How to set initial color GPU particle parameter from blueprint?

Development Programming & Scripting Blueprint
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1

My Setup at a glance:

16875-cascade+gpu+wtf.jpg
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Not sure if this is a bug or not, but I cant set the initial color of the GPU particle from within a blueprint script.
the colors change when i set the constant values in the components tab and when i set the constants in cascade, but if I set it by calling either the set color param or set vector param in blueprint (or both as seen in picture), absolutely no change occurs.

Am I doing anything wrong?

2

Hey xdbxdbx -

I have entered this bug in with our engineers for further investigation and I will let you know when we have a solution. The report is listed as UE-5168.

Thank You

Eric Ketchum

3

This is pretty old and appears to still be unresolved (as of 4.7 at least). I just had 2 hours of confusion before finding this report. Any news?

4

Funny, I’m having the same issue right now, too. I’m using a Ribbon emitter and have it set up exactly the same as the OP. It’s drawn as black regardless of what color I input.

5

Same here to on 4.9.2. I’m trying to use a Distribution Vector Particle Parameter but it’s ignoring whatever the parameter is set to.

6

Hello Everybody -

When using the Particle Parameter that you will want to set directly from Blueprints, please make sure that your Particle Parameter Mode is set to DIRECT.

65678-parammode.jpg
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Thank You

Eric Ketchum

7

That isn’t working neither on 4.10

8

Hello Ivan -

Are you setting the ParamModes to DPM Direct and making sure that you are setting the value in your Blueprint?

Internally this functionality is working correctly.

Eric Ketchum

9

for me it is not working as well.

tried to call GetVectorParameter or GetAnyVectorParameter with my parametername but i get false as a result which leads me to think the parameter is not there at all.

10

Hello -

Using Initial Color with GPU Particles is still a known issue as of 4.11 Preview 6. I have included additional information to the bug report, UE-5168.

However there is a workaround:

  1. Set your Initial Color Module to a Constant 1,1,1
  2. Add a Scale Color / Life Module
  3. In the Color Scale Over Life set the Distribution to Vector Particle Parameter
  4. Name your parameter in Parameter Name
  5. Under Param Modes set the 0,1 and 2 all to DPM Direct
  6. If needed, set the Constant RGB values to 1,1,1 (will not affect outcome.)

You should now be able to control the Particle Parameter in your Blueprints. Remember you can also stack the same module more than once, so you can add another Scale Color / Life Module to control overall behavior over the particles life, if required.

I have attached a sample project below showing the setup mentioned above.

Thank You -

Eric Ketchum

Test Project 4.10.4

1 Like
11

thank you very much.
tried to get my particle effects colored for 3days with initialcolor but i can stay sane now thanks to you. it worked

12

Just a small supplement: Don’t use “Initial Color” at all, instead use “Color over life” with parameters for initialization (as described above). And add “Scale Color / Life” after that module to add some non-parameter information if you want (especially distribution curve).

Furthermore, this bug will probably not be fixed (status “won’t fix”, see UE-5168), so you have to use this workaround.

13

The bug still exist and it has marked as Won’t Fix because it has been so long!

Now that workaround only works if you want all particles the same color at the same time. Considering defining a color is a basic thing of a particle system it would be much appreciated if anyone can fix this issue.

I have not tested yet if the same bug exists with Niagara, maybe if its working there the fix can be taken over for the regular particle systems.

14

Hi,
I know that is a old post, but maybe someone want a solution to this problem.

I have this workaround,
instead of using a “Initial Color” module, I use a “Color Over Life” module,
and it work.