Simul Support ExchangeCategory: CloudsCurrently known issues and notable fixes from 19th February Update
Chris_Simul Staff asked 1 year ago

Hi all,

I thought this might be a good place to acknowledge the issues we are now aware of in the current build.

February 19th Update

This update was bringing 4.3 and 4.2a to Unreal 4.26, Unity will have a following release shortly with everything within this update.

Notable fixes –

Compatibility and build for the 4.26.1 Unreal Engine.

“Enabled” tick box within the cloud layer now functions, allowing you to disable and enable layers for ease of control.

Some blueprint naming convention clean up

Some performance optimization and general smaller bug clean ups.


Known Issues:

Cloud Volumes Control UI is currently broken

Rain Streaks non functional with the new Variable Grid (this has knockon effect of rainbows being unable to generate)

4.1a Cloud scheme appearing as a solid cloud layer


December 4.3 Release information can be found here:


July 21st Update –

Notable fixes –

Buoyancy fixes for 4.2a – objects will no longer float upwards.

Packaged builds should no longer appear slightly different when compared to the in-editor view.

Water settings are now alterable at runtime – This can be done manually via the sliders if in editor. Or via blueprints / cinematic sequences within unreal.

A vast variety of smaller fixes and ironing out of bugs


Known issues (and workarounds) –

Unreal 4.25.2 is unable to package due to an error. We are looking into what has caused this and will supply a fix as soon as possible.

The above issue has been fixed by the Unreal 4.25.3 build and no longer requires a workaround.

4.1a – Crash upon adding a newly created sequence directly into the sequence actor – Can be avoided by first opening the newly created sequence, then adding it to the sequence actor.

4.2a – Crash when naming a moon, deleting it and naming another moon the same as the initial moon – Can be avoided by naming the second moon an alternate name.

Niagara plugin becoming a built in feature within unreal engine may cause some conflicts when packaging alongside trueSKY, most notably causing the sky to appear black. If niagara is not in use in the project you can disable it as an active plugin to avoid this, if you are using Niagara and require packaging the Simul Unreal Binaries are available and will resolve the issue.

We are aware of some issues when using full-screen on larger monitor sizes (4k) – some fixes have been rolled into the build which should alleviate some of these. But some may remain.

Precipitation may appear to not be working, and the translucent RT texture is showing up blank – This was just a faulty default within this build – Within the precipitation settings in the sequence actor and changing the rain near threshold from its default of 30, down to its minimum will fix this.

Star Background texture appearing low res / low quality on first boot / within packaged build / within standalone play. This is an unreal side issue we are working to fix, for now however locating the texture within the plugin content, and changing the mip gen settings to use “nomipmaps” will fix this.

Rendering sequences within Unreal using their “Movie Render Queue” causes the rendered sky to appear black – We are looking into fixes for this – Currently you can work around by using regular Render Sequences, and if needing to do large amounts of renders at once use a batch script.

Generating wakes with water probes and a consistent force does not appear to work – Potential workaround for this issue can be found here – Delaying your force slightly causes the water to behave more as expected.

I will update this list as more issues become apparent (I have inevitably missed some).


Updated by Chris


May 20th Update – 

I thought this might be a good place to acknowledge the issues we are now aware of in the current build.

4.2a Update

Unable to open sequencer due to missing VCRUNTIME140_1.dll. (Possible fix for now – Install Microsoft Redistributable from )

Uncommon DX12 + RayTracing Crash on Opening Scene

Rare Crash when moving Keyframes in Cloud Window

Cloud lighting can sometimes appear slow and obvious

Warning about “MaxAtmosphericDistance”. However, this is only a warning and should not cause any issues.

Resurfaced bug related to water not appearing in Standalone Play

A cloud layer is needed to use a newly created Sequence

Performance issues on certain Graphics cards

This is related to UE4. We are aware of other issues in Unity, but are still busy resolving these before we talk about them further.
Some of these have already been fixed for the next push, but others are still ongoing. If you have any information you think may be helpful in regards to fixing any of these issues, please let us know in the comments below!

ClaudioPiccinni replied 11 months ago

4.25.3 does crash on packaging because of TrueSky:

UATHelper: Packaging (Windows (64-bit)): LogWindows: Error: begin: stack for UAT
UATHelper: Packaging (Windows (64-bit)): LogWindows: Error: === Critical error: ===
UATHelper: Packaging (Windows (64-bit)): LogWindows: Error:
UATHelper: Packaging (Windows (64-bit)): LogWindows: Error: Assertion failed: (Index >= 0) & (Index < ArrayNum) [File:D:\Jarvis\UPlugin\version\4.25\Engine\Source\Runtime\Core\Public\Containers/Array.h] [Line: 674]
UATHelper: Packaging (Windows (64-bit)): LogWindows: Error: Array index out of bounds: 3 from an array of size 0

1 Answers
Justin Darlington answered 1 year ago

ISSUE: Uncommon DX12 + RayTracing Crash on Opening Scene
I was able to get around this issue by modifying the UE4 source code:

James Evans Staff replied 1 year ago

Thanks for this, we’ll take a look