"NO ASYNC TICK" error in Cascade viewport?

Hey guys. I’m trying to make a particle system that’s intended to emit from the shape of an animated character. I believe what I need to make this happen is the “Skel Vert/Surf Location” module on my particle emitter, but I’m getting a strange “NO ASYNC TICK” error. The only other place on the entire internet that I can even find this error message is this unanswered question on the answer hub. This error appears when I create a brand-spanking-new Particle System and simply add the Skel Vert/Surf Location module, and no amount of fiddling with properties, short of disabling the module, gets rid of the error. Other Location modules work perfectly well.

Here are the settings I’m using. Again, the error appears after making a brand new Particle System and adding the module - even before setting the Editor Skel Mesh as I have in the screenshot.

Any idea what the problem is or how I can get around it? UE 4.22.0


I can confirm that I get the same thing - on a new PS on my build too when adding a Skel Vert/Surf Location module. I think this must be new to 4.22 because I’ve used that module a lot previously and never got that message (I don’t think it’s an error).

I’ve seen this pop out recently when setting “Apply Physics” to true in the Actor Collision module. In that instance it means the PS won’t run on the game thread - I guess it instead runs on the render thread. So I’m also guessing it means the same thing applies to the Skel Vert/Surf Location module.

I noticed they set “bEnableAsyncScene=False” in the DefaultEngine.ini when you upgrade to 4.22. Maybe it has something to do with that?


Unfortunately, it seems that beam particle modules don’t support async ticking at all. Looking at ParticleModuleBeamBase.h CanTickInAnyThread() that just returns false:

UCLASS(editinlinenew, hidecategories=Object, abstract, meta=(DisplayName = "Beam"))
class UParticleModuleBeamBase : public UParticleModule

    //Begin UParticleModule Interface
    virtual EModuleType    GetModuleType() const override {    return EPMT_Beam;    }

    virtual bool CanTickInAnyThread() override
        return false;
    //End UParticleModule Interface

For any one still getting this error. Download 4.2. Build your cascade there and then migrate it to your >4.2 project. In my tests this worked.