Unreal Engine 5 recently emerged from early access, with a full version now available to games creators. Simultaneously, the ‘city sample’ portion from the brilliant The Matrix Awakens demo was also released, giving users a chance to get to grips with MetaHuman crowds and large-scale AI in a vast open world, with buildings, roads and more created via procedural generation. In short, Epic is opening up a staggering wealth of new technologies to all and UE5 is, effectively, the first paradigm shift in games development seen since the arrival of the new consoles. So what have we learned from this release? Put simply: it’s demanding. Very demanding.
At this point, it’s worth highlighting why the city sample is so special – and it’s pretty straightforward. Creating and rendering cityscapes of this level of detail is no walk in the park. Previous UE5 demos had been limited to linear, uniform, rocky landscapes. A city like the one ‘given away’ here is far more complex in terms of materials, shapes, forms and dynamism. The Nanite geometry system gives extreme detail to the smallest elements in the city – to the point where individual tiny assets can look almost lifelike when viewed up close. Nanite has its limitations in terms of deformable meshes like animated characters or cars, while integrating elements like foliage is still work-in-progress (though it is definitely in the pipeline!). However, the results in this demo speak for themselves.
Then here’s the global illumination system – Lumen – now updated with support for hardware triangle ray tracing for diffuse GI and reflections. In some scenarios, Lumen’s non-RT fallback systems look almost as good, but in other situations, it’s clear that RT can make a huge difference – reflections are more accurate and detail-rich, lighting is so much more accurate, especially noticeable in night-time scenes.
Epic is pulling out all the stops here – and right now at least, the performance implications can be startling. First of all, there’s the issue of shader compilation stutter – a problem with UE4 titles on PC for some time now and massively impactful to any initial run through the city sample, no matter how powerful your PC. Once the stutters subside (which they do, the longer you play the demo), it quickly becomes obvious that even a highly capable CPU is struggling with the content. A Core i9 10900K at 5.0GHz locked paired with an RTX 3090 can see a performance average of around 44fps in a fairly taxing scene – and that’s at native 720p rendering, attempting to remove the GPU as a limiting factor to performance. Moving at speed through the city sees sharp frame-time spikes: further stutter that seemingly isn’t shader compilation limited.