Separate Translucency in Underwater Post Process Material

Skyrow
Sat, 30 Mar 2024 16:23:42 +0000
Rendering

(UE 5.3)

I’m making a post process material for the Water System but when the camera goes under water at a certain point, it looks like the Separate Translucency render target get disabled as you can see on the pictures below.

On the left : camera is above the point, right : below the point.

So It’s not when entering the PP volume, and I’ve tested with the water surface disabled and the same happens. I’ve checked the settings of the WaterBody and WaterZone, but nothing seems related (or I missed it).

It’s not bad at all, because I don’t want to have the reflection capture on my translucent materials if they’re underwater, but I wanted to sample the Separate Translucency Alpha in my underwater PP material just to make a mask and prevent them from being fade out by the far fog that is sampled on the scene depth / custom depth.

Another bad thing is, as you can see on the first (top-left) picture, the reflection capture is still visible on the glass, so it vanishes in one frame when going lower. So I may consider disabling Separate translucency in the whole project, in that case, how could I still have a way to sample the translucency ?
Edit : It is actually not only the separate translucency that vanishes, but more likely the whole translucency that is no more deffered (Or I don’t get what’s happening).

I’ve to mention that I cannot use custom depth writes of the translucency, because the results are not good, and I don’t use clip plane position to determine where the pixels are underwater, but I sample the scene depth and custom depth on a huge invisible box at the ocean’s bounds to make this computation, so it would mess with it.

I’m really not a render pipeline expert, so any help for comprehension would also be appreciated, also if there’s another solution to achieve what I’m trying to do, I would love some hints.

6 posts - 3 participants