Unreal Engine 5: How is this even possbile?

[tlf30]

A first look at Unreal Engine 5

How are they doing this, it looks like an April fools joke in May. How can this be possible in real time?

[Ali_RS]

Yes, I also saw that.
Triangles in the size of pixels…

They said demo was running on PS 5, might be something about hardware as well?

[The_Leo]

@tlf30

How are they doing this, it looks like an April fools joke in May. How can this be possible in real time?

Which part of it? The triangles? If you listen carefully, they tell you that there are 1b tris, but only 20M are rendered. So as to how. The obvious answer would be some sort of LOD/Custom datastructure is used. However, they still need to store the huge scene, so the game assets would take lot of disk space if they used that many triangles. But it may be that many of the rocks are ‘instanced’/share vertices anyway, in which case it is simply LOD.

[8Keep123]

They use a virtual texturing system, so maybe a custom virtual memory system for meshes as well?

[jayfella]

It’s a tech demo. And it’s extremely impressive. But it’s not indicative of actual releases gameplay. But still. Wow. Same as this video.

Star Wars: Reflections | official Unreal Engine real-time ray-tracing demo (2018)

[fba]

New GPUs ray tracing capabilities also counts to make things look so good.

Introducing the NVIDIA RTX Ray Tracing Platform

AMD's Raytracing Exclusive To High-End RDNA 2 Based Radeon RX Navi 2X Cards,...

[NikolayPlekhanov]

Nanite

“The vast majority of triangles are software rasterised using hyper-optimised compute shaders specifically designed for the advantages we can exploit,” explains Brian Karis. “As a result, we’ve been able to leave hardware rasterisers in the dust at this specific task. Software rasterisation is a core component of Nanite that allows it to achieve what it does. We can’t beat hardware rasterisers in all cases though so we’ll use hardware when we’ve determined it’s the faster path. On PlayStation 5 we use primitive shaders for that path which is considerably faster than using the old pipeline we had before with vertex shaders.”

Lumen

“Lumen uses ray tracing to solve indirect lighting, but not triangle ray tracing,” explains Daniel Wright, technical director of graphics at Epic. “Lumen traces rays against a scene representation consisting of signed distance fields, voxels and height fields. As a result, it requires no special ray tracing hardware.”

To achieve fully dynamic real-time GI, Lumen has a specific hierarchy. “Lumen uses a combination of different techniques to efficiently trace rays,” continues Wright. “Screen-space traces handle tiny details, mesh signed distance field traces handle medium-scale light transfer and voxel traces handle large scale light transfer.”

Lumen uses a combination of techniques then: to cover bounce lighting from larger objects and surfaces, it does not trace triangles, but uses voxels instead, which are boxy representations of the scene’s geometry. For medium-sized objects Lumen then traces against signed distance fields which are best described as another slightly simplified version of the scene geometry. And finally, the smallest details in the scene are traced in screen-space, much like the screen-space global illumination we saw demoed in Gears of War 5 on Xbox Series X. By utilising varying levels of detail for object size and utilising screen-space information for the most complex smaller detail, Lumen saves on GPU time when compared to hardware triangle ray tracing.

Inside Unreal Engine 5: how Epic delivers its generational leap

[1000ml]

““Lumen traces rays against a scene representation consisting of signed distance fields, voxels and height fields.”
Sounds a bit like what people do on shadertoy.com plus Bresenham’s line algorithm for rays in a voxelized scene.

[JhonKkk]

I am currently engaged in BIM development. ifc or rvt models rendered at 60 frame rates are billions of triangles. However, the most basic illumination is used and there is no texture sampling.