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.
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.
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.
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.
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.
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.
Happening to me too. It definitely has to do with Named Reroute nodes, as those are the connections that keep disappearing. It wasn’t happening for a little while in the material function I experienced it in, but suddenly became unusable. So it’s possible there’s a bug that only occurs once you’ve declared x number of Named Reroutes. My function has (had, I deleted them all and reverted to spaghetti because at least it’s reliable) around a dozen Named Reroutes.
My issue is occurring in a UMaterialFunction. I haven’t noticed it in a UMaterial yet, but I haven’t built one with as many named reroutes as my function yet.
That’s actually a pretty smart workaround. I am however making a code plugin which will eventually be on the marketplace, so I basically have to force myself to not use any Named Reroutes now, as I can’t afford to risk the plugin’s materials breaking for people who paid money for the plugin.
I’m actually pretty frustrated about this, because I thought Named Reroutes were production-ready. They were introduced for the material editor back in the UE 4.27-5.0 days, so what gives?
Same, I was in a material function inside my main material, IIRC and then the child stopped working when I saved and closed out the project. When I drilled down the child was corrupt per the above, but I’ve not tried to test this, just what I recal..
I’ve had this bug for a bit. I’m on 5.2 still. I’ll have a material that is totally fine for a bit. Then I’ll go into the graph and change a parameter and save again, and suddenly there will be a compile error because something isn’t hooked up and there’s a random Lerp missing or something.
I keep running into this any time I copy and paste a node into a material function (especially if the nodes are from a different material). It pastes fine, I wire it up fine, and then when I save and re-open the node, the pasted nodes are missing. I am not using any named reroutes.
You’re not alone — disappearing or vanishing nodes inside Material Functions in Unreal Engine (UE) is something that’s occasionally reported, and it can stem from a few different causes.
