Nanite Tesselation + Mesh Distance Fields works 5 seconds then breaks.

Lyawx
Fri, 03 Oct 2025 15:25:23 +0000
Rendering

Need help on a weird bug

I am currently using Unreal 5.6.1.

For beginners : SDF means Signed Distance Function : a function used to check the distance from a point to the closest point on a specific surface.

Hello there. I’m trying to create a simple water shader using Nanite tesselation displacement, and SDF functions to create ripples close to shores or any other partly submerged objects.

I sadly encounter a weird issue where my Distance Field Mesh replacement works for like 5 seconds and then the SDF breaks (AKA basic UE behaviour with a mesh tesselated and no SDF mesh replacement).

Does anyone know why ? I saw a post about it posted in AUG (2025) but it seems like it lacks details or screenshots or really anything to help beginners and normies to understand anything so I thouhgt I’d just create a new one.

Lastly, I’m using the same mesh with Nanite disabled for the SDF replacement mesh? Is it a problem ?

Any ideas ? ^^

Weird SDF mesh replacement + Nanite bug.

Description of the video

I firstly try to recreate the working features by changing the Lumen Mesh Card Numbers which triggers the (re)generation of some mesh Data. It then works properly for 5 seconds (mesh is being displaced only where it is close to the cube) then everything break again.

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