Unreal Engine 4.23 Preview

[Leo Rakes]

If you've not already, please report any issues you find that have regressed or are "bugged" from intended or expected behavior so they can be properly investigated and reported where possible.

As for LPV and SSGI, these are both experimental and unsupported features. SSGI is not yet ready for production and is not a feature we're focused on marketing or calling out for the 4.23 life-cycle. It's expected to be ready for 4.24, so expect to run into issues and incompatibility with other features.

For LPV, this is not an actively developed feature and any regressions are expected since we've been doing a lot of changes in rendering lately. These may or may not be resolved in a future release. It's not a feature being actively developed by our Rendering teams.

It looks like this. In fact, RT AO, RT Shadow are already very good. RT reflection and translucency are also good. But if we want to run in real time, we still need a GI with good effect and excellent performance. SSGI looks like the future direction. It seems that it is very difficult to find a good real-time combination effect in 4.23.

By the way, SSGI in the previous rendering branch seems to be able to fuse RT effects properly, but not now.

[fathandanklowor]

How to use this ?

Remote Control over HTTP

[Crazy Rabbits]

Will ue4.23 copy the data table row, this is a very useful and great feature, because countless data to add, very cumbersome, very grateful

[Daffrendo]

Ok, on RAYTRACING-

While Raytracing, in any mode, be it with GI or not, be it with shadows or not, be it with high samples/low samples....anything:
You get a full-mesh raytraced shadow for translucent opacity-mapped meshes. So, the texture looks mapped, but the shadow is of the full mesh.


(Pic 1 - Sparrow 4.23 Preview 3)
Paragon Sparrow- the eyelashes have an opacity map that thins out the eyelash mesh...
BUT, the shadow is thick and that of the entire mesh, while the lash itself looks thin.
And you see what looks like a makeup shadowing on her eyes.
But this is not makeup!!!
it is a shadow of the full-solid eyelash mesh


And this happens with everything that uses Surface-Translucent.
In Sparrow's case, you can even see the default eye-lens translucency materials are destroyed by a shadow somehow onto itself.

One thought is to set shadows as masked as opposed to translucent, but the shadows stay the same while raytracing
The other thought is to use raster translucency, but in 4.23.Previews it does not work while raytracing.

In 4.22.3 it does work, but **still** has the full thick shadows of the mesh while in Raytrace mode.
(Pic 2 - Sparrow 4.22.3 Trans>Raster)
Although, in the case of 4.22.3 Translucency>Raster is far better than 4.22.3 Translucency>Raytrace, which is a mess!
(Pic 3 - Sparrow 4.22.3 Trans>Raytrace)

And see, this is why we HAVE to press on Raytracing...because it is very problematic in 4.22.3, so we want to see it done right, without regressions, in 4.23!!!
Also, this happens with ALL characters (ie Daz), not just Paragon's.
TO show Paragon in 4.23 I copied new untouched Paragon asset from 4.22.3 to 4.23 Preview.

People will say it's a shader issue (in vague non-specific terms).
So, specifically, it relates to a Raytrace Issue with incorrectly shadowing Opacity on Translucent Blend Mode.


THX

[VictorLerp]

Hi Amanda.Bott - could you please pass on the info that in Sequencer the Attach / Detach function has been broken since at least 2017? This feels like it should be a very basic function and I have no idea what it hasn't gotten any more attention.

I'm looking into the sequencer issue, no estimated time for a fix just yet but it's on my radar now!

[Daffrendo]

Just a touch more on the Translucent Blend Mode shadows. Here is a more flagrant example of what happens.
This Daz avatar has a lash mesh that amounts to a solid bar, and is masked with an opacity texture to 'alpha'-in the lashes.
So in Unreal Raytrace, this opacity texture does that just fine, it creates the lashes.
But...when it comes to the shadow, the Raytrace lighting only knows to shadow the whole entire mesh. Thus, you get bars behind the lashes, which is the actual full solid mesh's shadow.

Again, this is not a "texture thing", because in Raster, it works perfect. Raytrace just does not know yet how to shadow only the visible part of the Translucent texture.

*Note* - I am seeing online this phenomenon also in cases of other render engine's earlier development, such as Octane Render, Indigo Render, and NVidia Iray render engine.
Apparently it is not really too uncommon of a thing to happen in a render engine's development.
Welcome to the big leagues, Unreal!! You're almost all grown up, now!...

[Tim Hobson]

Ok, on RAYTRACING-
You get a full-mesh raytraced shadow for translucent opacity-mapped meshes. So, the texture looks mapped, but the shadow is of the full mesh.

This is already noted in the Ray Tracing page's limitations. Translucent shadow support is not yet implemented (for 4.22 or 4.23), so the shadow will show as opaque. Ray Tracing with translucency is a very difficult problem to solve and it's on the list of things to tackle, just not this release.

[Nocturness]

hi guys just testing ssgi and hdribackdrop with rtx2080ti. Compared to 4.22.3, there is an improvement in denoiser but there is really a problem with rtgi.

[Daffrendo]

This is already noted in the Ray Tracing page's limitations. Translucent shadow support is not yet implemented (for 4.22 or 4.23), so the shadow will show as opaque. Ray Tracing with translucency is a very difficult problem to solve and it's on the list of things to tackle, just not this release.

Thanks. If it really just is not on the to-do list until later, okay, this is good to know.
But! We are already saw fundamental regressions from 4.22.3, so we have to keep pushing for progressive Raytracing development and Translucent Material's rights.

THX again Tim!

[DamirH]

How to use this ?

Remote Control over HTTP

Also interested in this one. More importantly perhaps - what are the intended use-cases for this? What was the reason for its implementation?

[ExtraLifeMatt]

Also interested in this one. More importantly perhaps - what are the intended use-cases for this? What was the reason for its implementation?

You could use it for a variety of things. Running unit tests / automated smoke tests, baking assets that require the editor to be running, remotely setting CVars at runtime, etc.

[Sephiroth_FF]

Thank you for 4.23 Preview! About Chaos Physics, I know the version of PhysX used in UE4 was a CPU only implementation because the GPU accelerated version was using CUDA and could only run in NVIDIA hardware but what about Chaos? Since it's developed by the Epic themselves, could it make use of DirectCompute and VulkanCompute for acceleration and could that computation be offloaded to a non-rendering GPU, similarly to Dedicated PhysX GPU, but in a vendor agnostic way? My guess is it's probably CPU only since NVCloth has a vendor agnostic DX11 Compute implementation but UE4 uses the CPU only implementation there too.

[remozseo]

How to import HDRI maps when using 4.23 I am getting the error message:

[SM5] (Node TextureSample) Texture Sample> UVW input required for cubemap sample

Help: I don't get it - what do I have to do within the material editor to make a simple .hdr file work?

[remozseo]

I would like to exchange the HDRIBackdrop Geo to a regular sphere. I am able to add a sphere and scale it as I want to.
But how the heck do you assign the ImageBasedEnvironment Material?




https://www.mediafire.com/view/imcut...k/material.JPG

[Daffrendo]

Just want to reiterate about Translucent Materials when RAYTRACING in 4.23 Previews 1-2-3.

There are 2 issues:

1) Translucent Material meshes render with full opaque shadows, and this is a known issue.


2) When in Raytrace mode, Translucency as Raster is non-functional, even if selected.
(in contrast, this does work in 4.22.3)


Thanks to Leo Rakes and Nocturness for moving Raytracing findings forward.