making an enjoyable action game.”


As a result of Unreal Engine’s one-stop-shop nature, a highly impactful benefit for Gravity was the ability to both develop and iterate directly in the same PC environment. Jeon adds: “Even though we were making a mobile game, we were able to quickly set up events in Unreal Kismet and then run tests directly on the PC, which was really convenient.”

Of course, creating a PC-quality game for smartphones and tablets presents unique challenges for even the most high-tech devices. Recent technological advancements have presented developers with the ability to create three-dimensional worlds and visual effects of unprecedented quality, but implementing such high-end features while ensuring a smooth gaming experience can be a delicate balancing act.

“Compared to desktop PCs, which can utilise components such as powerful GPUs, mobile devices have greater limitations in terms of system resources and functions. This is why optimisation is so vital to mobile game development. Unreal Engine 3 immediately proved its ability to provide exceptional optimisation results. This was a huge advantage, allowing us to put more time and resources into other areas of the project.”

Jeon was very enthusiastic when asked what advice he would offer to other teams considering Unreal Engine for their mobile game developments.

“Developing a rich, lasting experience requires effort from many groups, so it’s crucial to utilise a game engine that supports those groups while increasing productivity and avoiding any unnecessary complications. This is why we gladly suggest Unreal Engine to other mobile developers.”

Jeon adds: “Unreal Engine has a very well-organised community. Not only are we able to share our own experiences, we learn new techniques from other game teams and receive support directly from Epic Games when needed. It is a pleasure to be a part of that group.”

With the release of Tower of Ascension on the App Store, Gravity proves that ambitious ideas can become reality with the help of world-class technology.

To read all of Develop’s Unreal Diaries, visit our archive

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