Anyone ever get Sparse Class Data working?


I’m trying to use Sparse Class Data on 4.26 but it is giving some really weird behavior that results in the engine crashing in some pretty core classes.

My setup is simple, I have a struct with a float and a FText. This is my Sparse Class struct.

In the editor, if I modify the FText on a derived child class, the editor crashes in FWindowsPlatformAtomics::InterlockedDecrement (WindowsPlatformAtomics.h line 65). Ok, kinda an obscure error. Going up the callstack there seems to be some calls looking for buffers and memory.

Even weirder: for the float, if I enter in any value it immediately resets it back to zero. If I try to enter in a value a second time, the editor crashes in UObjectBaseUtility::GetPackage (UObjectBaseUtility.cpp line 182). Apparently “Top” is NULL when it shouldn’t be.

The only thing that I can think of is that my struct has inheritance, but I don’t understand why that would be a problem, the compiler seems fine with it. And I’m not sure how this all relates to the package, other than Unreal maybe can’t find the package to save the sparse data to.

Maybe this is just an Unreal bug? Curious to see if anyone else has had similar issues.


Still happening on 4.26.1, albeit in a different spot now.

Beginning to think that the Sparse Class Data system just flat out doesn’t work at all…