Corrupt Math Expression Node

Development Programming & Scripting
1

I had some behavior with an unstable blueprint and tracked down offending node. Reporting it here in case it’s helpful for tracking purposes.

Win 7 64, UE 4.6.1, 4.7.3

Symptoms

  1. Blueprint commonly would corrupt upon saving / exiting editor. project could no longer be opened until offending BP was rolled back.

  2. Refreshing nodes in BP would crash editor

Cause:

I tracked it down to a math expression node in one of functions. Refreshing this node led to an instant crash.

Replacing/removing this node caused instability to cease.

Conclusion:

Unsure of what underlying factor may have contributed to node becoming corrupt so I can’t give you definitive repro however, it happened only after node was disconnected but left in graph. I Can provide file to you if you like, though there are a few external dependencies you’ll have to work around.

2

Hey ,

I haven’t been able to reproduce this in 4.7.3 so far. It’s probably a one-off occurrence, and I’m glad you were able to find problem, but unless we can find what caused corruption I don’t think there’s anything we can do. Just in case it has something to do with input, can you give me expression you used in node? Thanks!

3

Yeah, I figured it is probably just one of those random things. Here’s expression though, just in case: sqrt(100^2 + 100^2)

4

Okay, yea, I tried with that and still couldn’t reproduce. I’ll go ahead and resolve this for now, but please let us know if you find that this is consistently reproducible. Thanks!

5

No problem, thanks for looking into it!