AppLovin launches free tool to help devs migrate from Unity to other engines amid controversial Runtime Fee rollout

Mobile marketing and monetization platform AppLovin has launched a new project to help Unity developers switch to other engines like Unreal and Godot. It can already speed up code translation, and tools for asset and plugin migration are also in the works.

What is Project Unifree?

Earlier this week, AppLovin CTO Basil Shikin shared details about a new proof of concept tool in a blog post. “Over the last week we saw a rising interest in tools that allow migration from Unity to other game engines,” he wrote. “I want to share some thoughts on the technical aspects of the migration and propose a few approaches to simplify it.”

Called Project Unifree and currently available on GitHub (also spotted by GameFromScratch), the tool is based on the ChatGPT 3.5-Turbo model and is primarily designed to help Unity developers:

• Scan source project and detect files eligible for migration;
• Use the power of LLMs to translate Unity classes into scripts used by other engines (it currently supports Godot and Unreal).

A portion of code migration that translates Unity classes into GDScript (Godot’s high-level scripting language)

Although Unifree is already good at translating overall logic, the results still require manual tweaks. So it is more about creating a baseline to accelerate the migration process.

“I wanted to demonstrate that we can utilize modern LLMs to ease the transition between Unity and other engines and I think early results are positive,” Shikin said. “It makes sense, because fundamental game engine structures are similar, but language and APIs can vary a lot. This is exactly what LLMs are good at: generalizing and translating an idea.”

This comes amid the introduction of the so-called Runtime Fee, which implies that Unity would charge devs additional fees based on their game installs. Following the community backlash, the company said it will overhaul some aspects of its new pricing model. However, many developers have started considering switching to other engines due to a huge trust breach.

What are AppLovin’s plans for Unifree?

Other problems developers face when switching from Unity to another engine are:

• Migrating static assets (scenes, materials, sounds, etc.) — there are already existing tools for Godot, Unreal, and Cocos, but AppLovin plans to continue its research to make a tool that would be “reusable across multiple studios and projects”;
• Migrating plugins — this is a complex task given a rich ecosystem that Unity has built over the years, but AppLovin hopes that its tool will eventually be able to help devs port their work to other engines.

AppLovin used one of the open source Godot plugins to migrate a static asset from Unity (left) to Godot (right)

Shikin noted that once the team implements static asset migration and improves LLM prompts the Unifree tool “has the potential to help hundreds of developers ease the daunting task of re-writing the entire game from scratch on a new engine.”

Right now, AppLovin is focused on three engines, Godot, Unreal, and Cocos. So it is calling on the community to help it improve the tool by reviewing ChatGPT prompts, adding static asset migration tools, and making Unifree easy to run for new devs across various OS.

As of now, AppLovin warns that this POC project will “help aid migration by providing you with a base, but you will have to modify a lot of code yourself.”

More information can be found in the blog post and GitHub.

***

Last year, shortly after Unity first proposed a merger with ironSource, Applovin offered to acquire the engine maker for $17.5 billion. However, Unity rejected it, eventually completing its ironSource deal.