Desktop crash in spline editing

Development Programming & Scripting C++
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1

Hello,

4.14 and 4.14.1 started to desktop crash when doing the following:

  1. activate landscape
  2. Edit splines
  3. mark spline segment
  4. Add spline mesh into array
  5. Change either Scale to width or change forward axes or add spline and add new point

I traced the crash to this code:

Engine\Source\Runtime\Core\Private\Math\TransformVectorized.cpp
line 186

FTransform FTransform::GetRelativeTransform(const FTransform& Other) const
    {
    ...
    **if (Other.IsRotationNormalized() == false)** // this is crashing
    }

where obviously reference is invalid.

It’s called from LandscapeSplines.cpp (line 2311)

const FTransform RelativeTransform = OuterSplines>ComponentToWorld.GetRelativeTransform(MeshComponentOuterSplines->ComponentToWorld);

Thanks,

Jan

2

I traced the issue down to the following:

LandscapeSplines.cpp line 2308:

		auto* const MeshComponentOuterSplines = MeshComponent->GetAttachParent();

returns NULL, however there is no safeguard with:

const FTransform RelativeTransform = OuterSplines->ComponentToWorld.GetRelativeTransform(MeshComponentOuterSplines->ComponentToWorld);

so that’s the cause of the desktop crash. I have no idea, though, why GetAttachParent() should return NULL when I simply clicked on existing spline at the checkbox Scale to Width.

3

Hi metamorphium,

I attempted to reproduce this but I couldn’t get your results. I’m going to need some more info:

  • What exactly do you mean by ‘Add spline mesh into array’?

  • Could you provide the crash Callstack and your Epic ID/Machine ID? This is so I can track the crash.

  • To help clarify your repro steps, a video of you reproducing it in a blank project would be very helpful.

4

Hi TJ Ballard,

MachineId:1855E1F54D480A8ECB38CC97CA9BAF52
EpicAccountId:a7afbb1c017b466abcff3112d1eec6c5

I’ve recorded a short video which is on YouTube. As soon as I click at the checkbox for the second time, it once again desktop crashes. Also note, that I tested this on three different PCs and with both 4.11.0 and 4.11.1, the crash is 100% replicable.

Crash minidump

5

So just to clarify, the original crash and the callstack are from 4.14, but you were only able to reproduce it consistently in 4.11?

6

Sorry, a typo in my previous post.
4.14.0 and 4.14.1. I must have been tired typing that. :slight_smile:

7

I attempted to reproduce the issue from your video but I still wasn’t able to get the crash. Is it perhaps linked to the test asset you are using or the project? Could you try replicating the crash in a small test project and upload that here?

8

We haven’t heard back from you in a few days, so we are marking this post as resolved for tracking purposes. If you’re still experiencing this issue, please feel free to post back here with additional information to reopen the post.

Cheers,

TJ