Path tracing not rendering transparent materials

Unity Engine
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1

Hi all,

I was wondering if there was a fix to Unity not being able to see through transparent materials using the Path Tracer. I have tried using HDRP 7.0.1 through to 7.1.6 with Unity 2019.3.0f1 through to the latest alpha build, 2020.1.0a14.

Any help would be greatly appreciated

1 Like
2

Hello,

I have the same problem with Unity v.2022.2.3f1 (HDRP v.14.0.5)
Is this a bug or a Path Tracing limitation?

Thanks!

3

I believe what you are experiencing is the fallback when your objects are single sided.
Basically, pathtracer fallbacks to “thin” model (no ray refraction / intersection) if the object is single sided.
Cf documentation.

I just checked in 2022.2 and it works correctly.

8759260--1187311--upload_2023-1-26_18-48-7.jpg
8759260--1187311--upload_2023-1-26_18-48-7.jpg1474Ă—728 644 KB

If it’s not the case, please report a bug.

4

Hi,

I’ve seen the problem is related to asset bundles.

When I assign the material directly in the editor it works properly, but if I assign the material via asset bundle during execution then there is no transparency. Maybe I’m doing something wrong when I create the asset bundles with the materials inside.

Maybe I have to include a shader in the Always Included Shaders?

Any idea?

5

Okay I see, it might make sense if you built the asset bundle a on project where raytracing wasn’t supported.
Technically, when building a bundle, HDRP include the shader pass it needs, so if there’s no raytracing support, it won’t include the pass.
Then, when you import your asset in a project to render with raytracing, the shader still don’t have the pathtracer pass, so it does not render correctly. More details here .