Differences between Unity and Unreal

Let's rephrase here a fundamental question. I'm considering using Unreal, but many people seem to be using Unity for making indie games. I'm never planning to go into AAA games, I only want to make...

Updated over 4 years ago

Let's rephrase here a fundamental question.

I'm considering using Unreal, but many people seem to be using Unity for making indie games. I'm never planning to go into AAA games, I only want to make indie games as a solo developer(maybe in a small team). Is Unreal the right choice for me? Does Unreal have significant disadvantages compared to Unity for an indie dev or a small team? Is it slower/harder to make prototypes and small indie games in Unreal? Why do so many people use Unity instead?

Well, there are a lot of comparisons on the internet. This is just a short summary which should give you some basic overview, so you would know better what to look at.

Unity is great for 2D games, mobile games

  • Unity shines at mobile development, lightweight on phones. Small engine footprint, even now possible to embed the Unity app in another app.

  • Unity now supports every mobile monetization method possible (ads, in-app purchase) - they focused for years on it.

  • Unity is much better for 2D games. Unreal support is very limited, it has only Paper 2D plugin. Yes, a single plugin and nothing around in the engine is designed with 2D in mind. Even the orthographic camera doesn't fully work with Unreal's lightning. Meanwhile, Unity provides a lot: 2D lightning, animation tools, sprites, tilemaps. Read more about the evolution of 2D tools in Unity.

  • Lightweight mobile games is a major reason why there are more Unity games published than Unreal ones. There are over 4 million apps on App Store alone.

  • Unity is all about being "simple, easy to start and universal".

UE4 is designed for small teams

This is the myth that Unreal Engine is meant for large studios. It's essential to debunk it here.

UE4 was designed with indie teams in mind as Epic already filled "AAA studio niche" as it was possible at a time. That's why we have blueprints, visual scripting and dozens of tools working with each other out of the box. Especially if somebody working on a game when gameplay uses characters or heavily-directed content (implementing and scripting small things in every place of the game instead of relying on programmer every day).

Check examples of solo devs and small studios utilizing the engine - links to blog posts on the official blog.

How much engines cost?

  • Unreal Engine is now free to use. And you don't pay anything until you reach the first $1 million game revenue!
  • Unity's personal license is free, but it comes with some limitations. Check their plans and pricing.

Tools & learning curve

  • Unity's easier to start with. It's an easier engine because it's much simpler. Fewer systems/features than UE4, it's easier to comprehend.

  • There's less learning of Unity since this engine doesn't provide reach gameplay framework out of the box. The built-in Unreal gameplay framework is used commonly to create games focusing on characters. First-person perspective, third-person view, but also top-down. It simply comes with character movement, character-oriented camera manager, advanced animation system.

  • The thing above doesn't matter much if your game doesn't utilize 3D characters. Or you prefer to establish your own gameplay framework from scratch - "make engine your own".

  • The issue can arise in Unity if you'd like to do something complex/advanced. It's often much harder with Unity. And we're not talking about "AAA complex level" - such division doesn't truly exist. There are no "indie features" or "AAA features". Every project uses a different set of features. You might not need 90% of Unreal features, but you might need all complexity and flexibility of a single system, i.e. Sequencer - saving a lot of time and effort while working on animating things in your world.

  • Unreal provides AAA tools for many domains out of the box. It's relatively easy to work with physically based rendering and achieve "AAA indie" quality. The engine comes with visual scripting and many similar node-based editors. Built-in animation systems are the best if comparing publicly available engines (i.e. UE4 is the first choice for fighting games). The list of tools and features provided with the vanilla engine is really long...

  • It makes UE4 very friendly for artists and designers. The engine philosophy is to provide all the standard tools. That's why it's so huge piece of software and it can be intimidating for beginners. You don't need to learn everything, just learn what you need for a given game. And you don't programmer to start since you got node-based editors everywhere in the engine.

  • Unreal Engine 5 promises to bring huge workflow updates to 3D artists. No more retopology of meshes, creating a low-poly version, generating LODs and baking normal maps.

  • Now, Unity is in process of adding fundamental tools to the vanilla engine, i.e. visual shader editor, input management. That's why the Asset Store is so vital for Unity, the engine was missing so many things. Still, there's no visual scripting - Unity acquired Bolt as a temporary solution, but their native solution not ready yet.

  • Nobody uses Unity's networking (they working on a brand new solution), relying on third-party solutions. Meanwhile, UE4 comes with the excellent multiplayer support out of the box. Unreal's gameplay framework is built with networking in mind. Gameplay Ability system is a framework preventing you from reinventing the wheel while building multiplayer mechanics.

Programming

Unity is friendly for programmers or maybe "scripters" would a better world. C# is easier to learn than C++, although... you don't use pure C++ for UE4. Writing C++ code for UE4 is much, much easier than regular C++. Actually, it's more similar to Unity's C#.

  • Epic built a multiplatform C++ library, tailored for game development. This is the engine's core. Something we often simply call "Unreal C++".
  • Unreal C++ provides its own libraries supporting math, vectors, strings... many of standard things just to make development easier.
  • It provides low-level mechanism like garbage collection or reflection, that you don't need even fully understand, but you gonna take advantage of it every day.
  • Writing code is simplified, thanks to dozens of built-in class, function and property specifiers. Also macros and many utilities.
  • Epic integrated Live++ to all developers since 4.22 - it allows you to quickly recompile changes in .cpp files. Even if the game is running! Super sweet.

If someone wants to be a programmer, shouldn't be much difference for him. Albeit learning curve for Unreal C++ is steep, partially because official docs don't explain programming/C++ concepts - assuming everybody is programmer already...

  • It's very important to use plugins like Resharper C++ with Visual Studio. It's not the fault of Unreal, Visual Studio tools don't handle C++ well. Especially large codebases like game engines. It's standard for a C++ programmer to not rely on Intellisense tool provided with Visual Studio. Read more on efficient [Setting up Visual Studio for Unreal Engine].

  • For those looking for an even better tool than Visual Studio, Rider for Unreal Engine is coming. And it's preview is already praised by many programmers. There won't be a free version, however.

  • You need to set up some kind of "build system" for UE4 if going serious about C++ with Unreal or having 2 programmers (you need to compile C++ and then open UE4 editor, no magical compilation in the editor like in Unity). It's nothing difficult, and you need that for another sweet thing...

  • UE4 source code is available publicly, free of charge. You can make use of that for years, without paying anything. Access to source code it's important, you can easily alter small things in the engine - improve tools, workflows, fix bugs. As every single game engine could have some critical bugs - you can fix in UE4 if it's important releasing, i.e. while releasing a game.

PS Epic purchased company behind SkookumScript for a reason. This a speculation, but they might come up with a custom scripting language designed to fill a gap between blueprints and C++. And that would serve us much better than just stitching another general-purpose language to the engine.

Stability of technology

  • Unity company doesn't create its own games and you can feel it. If you would work on the game, things from mentioned in the point above would be added a decade ago. Meanwhile Epic dog foods every single system. Either with Fortnite (so systems and editor tools tested game played by hundreds of millions of people on every major platform) or a special game developed to prove new systems (i.e. RoboRecall for VR). And this might the most important thing, UE4 tools are proven and often simply work. Meanwhile, Unity does usually create a promotional movie and doesn't even release it as a project - it's confirmed that some demos used renderer features that weren't implement in the engine afterward. For these reasons, we haven't ever seen a game that looks as good as Unity's internal demo.

  • A lot of indie studios switch from Unity to UE4 for the next project because Unity wasn't enough for more ambitious projects: more content, higher visual fidelity, multiplayer. A notable example would be InXile switching to Unreal for Wastelands 3.

  • Unity is in process of upgrading the entire engine for bigger projects and teams, but this an enormous undertaking... It means the engine goes through huge architectural changes and some studios decide its too unstable for developing 3D games. This is Reddit discussion under the opinion of Rust creator on the current state of Unity.

Unreal editor requires a better hardware

  • The Unity editor has low hardware requirements, but it won't run much faster on beefy hardware. It's great to make small games on a laptop, bring it to co-worker space or anywhere. Not so great for projects with a lot of code and assets, Unity won't scale that well.

  • UE4 requires more powerful hardware as it targets 3D games. It might get expensive if you're about developing the hi-end 3D game on a laptop. Check article on Recommended Hardware for UE4. In return, the engine handles asset-heavy projects way better than Unity. As engine targeting AAA since the beginning of time - it's optimized for crunching gigabytes of content. Engine fully utilizes even 128 thread CPU for things like code compilation, shader compilation, cooking game. Now Epic is in process of upgrading engine for open worlds, that already brings performance and workflow benefits for smaller teams.

  • It's a huge productivity boost to use two screens with Unreal editor. It wasn't optimized to use on a single screen with resolution lower than Full HD.