Unreal Engine 5 Tech Demo, [UE5 Developer Availability 2022-04-05]

The idea comes from Microsoft R&D and everyone need to read this for understand how they did. This is clever.

http://hhoppe.com/proj/gim/

They solve the tiny triangle problem @Dictator , the idea was there but not the hardware

http://graphicrants.blogspot.com/2009/01/virtual-geometry-images.html

 

@iroboto Maybe the renderer is entirely compute driven and the rasterizer is skipped entirely. If you generate some data structure that's culled down to 1 triangle per pixel, that what is the triangle coverage test for? You know which primitive covers that pixel, especially if you're doing primary ray tests. You probably only need to know which texel plus material data maps to that triangle, and the surface normal.

 

https://forum.beyond3d.com/posts/2125480/

Read my post they don't need have the problem of tiny triangle anymore

 

I thought I read that that solution was one of the inspirations but not the solution they settled on. Curious to see where they went, but my guess is it ends up settling the small triangle problem in a similar way.

 

Great add will review later tonight.

 

They mentioned deformation though.

We don't know if the PS5's raw geometry performance is the same as Navi 10's, or if they really meant 1 triangle-per-pixel.
But if it's 1 triangle every 16 pixels, then the PS5 at 2.2GHz should have a 140.8 GP/s fillrate. Divide that by 16 and you get 8.8 GTriangles/s.
1440p is 3.7 MPixels. At 30 FPS, you need to be able to process 3.7 x 30 triangles = 110 MTriangles/s.

Unless I made some miscalculation somewhere, it seem that triangle throughput isn't the bottleneck for 1 Pixel = 1 Triangle which in theory should be good even for 4K120, but rather triangle culling (or of course some other factor I'm missing here).

 

Basically this solution should provide perfect lod and eliminate edge aliasing entirely. TAA should only be needed to remove shader aliasing. Low resolutions should actually look much better than they would in a typical rasterizer.

... I think.

 

I hope on the PC side of things we are able to use main ram as a buffer. Ram is pretty cheap , I have 32 gigs of main system ram. If an UE5 engine game would use my nvme drive plus 16 gigs of DDR4 that could enable some pretty amazing things I would think.

 

@eastmen Yah, that's one way to overcome some of the nvme performance differential to ps5. Keep way more stuff in RAM. Hopefully they have a number of options to make the best of various different hardware configs.

 

I assume they can make a slider like a texture one now to affect the quality of the meshes. Or even have one that devotes system ram. If games made use of it I would buy 64 gigs of ram. Devote 32as a streaming buffer plus a Pci-e 4 nvme drive. In 2021 I am sure we will see faster than 6GB/s drives in pc land and there is nothing stopping performance mobos with pci-e 4 8x for 16GBs.

Would love to see what this tech can do pushed to its maximum

 

Really curious to see if they'll demo it with Nvidia whenever consumer ampere launches. If it supports DLSS 2.0 they'll get easy wins in terms of lowering the amount of texture data, geometry data they need to stream in per frame because with this solution it looks like pretty much everything scales somewhat linearly with resolution.

 

I would like to see some grass and trees. I'm waiting for them to say, grass is rendered differently so you'll still see grass popping in twenty feet ahead of your player.

 

Seeing all thoes polygons I assume they have to cull loads from out of sight geometry,



Using mesh shaders which I assume is happening on next gen.

Also the idea of loading "film" assets seems to tie with other work flows Unreal have been perusing.



Funny people mention star wars as I suspect a fair share of asset reuse here.

 

Would using Nanite solely for environment and non character models potentially drastically increase polybudget for animated character models?
Also next gen jungle/forest would look so real that you might literally get lost in the level lol.

 

This is best we have at the moment.
Amiga 500 1MB of memory.

If shading is moved to object space, shader aliasing will certainly be quite different problem to what we have used to.

 

It should be noted that it currently looks like Lumen only casts hard-edged shadows which everybody hates & has been trying to fix or is fixing for decades with contact hardening etc.

 

you do not have infinite GPU ressource sadly, and seeing how we still see some polygon edges on the character in the demo, they are still limited by some factors.

 

Ue4 already have auto LOD generations so you just plop your high model and there will be lod 0,1,2 generated.

But with ue 5, it seems the lod will not be distinct quality like lod 0,1,2,3 but It will be gradual. So no weird lod transition / pop

 

Awesome stuff!

 

It’s 1 triangle per primitive engine. There are 1 primitive engines per shader array or 2 per shader engine. So total 4 triangles per clock and 64 pixels (ROPS).

So you're doing 4 triangles per clock, actually. But that is optimal triangle/pixel emission. The number can actually go down. And it will go down as you go below the thresholds like 1 triangle and exponentially worse once you get into sub pixel sizes. This blog illustrates this well

So using simple triangle fillrate test, the tiles are primitives, so they should divide into 2. Starting at 1 tile of 1080p, and shrinking to 1x1 pixels. You can see at tile (1,1) Performance has completely fallen off a cliff.


Subpixel performance becomes an exponential graph the smaller the triangle is. WRT to what we saw, UE5 is at 1


So we used optimal numbers which was wrong, it's simply not possible to do small triangle per pixel performance using fixed function pipeline, at least not in the traditional sense. They must have done something entirely different, and I suspect UE5 is a very heavy compute based pipeline.