Translucent material issue

[john212]

Hi all,

Having some issues with a material I’ve made in UE5 NvRTX, it’s meant to be a translucent water material that I have applied to a geometry cache. (FYI I need a non 0 value in the opacity for the motion blur to render).

I’m using Lumen with all the hardware ray tracing options turned on, except Translucency is still set to raster as with the current UE5.0 build there doesn’t appear to be a way to get correct ray traced refraction like in 4.27.

With that in mind I’ve got a result I’m happy enough with, the issue though is as soon as I run or simulate the game the material changes, it becomes brighter and more saturated, not good! The same issue does not happen in vanilla UE5.

Here is what the material looks like in the editor before running/simulating (top) and once the game is running (bottom) + the simple material parameters (side):

Can anyone help with this issue?
Thanks,
John

[john212]

Feel free to ignore most of the above!

What has happened is, my lighting sub level was getting loaded twice and that’s what was causing the difference! Interesting that this only became apparent when using NvRTX, however in any normal scenario you wouldn’t have 2 suns and 2 skylights ;)

[MarkusHoHo]

Hi john212,

Thank you for sharing how you fixed your issue!

A bit of clarification on the topic though. Lumen is a UE5 specific implementation of ray tracing shaders by Epic, not NVIDIA. IOf course it will use the NVIDIA GPU if Hardware Ray Tracing is enabled.

The NVIDIA specific Ray Tracing APIs are DLSS, RTXGI and RTXDI. I highly recommend watching our Webinar on the topic.

Nice textures by the way!