Why are my Particle module curves not behaving as expected in my Ribbon module?

Hi,

I made a energy trail particle using Ribbon data but I’m having a problem when I put a module with a curve that is dependent of the lifetime.

I’ve put a Size by Life Module with a curve that goes form 0 to X Within the Lifetime, but when I test the initial size isn’t 0 and appears to keep variation with current frame rate.
Other very clear result of this problem is when I use slo-mo, in the same moment that I use it, the Particle initial size becomes smaller.

The particle is attached with my character and keeps in movement, Its lifetime is 0,6 seconds.
The same happens with Color over Life module.

Here is the screenshot of the cascade:

Hey Luke -

Some quick questions on your setup: Have you setup the Ribbion with SpawnPerUnit? Are you using a Constant Curve or a Uniform Curve in the Size and Color over Life? What is the In and Out value for your points 0 Size by Life module?
And finally, can you post a screenshot of your Cascade setup and of the actual error for reference?

Thank You -

Eric Ketchum

Hello Eric,

I’m using SpawnPerUnit and Constant Curve.
Here is the screenshot of the the trial without slowmo and with slowmo.

And when the particle activates while in slow mo it begins even smaller:

Hi Luke -

I want to get some clarifications on the slow mo aspect. Are you doing this via a function in the game or are you using a developer tool to view in slow motion? If it is function you have placed in your game, how are you calling time? Are you actually slowing the game time down?

Let me know -

Eric Ketchum

I’m using the Time dilation function, with a value of 0.2.
But The problem is not only with the slow mo, whenever you have a variation in FPS it messes with the curve.
I think for some reason it’s having difficulties to calculate the curve.

Hi Luke -

I think I might have tracked down a solution for your dilemma here. Since you will be using this particle system with time dilation this effects any relative modules which use game time (anything “/ or By” Life) you will want to change the module for Size by Life to Size Scale and just use Color Over Life alone without the Scale Color / Life. You will probably have to make some size adjustments but you your system should no longer change based on the game time dilation.

Let me know if that works or if you are still having an issue -

Eric Ketchum

Eric Ketchum,

Unfortunately that don’t helped me at all. I already tried all possible modules combinations and ever get the same results.
And even desconsidering the Slow-mo function, we still have the fundamental problem: the particle curves are varying too much with the frame rate. When the frame rate drops the curve that should start with 0 do not behave correctly.

Hi Luke -

The frame rate should not be affecting the particles in that way, if your frame rate is dropping the system should be rendering more slowly, but not decrease in size like you are experiencing. Can you upload the DXDiag from the CPU you are running on as well as the CPU Specs?

Thank You

Eric Ketchum

Intel(R) Core™ i7-3610QM CPU @ 2.30GHz

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Hi Luke -

Can you try to set the following info in your Config\DefaultEngine.ini file and see if you are still having this issue?

[/Script/UnrealEd.EditorEngine]
bSmoothFrameRate=true
MinSmoothedFrameRate=5
MaxSmoothedFrameRate=60

Let me know -

Eric Ketchum

Hi Eric,

Unfortunately that didn’t make any difference too…

Hey Luke -

Unfortunately I think to continue helping I may need access to your original assets, the particle system and character setup. If you are willing to share or can reproduce this same effect with test assets and upload them through a Dropbox

Let me know -

Eric Ketchum

I also have problems with the ribbon particle. Which i think should be easy to reproduce. Problem1: Have a ‘particle relative time’ node in the material editor and plugging it directly in the opacity doesn’t give you what you expect.
Problem2: make the lifetime of the ribbon a particle parameter then set it from a blueprint and nothing changes.Just setting the lifetime by itself doesn’t seem to do anything.
Problem3: which is similar as discribed above. Have a normal initial sized ribbon then add a size by life module with a few points and make the first point time:0 value: 0,0,0. You’d expect the ribbon to start out as nothing and grow to a normal size but that doesn’t happen either.
It seems the ribbon particle is broken or either doesn’t make any sense at all.