Hint: copy BP graph from UE5 back to UE4

Development Programming & Scripting Blueprint
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1

had to downgrade a few BPs,
but when copying a graph from UE5 to UE4, all links get missing.

workaround:

  • copy the source BP
  • paste it into a text editor (yes, really)
  • remove all occurences of “PinType.bSerializeAsSinglePrecisionFloat=False,”
  • copy all the text again
  • paste it into the UE4 BP

removing normally can be done by text editor’s find/replace command, replacing with -nothing-

some obstacles still apply, like float/double incompatibility of some functions, but it makes work a bit easier.
some can be soplved by using RB+‘Refresh Nodes’

2

Thanks for sharing, I am looking for the same thing, but get an error:

Assertion failed: Pin [File:D:/Build/++UE4/Sync/Engine/Source/Editor/BlueprintGraph/Private/EdGraphSchema_K2.cpp] [Line: 6405]

In both copying direct from UE 5 BP as with your method.

I am willing to downgrade from UE 5.2.1 to UE 4.23

Is it possible to fix this?
Thanks in advance!

3

just tried it again, from UE 5.2 to UE 4.26, and it worked.
I just had to create the missing variables via RM-“create variable” and replace all “real” pins with “float” pins, and then was able to compile it.
That EdGraphSchema_K2 has somtehing to do with the connection between two pins, but I don’t know any further details.
You may send me the copied text related to your graph that you are copying, and I may give it a try with 4.26.

Also you may try to locate a not too-big part which causes the issue, and recreate it in UE4, then copy both version and compare them to see what’s different. That how I found out the initial solution.