Unity3D or Unreal Engine 4: Which is Better for XR Development

There are a bunch of game engines out there (Sumerian, CryEngine, plethora of internal engines, Open Source, etc..) that are being used for XR development (btw, I’m using XR as an umbrella turn for ar, vr and mr, or whatever is coming up next :). However, 90% of developer, creators and engineers use either Unreal Engine 4 or Unity 3d.

Both great because they are easily accessible and both are known to be used in gaming projects (including XR).

I’ve spent a few weeks to research what are the differences between the two and which one is better suited for someone who is looking to start developing in VR or AR.

Of course, I’ve stumbled upon a few myths already. I’m going to cover the basics here but there’s a full 3000+ word comparison article as well. This is going to be more of a TL;DR part.

?? 1 - Interesting Stats

Unity

• 60% of XR content (and 50%) of mobile games are made with Unity3d
• 25 supported platform (from mobile, all XR headsets, Nintendo Switch, etc.)
• 24 billion installs in the last 12 month (you heard that right. Billion, not million)

Unreal Engine

• Prevalent in AAA game productions
• 15 supported platforms
• 7 million users in the design and enterprise community

?? 2 - Infrastructure

One of the important things when starting any kind of development (including XR) is the fact that you’re going to have to learn a lot by yourself. This means you need to have access to the documentation, asset libraries and community.

Libraries Unreal Engine has around 10,000 assets in the store while Unity has five times as much (31,000 of 3D assets alone)

If you’re starting out, it’s great to have a collection of resources so you can just drop into your scenes. Having more models to choose from is great, however with Epic has just released a Quixel Megascans pack with 10k high-quality material. This is a huge deal!!!

At this point, regarding libraries, I’d say they are about even.

Documentation and Training

Being on the scene for multiple years, both Unreal and Unity3D have extensive and well-developed documentation. There is a difference in education possibilities.

On Udemy alone, Unity have 5,500 possible courses, while Unreal have 2,200. It shouldn't be a big deal since quality of those courses is more important than sheer number. Most of those are focused on gaming.

Community

Both engines have their forums where developers help each other break through the issues. UE has about 12,00- topics on C++ and 4,600 threads on XR development while Unity3D have 128,000 threads and 6,100 topics on VR developments.

/r/Unity3D/ 159k members

/r/unrealengine/ 66.9k members

There’s a slightly better chance you’re going to find an answer on Unity.

??3 - Development Process

Perhaps, the biggest difference between the two engines is that they utilize different programming languages. Unity’s primary language is C# while Unreal is a choice between C++ and Blueprint visual scripting system (for non-programming developers)

Debates on which one is better are meaningless however, C# code is a bit simpler and more accessible for complete beginners. You could use Blueprint’s node-based approach however your performance might suffer.

Unity has a slight edge here.

??4 - Source Code Access

Here’s where the major difference lies. Unreal Engine is an open source engine. Unity3D is not (at least not without an expensive enterprise license).

This is often a deal breaker for bigger productions where they want to have as much control as possible. For smaller teams it’s not a big of an issue since in most cases you don’t need to touch the source code at all (if you do, you should definitely know what you’re doing)

??5 - Graphics

Unreal’s reputation leans on the graphic quality and it’s well deserved. Back in 2012 when it was first revealed the graphic was unprecedented. And c’mon… seeing Quixel megascans that just released it would be hard to distinguish them from a high resolution photography.

But Unity came a long way since 2012. It’s capable of creating photorealistic scenes as well: Here’s a head-to-head comparison between of graphics in one video.

Some developers say that Unreal does look better out-of-the-box but that just means you have to do some tweaking in Unity.

Unreal Engine is slightly better in this department but there is one caveat. If you are to build scenes using Blueprint node system you may encounter performance issues. The code just isn’t as polished as if you’d be doing it from scratch.

Conclusion:

Both engines are great for XR Development and you wouldn’t go wrong with either of them. If you have experience in C++ than UE is great. If you don’t have coding knowledge at all than Unity is a better start because of simpler code and amount of support there is out there.

If you’re developing an app for a particular platform, Unity might be the only choice.

If you really need control and polished graphics out of the box then Unreal is a better choice.

I would encourage anyone to study both platforms, Hope this short summary does break some myths around both engines though.

P.S.: I do have some notable projects in the comparison guide for both in the full article (more from XR non-gaming projects)

P.P.S.: If anyone used both engines for a 100+ hrs, I’d love to hear your opinion.