[9] However, this feature, called Sparse Voxel Octree Global Illumination (SVOGI) and showcased with the Elemental demo, was replaced with a similar but less computationally expensive algorithm due to performance concerns.

For a monthly subscription at US$19, developers were given access to the full version of the engine, including the C++ source code, which could be downloaded via GitHub.

[31][32] According to Karis, Epic "decided to invest some time in improving [UE4's] shading model and embrace a more physically based material workflow".

[31] Parameters omitted from Disney's model were "Specular," "Subsurface," "Anisotropy," "Clearcoat" and "Sheen," which are instead treated as special cases.

With Unreal Engine 4, the effort is to expose at the base level everything in a very simple, easy-to-use, and discoverable way and to build complexity on it so that the user can learn as they go".

[34] With Unreal Engine 4, we really want to be able to build an entire small game on the scale of Angry Birds without any programming whatsoever, just mapping user input into the actions using a visual toolkit.

We're just greatly simplifying the interface so that it's basically as easy to use as Unity.In line with UE4's focus on simplicity, it included a new visual scripting system called "Blueprints" (a successor to UE3's "Kismet"[35]), which allows for rapid development of game logic without using code, resulting in less of a divide between technical artists, designers, and programmers.

It means I can really go in and start enhancing my world with interaction that just would not have been possible without a technical artist, a designer and a programmer and now any one of those three can do all of it, provided they have the assets handy.

And he wouldn't have known how to set up the assets, but now any one of the three could do it.On September 4, 2014, Epic released Unreal Engine 4 to schools and universities for free, including personal copies for students enrolled in accredited video game development, computer science, art, architecture, simulation, and visualization programs.

[43] Sweeney stated that when they moved to the subscription model in 2014, use of Unreal grew by 10 times and through many smaller developers, and believed that they would draw even more uses through this new pricing scheme.