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Unreal Engine 4.26-Chaos Preview now available on the Epic Games launcher

I don’t plan on using Chaos anymore for my game projects until it is 100% production ready. PhysX is limited but although with some flaws it should still be usable. However indeed Chaos is needed but it’s just useless if it is not absolutely stable and reliable with no major issues. We will see if Chaos can be used for real with the 5.0 release as it should be the case or once again there will be bugs like with other APIs in the engine causing people to wait for the next release endlessly. I really hope that Epic Games managed to make UE 5.0 source code fully modular and that all reported bugs would get fixed in a given release and not wait years to get fixed as it keeps happening with UE4.

I have some strange objects behavior.
When I use my own ChaosSolver in a level and attach it to a GeometryCollection, the GeometryCollection not response by any channel or type for LineTrace. If I dettach the ChaosSover from GC, the GC will response normaly.
Is it okey for Chaos? Is ChaosSolver isolating the GeometryCollection for any collision?

I’m guessing a bug in the chaos vehicle…
If I start the game without an already placed vehicle in level it just hovers in the air. It’s spawned properly and all but looks like doesn’t have any physics. It responds to input (gears set to 1 or R). If I start the game with a vehicle in level and option auto possess is set to pc0 it works fine.

I second that cloth created in physx builds take a very long time to load. Happens both in editor and in test play. It also takes up all of my RAM like 5 times over.
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How can I solve the problem with the fact that a project with chaos caching enabled is not going to be built?

I can confirm that at current state, skeletal rigid body is not stable, and can not be used. That maybe comes from the unstable constraint.

I have a problem with 4.26 Chaos. I just created a new project on this version, enabled Chaos Vehicle, added a wheel blueprint, vehicle blueprint with basic controls and a simple terrain. Chaos vehicle works really good, but when I try to package my project, I get this message:


UATHelper: Packaging (Windows (64-bit)): ********** BUILD COMMAND STARTED **********
UATHelper: Packaging (Windows (64-bit)): Running: F:\Games\Epic\UE_4.26Chaos\Engine\Binaries\DotNET\UnrealBuildTool.exe LinearGame Win64 Shipping -Project="C:\Users\Admin\Documents\Unreal Projects\LinearGame\LinearGame.uproject" "C:\Users\Admin\Documents\Unreal Projects\LinearGame\LinearGame.uproject" -NoUBTMakefiles -remoteini="C:\Users\Admin\Documents\Un
real Projects\LinearGame" -skipdeploy -Manifest="C:\Users\Admin\Documents\Unreal Projects\LinearGame\Intermediate\Build\Manifest.xml" -NoHotReload -log="C:\Users\Admin\AppData\Roaming\Unreal Engine\AutomationTool\Logs\F+Games+Epic+UE_4.26Chaos\UBT-LinearGame-Win64-Shipping.txt"
UATHelper: Packaging (Windows (64-bit)): Writing manifest to C:\Users\Admin\Documents\Unreal Projects\LinearGame\Intermediate\Build\Manifest.xml
UATHelper: Packaging (Windows (64-bit)): Building LinearGame...
UATHelper: Packaging (Windows (64-bit)): Using Visual Studio 2017 14.16.27027 toolchain (C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.16.27023) and Windows 10.0.17763.0 SDK (C:\Program Files (x86)\Windows Kits\10).
UATHelper: Packaging (Windows (64-bit)): [Upgrade]
UATHelper: Packaging (Windows (64-bit)): [Upgrade] Using backward-compatible build settings. The latest version of UE4 sets the following values by default, which may require code changes:
UATHelper: Packaging (Windows (64-bit)): [Upgrade] bLegacyPublicIncludePaths = false => Omits subfolders from public include paths to reduce compiler command line length. (Previously: true).
UATHelper: Packaging (Windows (64-bit)): [Upgrade] ShadowVariableWarningLevel = WarningLevel.Error => Treats shadowed variable warnings as errors. (Previously: WarningLevel.Warning).
UATHelper: Packaging (Windows (64-bit)): [Upgrade] PCHUsage = PCHUsageMode.UseExplicitOrSharedPCHs => Set in build.cs files to enables IWYU-style PCH model. See https://docs.unrealengine.com/en-US/Programming/BuildTools/UnrealBuildTool/IWYU/index.html. (Previously: PCHUsageMode.UseSharedPCHs).
UATHelper: Packaging (Windows (64-bit)): [Upgrade] Suppress this message by setting 'DefaultBuildSettings = BuildSettingsVersion.V2;' in LinearGame.Target.cs, and explicitly overriding settings that differ from the new defaults.
UATHelper: Packaging (Windows (64-bit)): [Upgrade]
UATHelper: Packaging (Windows (64-bit)): Building 2 actions with 4 processes...
UATHelper: Packaging (Windows (64-bit)): [1/2] LinearGame-Win64-Shipping.exe
UATHelper: Packaging (Windows (64-bit)): Trwa tworzenie biblioteki C:\Users\Admin\Documents\Unreal Projects\LinearGame\Binaries\Win64\LinearGame-Win64-Shipping.lib i obiektu C:\Users\Admin\Documents\Unreal Projects\LinearGame\Binaries\Win64\LinearGame-Win64-Shipping.exp
UATHelper: Packaging (Windows (64-bit)): Module.ChaosVehicles.cpp.obj : error LNK2019: nierozpoznany zewn�trzny symbol "private: void __cdecl UChaosWheeledVehicleMovementComponent::FillWheelOutputState(void)" (?FillWheelOutputState@UChaosWheeledVehicleMovementComponent@@AEAAXXZ) przywo�any w funkcji "protected: virtual void __cdecl UChaosWheeledVehicleMo
vementComponent::UpdateSimulation(float)" (?UpdateSimulation@UChaosWheeledVehicleMovementComponent@@MEAAXM@Z)
UATHelper: Packaging (Windows (64-bit)): Module.ChaosVehicles.gen.cpp.obj : error LNK2019: nierozpoznany zewn�trzny symbol "public: static void __cdecl UChaosWheeledVehicleMovementComponent::BreakWheelStatus(struct FWheelStatus const &,bool &,struct FVector &,class UPhysicalMaterial * &,float &,float &,bool &,float &,bool &,float &,struct FVector &)" (?B
reakWheelStatus@UChaosWheeledVehicleMovementComponent@@SAXAEBUFWheelStatus@@AEA_NAEAUFVector@@AEAPEAVUPhysicalMaterial@@AEAM414142@Z) przywo�any w funkcji "public: static void __cdecl UChaosWheeledVehicleMovementComponent::execBreakWheelStatus(class UObject *,struct FFrame &,void * const)" (?execBreakWheelStatus@UChaosWheeledVehicleMovementComponent@@SAXPEAV
UObject@@AEAUFFrame@@QEAX@Z)
UATHelper: Packaging (Windows (64-bit)): Module.ChaosVehicles.gen.cpp.obj : error LNK2019: nierozpoznany zewn�trzny symbol "public: static struct FWheelStatus __cdecl UChaosWheeledVehicleMovementComponent::MakeWheelStatus(bool,struct FVector &,class UPhysicalMaterial *,float,float,bool,float,bool,float,struct FVector &)" (?MakeWheelStatus@UChaosWheeledVe
hicleMovementComponent@@SA?AUFWheelStatus@@_NAEAUFVector@@PEAVUPhysicalMaterial@@MM0M0M1@Z) przywo�any w funkcji "public: static void __cdecl UChaosWheeledVehicleMovementComponent::execMakeWheelStatus(class UObject *,struct FFrame &,void * const)" (?execMakeWheelStatus@UChaosWheeledVehicleMovementComponent@@SAXPEAVUObject@@AEAUFFrame@@QEAX@Z)
UATHelper: Packaging (Windows (64-bit)): C:\Users\Admin\Documents\Unreal Projects\LinearGame\Binaries\Win64\LinearGame-Win64-Shipping.exe : fatal error LNK1120: liczba nierozpoznanych element�w zewn�trznych: 3
UATHelper: Packaging (Windows (64-bit)): Took 13,2756137s to run UnrealBuildTool.exe, ExitCode=6
UATHelper: Packaging (Windows (64-bit)): UnrealBuildTool failed. See log for more details. (C:\Users\Admin\AppData\Roaming\Unreal Engine\AutomationTool\Logs\F+Games+Epic+UE_4.26Chaos\UBT-LinearGame-Win64-Shipping.txt)
UATHelper: Packaging (Windows (64-bit)): AutomationTool exiting with ExitCode=6 (6)
UATHelper: Packaging (Windows (64-bit)): BUILD FAILED
PackagingResults: Error: Unknown Error

UPDATE!

Chaos Preview 2 is now live!

Fixed in Chaos Preview 2
Fixed! UE-106856 Error in Chaos files when Launching onto Android
Fixed! UE-106507 Radius value is not respected in Add Radial Impulse node
Fixed! UE-106288 Character falls throw the floor on TM-ShaderModels when crouch
Fixed! UE-105458 Fixed horizon selection crash in convex mesh cooking
Fixed! UE-104868 Shadow are rendered on a groom asset from no visible objects and are influenced by 3rd person character
Fixed! UE-104854 Gap between adjoining static meshes with physics simulation enabled in Chaos
Fixed! UE-104460 Crash when attempting to add skeletal mesh SK_Mannequin to Sequencer
Fixed! UE-104042 Chaos: Missed Traces at Human Scale
Fixed! UE-103874 Crash when attempting to PIE with some Target option in Add Field Command node
Fixed! UE-103706 Collision issue between floor and cubes in First Person template project



// TODO: Add missing Chaos Cloth collision with environment
if (bCollideWithEnvironment && ClothingSimulationFactory && ClothingSimulationFactory->GetName() == TEXT("ChaosClothingSimulationFactory"))
{
    UE_LOG(LogSkeletalMesh, Display, TEXT("OnRegister%s]: " "Chaos Cloth does not currently support bCollideWithEnvironment."), *GetNameSafe(SkeletalMesh));
}


it’s not support

The upgrade is fantastic. A project loads with no hesitation and I can destroy the CG’s immediately. Thanks.

Sadly, global gravity still only affects characters and projectiles. Nothing else.

Here is a video Chaos426p1 - YouTube

This crash still happens in preview2.

You can reproduce crash by loading ‘SK_Veh_Car_Taxi_01_PhysicsAsset’ from ‘POLYGON City Pack’
https://www.unrealengine.com/marketplace/ko/product/polygon-city-pack

I have tried to debug this crash and found that ‘HorizonEdges’ array is already not in order from BuildHorizon() function.

Hi,

I’m trying to package my project with UE 4.26.2 Chaos version, and I’m having this error. (same as Actuss I guess)

UATHelper: Packaging (Windows (64-bit)): Building 2 actions with 20 processes…
UATHelper: Packaging (Windows (64-bit)): [1/2] PackageTry-Win64-Shipping.exe
UATHelper: Packaging (Windows (64-bit)): Creating library E:\UnrealProjects\PackageTry\Binaries\Win64\PackageTry-Win64-Shipping.lib and object E:\UnrealProjects\PackageTry\Binaries\Win64\PackageTry-Win64-Shipping.exp
UATHelper: Packaging (Windows (64-bit)): Module.ChaosVehicles.cpp.obj : error LNK2019: unresolved external symbol “private: void __cdecl UChaosWheeledVehicleMovementComponent::FillWheelOutputState(void)” (?FillWheelOutputState@UChaosWheeledVehicleMovementComponent@@AEAAXXZ) referenced in function “protected: virtual void __cdecl UChaosWheeledVehicleMovem
entComponent::UpdateSimulation(float)” (?UpdateSimulation@UChaosWheeledVehicleMovementComponent@@MEAAXM@Z)
UATHelper: Packaging (Windows (64-bit)): Module.ChaosVehicles.gen.cpp.obj : error LNK2019: unresolved external symbol “public: static void __cdecl UChaosWheeledVehicleMovementComponent::BreakWheelStatus(struct FWheelStatus const &,bool &,struct FVector &,class UPhysicalMaterial * &,float &,float &,bool &,float &,bool &,float &,struct FVector &)” (?BreakW
heelStatus@UChaosWheeledVehicleMovementComponent@@SAXAEBUFWheelStatus@@AEA_NAEAUFVector@@AEAPEAVUPhysicalMaterial@@AEAM414142@Z) referenced in function “public: static void __cdecl UChaosWheeledVehicleMovementComponent::execBreakWheelStatus(class UObject *,struct FFrame &,void * const)” (?execBreakWheelStatus@UChaosWheeledVehicleMovementComponent@@SAXPEAVUOb
ject@@AEAUFFrame@@QEAX@Z)
UATHelper: Packaging (Windows (64-bit)): Module.ChaosVehicles.gen.cpp.obj : error LNK2019: unresolved external symbol “public: static struct FWheelStatus __cdecl UChaosWheeledVehicleMovementComponent::MakeWheelStatus(bool,struct FVector &,class UPhysicalMaterial *,float,float,bool,float,bool,float,struct FVector &)” (?MakeWheelStatus@UChaosWheeledVehicle
MovementComponent@@SA?AUFWheelStatus@@_NAEAUFVector@@PEAVUPhysicalMaterial@@MM0M0M1@Z) referenced in function “public: static void __cdecl UChaosWheeledVehicleMovementComponent::execMakeWheelStatus(class UObject *,struct FFrame &,void * const)” (?execMakeWheelStatus@UChaosWheeledVehicleMovementComponent@@SAXPEAVUObject@@AEAUFFrame@@QEAX@Z)
UATHelper: Packaging (Windows (64-bit)): E:\UnrealProjects\PackageTry\Binaries\Win64\PackageTry-Win64-Shipping.exe : fatal error LNK1120: 3 unresolved externals
UATHelper: Packaging (Windows (64-bit)): Took 7.507629s to run UnrealBuildTool.exe, ExitCode=6
UATHelper: Packaging (Windows (64-bit)): UnrealBuildTool failed. See log for more details. (C:\Users\Aron\AppData\Roaming\Unreal Engine\AutomationTool\Logs\D+Program+Files+Epic+Games+UE_4.26Chaos\UBT-PackageTry-Win64-Shipping.txt)
UATHelper: Packaging (Windows (64-bit)): AutomationTool exiting with ExitCode=6 (6)
UATHelper: Packaging (Windows (64-bit)): BUILD FAILED
PackagingResults: Error: Unknown Error

I get this when trying to package vehicle template or any project with chaos vehicles, other templates or projects without chaos vehicle can be packaged normally. Also, it can’t be packaged only on shipping configuration.

Hi,

I have been testing the Chaos build from the launcher and am seeing objects fall through the floor, if that floor is quite thin. Here is an example video:

Here’s the test project from the video: https://iamestranged.com/distribute/…lisionTest.zip

This could happen with PhysX, but when you turn on CCD with PhysX it fixes it - that doesn’t seem to be the case with Chaos!

I can reproduce this with a plane, but it also reproduces with Engine/BasicShapes/Cube with a scale of 10, 10, 0.05.

Will this limitation be addressed in later versions?

Thanks!
Alan

Last I checked they hadn’t implemented any form of CCD for chaos yet.

I noticed a few bugs/problems related to Chaos Vehicle.

  1. Chaos Vehicle does not like driving on Spline Mesh Components. It looks like wheels cannot decide on what spline mesh collision primitive they are, and they are very jittery, and can jump into the air… Setting the mesh collision to “complex as simple” fixes the problem.
  2. When vehicle is teleported it can easily stuck in the air while falling. (it can also happen when you jump)
  3. Origin Shifting does not work with vehicles (and any other skeletal meshes, as far as I know)
  4. When vehicle wheels are not touching the ground, you can’t increase RPM, and wheels are not moving
  5. When you park your car next to a STATIC obsticle and try to push it, your wheels should start to slip in place, and that happends when car have enough power (which is good). The problem is that your wheels suddenly stops every few seconds for some reason. And because of that it is impossible to do “burnouts”. I think that they stop when you reach max RPM, but I may be wong about that.
  6. When you turn, and your front wheels starts to slip, they suddenly turn more that they should at given speed.

Other than that, I think that Chaos Vehicle is much better than old PhysX Vehicle. It feels much more “real”.

Edit: I have some more problems:

  1. Vehicle does not want to move when it is not on a flat surface
    8 . Vehicle slowly moves even with no input
  2. When the vehicle is rolling, it can go uphill with no problems (even on VERY steep slopes)
  3. It also does not speed up when going downhill.
  4. It even looks like the vehicle speeds up when going uphill, and slows down going downhill, but it depends on slope.

Please, help us with the problem below in this version! UE4 has been crashing for a while now - after every few minutes of use for the past 6+ months. Dunno wth happened, but there is a problem with the new windows/nvidia driver updates and the only way that seems to have fixed this issue is to have nvidia drivers from last march.

https://forums.unrealengine.com/unreal-engine/feedback-for-epic/1722586-unreal-engine-is-exiting-due-to-d3d-device-being-lost-again-and-again

I tried to submit a bug, but since I didn’t receive any response for more than a month (maybe it’s fine), I’ll write about it here too.

For some reason Chaos Vehicle Movement Component not work if it placed in a separate module of the vehicle.
For example, I have a master vehicle blueprint, which initializes various modules (like chassis with vehicle component, weapons, etc) at runtime
With PhysX, there were no issues when you spawn a module with a vehicle movement component at runtime. But with Chaos Physics in a similar setup vehicle simple not moving and I don’t know why since there are no errors/warnings.

I made a test project to show what I mean: ChaosVehicleTest.zip - Google Drive
Maybe it’s not a bug and I’m doing something wrong. If so, please tell me.

Installed Preview 2, Testing.