Folks, is it possible to use only certain C++ parts of the UnrealEngine in my project? I’m mostly interested in renderer.
We are a small team and we already have lots of our own C++ code. We have our infrastructure and tools setup and we are pretty happy about it. What we really need from UnrealEngine is its 3D rendering capabilities. Is it possible to use only this part of the engine? We don’t really need to use the UnrealEngine editor…
Sorry…You cannot copy any of the Unreal code. You can learn from it but you should not copy it.
Here is what the FAQ from Unreal Engine site says:
Can I copy and paste the Unreal Engine code into my own project or engine?
If you use any Unreal Engine code in your product (even just a little), then your entire product is governed by the EULA, and royalties are due.
Can I study and learn from the Unreal Engine code, and then utilize that knowledge in writing my own game or competing engine?
Yes, as long as you don’t copy any of the code. Code is copyrighted, but knowledge is free!
But…if I’m going to pay 5% from the game revenue…does it still apply? And going back to the question, is it technically possible to use just the part of the engine?
All modules are very tightly connected. You would be better of studying on how Unreal does it. It’s a mix of some clever coding and good use of shaders. Start by looking at the shaders, then jump into the code and see how all the constants are set in those, etcetera. You’ll eventually get an idea.
Hi bitgames,
What ryanjon2040 has said is correct. As long as you don’t mind the royalties (5%) and obeying the EULA - feel free to include all or a portion of the code base. Though I’ll give you fair warning - our renderer is awesome but the tools are the life blood that feed it. So much of the renderer is dependent on the tools pipeline we’ve created. Things like our material editor are what allow artists to make our renderer shine. Trying to hookup a completely different set of tools to it may prove difficult without copying large portions of our tools pipeline as well.
So - I might offer an alternative. If you like your tools, consider augmenting ours. The UE4 editor is really pluggable, so instead of trying to take our renderer out - you might could try adding your tools to ours.
Cheers,
Nick (Epic Games)
Sounds reasonable, considering biz and legal affairs. We here at KTX and SYA are intersted especially in the ingame capturing/gameplay-recording feats that comes with the engine, and we think about building a workflow with that.
Please do!
Thanks, it sounds like a plan. Where can I read more on integration of the existing codebase with UnrealEngine? 
We’ve got some plugin documentation here,
https://docs.unrealengine.com/latest/INT/Programming/Plugins/index.html
And there is lots of general information here,
https://docs.unrealengine.com/latest/INT/Programming/index.html
Once you have the source code off github, I would look at some of the plugins we ship in the “Engine\Plugins” directory. The “PluginsEditor” is actually a plugin, which makes me smile. There’s even an experimental 2D Engine plugin here Engine\Plugins\Experimental\Paper2D. That will probably have the most example code for making real tools plugins that integrate with our asset pipeline.
Cheers!
Nick (Epic Games)