How to enable Chaos

Can I use Chaos in 4.25.3 retail? The plug-in is installed per default (ChaosEditor Beta 1.0), but there is no ‘Fracture’ mode avail! Help!

Chaos is in 4.26 p3(launcher). It is working OK. A little slow with GC with large number of fracturing. Here is my youtube link. Euler Sosa - YouTube

Thanks. The issue I have, need to wait for the stable 4.26 release. Just wanted to add some destructible meshes, but not even the old APEX feature is available in 4.25.3, and the documentation page is not updated either. @VictorLerp

The plugin isn’t installed by default in 4.25. You need to :

  • Download 4.25 on Github and place it in a folder that is close to your disk’s root (if the path is too long, the download/compilation will fail)
  • Modify the UE4Editor.Target.cs file located in YourDisk\YourPathToTheEngine\UnrealEngine-4.25.3-release\Engine\Source\UE4Editor.Target.cs by adding these lines to build & activate Chaos :

bCompileChaos = true;
bUseChaos = true;

**I did not follow the documentation, I did not replace

BuildEnvironment = TargetBuildEnvironment.Shared;


BuildEnvironment = TargetBuildEnvironment.Unique; 

because it doesn’t work.**

  • Build the engine
  • Launch it from Visual Studio by debugging or use YourDisk\YourPathToTheEngine\UnrealEngine-4.25.3-release\Engine\Binaries\Win64\UE4Editor.exe and create a new project
  • This is normal if you can’t launch the project. In this case, open the file YourDisk\PathToYourProject\YourProjectName\Source\YourProjectEditor.Target.cs and add :

bCompileChaos = true;
bUseChaos = true;

(That’s another thing you can’t find in the documentation…)

  • Save the file, restart the editor, launch the project, and then you have to go in the plugins manager to activate all these plugins :

  • Chaos Editor

  • Chaos Solver

  • Chaos Niagara

  • Planar Cut

  • Editable Mesh

  • Geometry

  • Geometry Cache

  • Field System

    • Restart the editor to activate the plugins
    • Open the fracture mode using the buttons I circled in red in the screenshot.

About using it for a project, it’s not recommended in 4.25. Use 4.26 instead.

@Rainoxer Thank you for the detailed rundown, though I will wait for stable 4.26 until i touch Chaos.

After an update I can’t see FractureEditorMode in 4.26 preview 7 anymore (plugins are checked), anyone else having this problem?

Chaos is not available in the 4.26 binary (launcher) versions - you’ll have to compile the engine from source. Steps and documentation can be found in the OP.

Are physics collisions between static meshes just not working currently in the source build? They all have no collisions with each other, only geometry collections collide with other geometry collections and static meshes.

Why they remove this tab last update?

I want to save the simulation results as a static grid, can it be convenient for me to create some broken assets

What are you calling “the OP” ?

The Chaos documentation is broken, open this link and try to click on “Starting out” or “Further reading” : Chaos Destruction | Unreal Engine Documentation

OP can mean “Original Poster” or “Original Post” - In this case I’m referring to the first post in the thread :slight_smile:

Thanks - I’ve let the docs team know. For issues related to our documentation, you can post on the Documentation Feedback channel: Documentation Feedback - Unreal Engine Forums

Assuming you still have to build chaos in source even in the official 4.26 build?

I’m on version 4.26.0 and in newly created project isn’t avaiable Fracture Editor in Modes menu. Other Chaos stuff are normally available, only Fracture is missing for some reason.
I checked enabled plugins - all required Chaos plugins are enabled (including Fracture Editor), then I tried to create blank pure bluepring/ mixed C++/pure C++ project but without any luck.
Maybe I’m mistaken but according documentation and posts in UE 26 release thread it should work out of the box, yet it doesn’t work.
Is it bug or it’s intended and I really need enabled something?

Yes, you are mistaken - the binary Launcher Version does not include Chaos. You still have to compile 4.26.0 from Source as stated in the actual documentation Chaos Physics Overview | Unreal Engine Documentation and as far as i understand, it will be that way until Chaos is out of Beta.

One thing about 4.26 + Chaos source, we need to compile using TargetBuildEnvironment.Shared instead of .Unique.
If you compile with Unique the engine crashes with a lot of errors (Hololens, GarbageCollector, etcs), using Shared everything works fine.
I’ll post on Documentation Forum suggesting the change.

The only version of Chaos I can get work is in 4.26 p5. Your explanations are chaotic. My 2 cents.

I think the documentation here Chaos Physics Overview | Unreal Engine Documentation is very clear. The only thing is that you must not change the BuildEnvironment (in the doc there is written you have to change: “BuildEnvironment = TargetBuildEnvironment.Unique;” ) - dont do that else the compiled engine will not run. I have a running 4.26.0 (release) source build with chaos :slight_smile:

I changed it what was it before? thanks . I found it. It is compiling know.

It worked. Thanks for help. It took a little over 2hours. I have an I9 too.