Are nodes vanishing inside Material Functions for anybody else?

Vexurayr · February 6, 2025, 5:54am

Hey yall. I thought I should pose this question here because I can’t gather enough information to replicate what looks like an engine bug. I made a Material Function to significantly shrink down the amount of nodes I need in my landscape material. It handles randomizing texture inputs so the landscape won’t have such obvious repeating materials, and thanks to it I got my landscape in a state I’m really happy with.

Material Function Inside my Landscape Material

This is when the “bug” steps in.

Material Function Missing Nodes

I’ve noticed twice now that a bunch of nodes inside the Material Function disappear all on their own. All I had to do was close the window, and later when I opened the function up again, nodes were gone. The first time, I just stitched back the bit of work I lost. The second time, way more nodes went missing. There’s absolutely nothing in their place to click on. When I click the Stats page, there’s a bunch of errors because of course a bunch of connections are lost. I really don’t want to keep redoing this work.

Material Function Errors

I don’t see any consistency in the nodes that are vanishing either. I have Named Reroute Declaration nodes vanish, math nodes like Multiply vanish, Texture Sample nodes vanish, and Landscape Layer Blend nodes vanish. Just to check, I reloaded the project, and all the nodes are still missing. I’m working in UE 5.5.2.

Frenetic · February 6, 2025, 6:05am

Totally happened to me in since I was able to test in 5.5.2.

I thought I was literally going crazy, I mean it. I tried 3x and kept having the function revert back to the wiring it was before i edited it. Yet some named-references would still be in the graph.

huyenhuy212526 · February 20, 2025, 4:33am

I think it is an engine bug. I use UE 5.5.3
When i try to create water shader follow this tutorial: https://www.youtube.com/watch?v=HBwJJqZ0nLI

Then these problem happen:

Wave material functions (26:23) nodes disapear after close and reopend engine
when i drag Wave material functions into BlendOffset MF (54:16), the input and outputnode not shown.

Can anybody else confirm that and report it

siftycat · April 1, 2025, 4:53am

Yes, on 5.5.4

I just spent all afternoon building a material function, reopened the project and I’m staring a this:

Edit: After rebuilding from memory because now I know what I needed, I would probably suggest that if dealing with material functions, copy it to a safe location just to make sure. Nothing else appears to be affected but I filed a bug report anyway. Regardless of whether it’s replicable directly, there’s obviously an issue that needs at least filing.

Frenetic · April 2, 2025, 6:08pm

I wanna ask if we were attempting to use named-reroute nodes in a child function? Can we repro this?

Deciphersoul · April 9, 2025, 4:53am

Hello, Has anyone made any progress on this? I seem to be getting the same issue as others have mentioned. Currently before I close any material I save it in a text file to have a backup and close/open the file to verify the info. I have been trying to reproduce this issue but have not found anything consistent. I am on version 5.5.4.