In SubsurfaceBurleyNormalized.ush, in GenerateSampleInfo(), you used disk sampling right? But why is the PDF of it is R(r) * r * 2 * pi which I think is for sampling radius only? Shouldn’t it be R(r) * r, which is for sampling radius and angle(disk)? And in Unity they used R(r) * r. I’m confused sorry but correct me if I’m wrong.
The Slab node allows you to get (colored) transmitted light, though the control of MFP and thickness. If you want to control the pass-through (aka the old opacity input), you probably need a coverage node at the end of your slab, to control how much this slab covers. Maybe this is already something you already had?
/Charles.
Good question. This is orthogonal to Substrate and I’m not sure the reason behind that. I will ask around.
/Charles.
Charles, thank you for the reply. I still haven`t tried the Coverage node in that case. Gonna do it right now.
This does not ring a bell, and seems related to shadow cache/update rather than Substrate?
Interesting thing. The PT and Lumen show different behaviour when using Directional light. The PT kinda ignores it. Is it as supposed to be? First one is PT and thse second Lumen
One more fact. When unchecking CastRaytraycedShadows this strange thing happens. One Directional light, but seems like it is two.
using an hdri skylight with a “hot spot”? this may cast it’s own shadow into the lumen scene volume data.
Yeah I`m using HDRI Skylight. As you said it was the case. But why this shadow from windows visible only in path tracer mode?
Thank you for the help! I’m looking forward to hearing you back!
i figured it out, the main issue is that the stationary light shadows seems to break down on objects that have a large bounding box
I came across a really basic render issue with substrate this morning, but can find no reference online to anything similar. It’s SO basic that I was sure this meant I made a stupid error somewhere - but I’ve re-created it in a fresh download of the ‘Electric Dreams’ project in 5.5, so it seems to be legit.
The issue:
Layered substrate slabs exhibit a black edge / halo at the layer boundary when lit only by a skylight.
Close up - it’s only 1 pixel wide whatever the distance from camera:
Even closer:
To replicate this:
- Create the simplest possible layered slab material - if it uses a ‘vertical’ layer blend, the black line appears on the outer edge of the boundary, if it’s a ‘horizontal’ blend, it’s on the inner edge, but still visible
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Create a new default level
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Turn the skylight to ‘specified cubemap’, and select the default epic courtyard HDRI
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Turn the directional light off
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Add a mesh to the default level, and assign the material. In this test case, I used the ‘Electric Dreams’ project - the mesh is ‘Rock_Formation_04’ and the mask texture is ‘T_NoiseMask_RGB’, but any mask or mesh shows the same thing.
Is there a magic CVAR I’m missing?
Is it possible to create dark decals with the Unlit BSDF? Regardless of what blend mode is used, the decal appears not to use the transmittance color input.
The Substrate docs say:
Substrate Decals currently use the same features as the legacy Decals blend mode path.
Does this mean that the new transmittance paradigm isn’t supported, and requires a slab BSDF to specify a “base color” instead?
Hi,
Transmittance color is indeed not part of the decal definition in UE. Only grey scale throughput (summarized from coverage and transmittance).
When it comes to unlit: I do not think it is supported no. I’ll add a task to clarify that situation.
Thanks
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Hi,
Thanks for reporting that problem. We are aware and an improvement should be in for that issue in 5.6.
any updates on this? or is it not substrate related
As already mentioned, this likely not related to Substrate so should not be discussed in that Forum thread (Unless you prove it is due to Substrate, Post edit: lots of things to do right now so we cannot look at everything anytime, there is a priority queue) or should probably have its own thread.
Still, I have reported that behavior to devs in charge of shadows.
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With legacy material by placing light source behind the object you make it glow. Is it possible achieve the same subsurface effect like in Legacy Material. I am currently testing Substrate and the only thing I can achieve is to make corners more blurry and shadows less contrasty, wax like look. But nothing works to make light go through
Hello,
We have transmission shadow (if that is what you meant) working with Wrap and SSSProfiles for different shadow types (SM, VSM). Hard to guess more from what you describe what might be broken.
for some odd reason, glass materials in substrate doesnt seem to work with static lights (as in they dont have transparent shadows)
is that a bug with substrate or something else?