This is what I have meant. Is it possible to achieve this effect with substrate? Before it was opaque/subsurface and by adjusting opacity you control how much light will go through
Bloom on SingleLayerWater (from emission, or bright specular like on water) disappears when there is any Translucent in view that has refraction set to anything but NONE.
This happens regardless of which blend mode the translucent material has (in the video it is set to TranslucentColoredTransmittance). And regardless of what refraction method. Deleting the translucent object, or moving it out of view makes the bloom return on the SLW material.
Noticed this in my project on my ocean specular getting less bloomy when I had a waterfall (translucent with refraction) in view. Pops and flickers and looks dumb. This a bug, or an overlooked edge case?
Tested in Launcher version 5.4.4. Downloading 5.5.4 now to test. Edit: Also happens in 5.5.4.
Tested in the Third person sample scene. All materials have their default settings. Default Post Process values too. Can give more info if required
This issue does not happen when not using Substrate.
@Rudheim Yes that should work as transmittance for Subsurface and SubsurfaceProfile shading models. Especially if using the shading model node: it is the same parameterization as before. We have conversion and setup working for that. It has been revisited in 5.6, the subsurface technique can be selected on slab now).
@DMDevil Thanks for the detailed report! I have added a task for us to check what is going on.
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are planar reflections broken with substrate?
there seems to be some weird culling issue with it where i can only see a few large pixels around the center of a planar reflection on a flat massive plane
Is Substrate volumetric coming? I want to fade out vdb but blend mode is restricted to additive. UE 5.5.4
It`s not about exact issue, but current limitations of Substrate systems. The documentation says
Unifying Substrate and Material Layers is a strong area of interest for future development
So if U can please tell about last updates about this feature or maybe the terms of integration already defined?
I wonder how to create a system near to legacy MaterialLeyerBlend.
As far as I know there is nothing specific to Substrate in planar reflection. Could you try on the legacy/non-substrate mode if the issue is happening there? Otherwise do you have a picture/repro case for it? Thank you!
There is currently some work happening on this at the moment, but it is still under heavy development. There is currently no exact ETA when this will land. We will communicate about it when ready.
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Hello @imtrobin2 ,
I am not exactly sure what you mean by that. Subsurface, SSSPRofile, Volumetric materials for fog and clouds are supported in Substrate with the same feature set.
Volumetric materials requires additive blending because that is how participating media parameters needs to be accounted for internally (scattering and absorption coefficients, emissive). You can still blend anything from the material or add two medium contributors using appropriate weight to have them fade/bland in and out.
There are plans for more volumetric features/improvements in the future but not short terms. If there are some ideas you want to share you can make a small note here about that.
I am trying to build a simple Glass Shader with Substrate.
A black and white texture map, which should control Transparency and Solid.
I can’t figure out how to construct that simple node when using Substrate and the Substrate Transmittance to MeanFrePath node.
Thanks a bunch for any ideas and hints.
appreciate it!
Hello,
Details for translucency, transmittance and alpha as coverage are in the documentation in this section Overview of Substrate Materials in Unreal Engine | Unreal Engine 5.5 Documentation | Epic Developer Community .
I have lost track of the development of progress, are colored shadows with substrate expected to be supported in 5.6, or is that expected later down the line? I had a more in-depth question but wanted to check in on that first.
Hello,
Colored shadow is not in 5.6. It is something we want just like you 
but not at the top of the priority list right now. Tracing translucent colored shadow is easy in general but it will expensive. So special techniques and optimization will have to be developed.
As a reminder for everyone, colored shadow in unreal is only supported via the lightmap baker and the path tracer: Using Colored Translucent Shadows in Unreal Engine | Unreal Engine 5.0 Documentation | Epic Developer Community. RT translucency only support opaque shadow from translucent IIRC.
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Fair enough, makes sense. I’ve been making use of colored shadows via GPULightmass for a while now and I love the results (bounce lighting from stained glass is the desired effect) but even with a 40 series GPU the bake times are considerable. Thank you for informing me.
Groom / Hair shader doesnt seem to support opacity mask, is that something that might get supported in the future?
I have verified that it is not supported in Substrate and Standard, but im not sure where else to ask about this.
Thanks
Hi, @SebHillaire
You mentioned: “Performance for Substrate Materials scales according to complexity and desired budget of a project, with legacy materials having a similar cost as before.”
Could you elaborate on what you mean by this?
Thanks for clarifying!
Hi,
it means that:
- if you use a single slab with input that in the end corresponds to one of the existing Shading Model, then it is expected to have similar performance to the non substrate path. You can see what shading model it maps to when using the pixel debug tool.
- If you use new or more complex features (sss, cloth, dual spec. specular lut, glint, F90, etc.) on a slab then cost will increase accordingly.
- Then if you have N slab output by a material, you will pay N times the cost of lighting (Direct and GI) as of today. And you will pay for more GBuffer memory to store more slabs. To mitigate that later we want to experiment with stochastic lighting but this is WIP and not short term.
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Hi, indeed in both Substrate & Standard mode, hair strands doesn’t support opacity mask. There is no short term plan to support this at this point.
/Charles.
Hello! I was looking over the 5.6 release notes and I wanted to ask:
I noticed that this feature is now supported, but checking both the substrate and lumen documentation I couldn’t find any guide to enabling and using it. Would it be possible to update the documentation to include this, and in the short term would you have any advice for doing so? Thank you very much.
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Hi,
I believe this happening when using lumen, hardware ray tracing and hit lighting for reflection / refraction with refraction > 1.
Also, ray tracing for translucent can be enabled using r.RayTracedTranslucency.Allowed.
Just be aware that this is not cheap.
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