UE doesn’t support SLI or similar technologies yet btw.
There is no mention of multi-GPU on roadmap and besides the tech demo made by Epic for NVidia and Disney at last year’s GDC for RTX where it was possible, it was not built into an specific engine release, so it might happen or not, we just don’t know, there is nothing yet that confirms this is being built for 4.22. Since the engine is being marketed for film production, we assume this as a “must” feature.
Maybe we could have some word from @kenpimentel if we are going to see multi-GPU support and if so, when?
The new version of SLI is a little different in that connected cards automatically pool their video memory with or without support for SLI, so there’s definitely some hope.
Nilson, thanks a trillion for your detail explantion for the dummies. Will try and post some shots later. Is this build being updated almost everyday?.. I guess I have to redownload and recompile every week or so huh.
yes I know ue4 doesnt support multi gpu yet… but I bought two so that I can use it with redshift, octane, arnold gpu (when it comes out) and possible use of Nvlink when some or all of the mentioned renderers start supporting nvlink for 22gigs of ram from two 2080tis.
it would be nice is ue4 eventually supports multigpus since that would allow faster fps and more complex scenes. 
thanks again.
I did what was explaned by Nison, and I don’t see any Raytracing option in the viewport “Lit” menu, and I can’ see any soft shadows in the viewport with rectangular area lights.
As for archviz indoor/outdoor testing, I have done some related tests. Shadows are very good. They are no different from traditional ray tracing shadows. Reflections are also very good, but the performance consumption is slightly higher. AO’s effect becomes acceptable after adding noise reducer. There is no big problem to achieve the same accuracy as traditional offline rendering in three aspects: AO, reflection and shadow. However, because GI is still not supported, important GI effects can not be seen in the test, but according to several other modules, using DXR to achieve near-offline rendering level is not very difficult, ray tracing is no longer a problem, the only limitation may be that the rasterized hybrid rendering will have a slightly worse rendering accuracy.
And the path tracking mode has some support (although there is no noise reduction function, the overall operation is very slow), the quality of the path tracking is very high, almost as good as most offline renderers. It is expected that the mature path tracking mode can complete a high-quality static frame in tens of seconds?
Because of some problems, I can’t release the test image, but it can be seen from the test that DXR is indeed a cross-era technology that can disrupt many industries.
I expect path tracing will become the next big thing near the end of this generation of cards, it just needs time to mature and for wider adoption.
So, has anyone tried DXR on a 1080Ti? How was the performance versus a 2080 Ti?
Should 1080Ti not support DXR at present? NVIDIA has not released drivers that allow non-RTX graphics cards to support DXR operations. And even if 1080TI can be supported, the computational efficiency may be very low, 1080TI light efficiency tracking efficiency is only about one tenth of 2080TI. In terms of path tracking mode, the current 2080TI can barely maintain 10 frames to ensure the movement of the lens, and then tens of billions of light operations per second are required to calculate an image with less noise in tens of seconds (of course, without a denoiser), so I can’t believe how inefficient 1080TI will be.
I’ve heard that anything from the 10x0 generation can also do DXR but it’ll be slow, I’d like to confirm it though.
There are optimizations for path tracing like what Brigade uses, but I don’t think that product is realistically going anywhere. Temporal reprojection and denoising is basically the fix-everything hammer for performance now.
You also need to set at the console the raytracing and skin cache features, the raytracing I know is: r.RayTracing = “1”, but I don’t know which is the command for skin cache.
Why dont try glass material ??? Please try glass
They’re checkboxes in project settings. Do Skin Cache first then Raytracing. Then restart the editor.
Yes, I already checked the skin cache first and Raytracing in the project settings…
Is this correct on the target field of the shortcut for the editor?
“D:\Program Files\UE4\UE422\Engine\Binaries\Win64\UE4Editor.exe” -dx12 -raytracing
Should there be the quotation mark at the beginning and after UE4Editor.exe? if I take off the quotation after UE4Editor.ext then it tells me path is not correct and I can’t close the property window.
I compiled the UE4.22 to my D drive instead of my ssd C drive because of space running out. could be this why I am not getting the raytracing to load?
I also get this error when opening a test file by double clicking the shortcut (two rectangular lights over a sphere):
Assertion failed: !TotalBytesRequested [File:D:\Program Files\UE4\UE422\Engine\Source\Runtime\D3D12RHI\Private\D3D12Allocation.cpp] [Line: 1749]
That all looks correct. I also get some assertions at startup but I’ve been able to ignore them… right up until I updated yesterday and now my engine build no longer works.
If you go back to the commits done before Thursday/Friday then you should be good, but it looks like someone merged master into dev-rendering so that’s a wee way back in the log. I’m going to try commit 1ff2be8ed09e46179954ff7a5ab66a2ca4495199 to see if that one is stable.
Note that even when it was building and loading some of the build tasks failed. These can be ignored, but it also looks like it ONLY works with a fresh project. No earlier project upgrades. I had no problem injecting marketplace content though.
Landscape Objects seams to be ignored from Raytracing. Can someone confirm this? thx
That’s correct. Landscape is not implemented yet. It is unlikely to be supported before 4.23.
Will Multi-GPU targeted on a future release?
Will 4.23 be the release where all Raytracing features will be completely integrated or will there still some work after this release?
Can someone please try the ray tracking ao, reflections, shadows (all at the same time) with a VR headset in the editor. I’m just curious as to if it would even work yet?
Could be pretty great to mess with once the new “Vive pro Eye” releases soon. To increase the performance even more with the foveated rendering capabilities.
Tried it, it doesn’t work yet. The display is completely messed up.
I HAVE 1060 6gb
so i cant use dxr completely ?
this Raytracing supports multi bounce or not ?
the videos of this feature are to dark !!!