Why are GPU particles scaled wrong with render targets?

Development Asset Creation FX
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1

We notice that GPU particles scale wrongly when they are captured by render targets.
Is this a bug or is there something we’re doing wrong?

All post process settings are set to default.

Here’s a picture showing the issue;

http://puu.sh/94uBd/a57e3054b3.jpg
render texture (left)
in-game render (right)

2

Hi bigzer -

I am not able to reproduce the effect you are showing us in your screenshots. Could you possibly upload screenshots of your particles setup or are you using a sample system already in the engine?

Thank You

Eric Ketchum

3

Hello Ketchum,

On this particular picture we’re using P_Dust_Particulate_Ambient from the elemental demo.
We notice it also happens on P_Sparks from the standard assets. The GPU emitter called spark becomes huge and the GPU emitter called smoke as well but not “spark burst” (CPU). Its the reason why I think this problem is linked to GPU particle only.

We are running on windows7 and the editor is the standard build 4.1.0

4

Hey bigzer -

Still no luck at getting this problem to reproduce using either the Dust from Elemental or with Spark. Have you tried to reproduce this error in version 4.1.1 or, more importantly, in a new project. I still think I am missing a step on how you have the setup functioning.

Let me know -

Eric Ketchum

5

Hello Eric,

4.2 Fixes the GPU particle scale issue :slight_smile:

Sorry for the delayed answer.

Best regards
Bigzer

6

Eric actually its not fixed but we found how this happens;

Change the render target to something small!

To reproduce;

  1. Set the render target resolution to 512x512
  2. Look GPU particles through the render target and you will notice the huge particle size.

Can you confirm you manage the reproduce it?

7

Hi bigzer -

I’m still not able to reproduce this effect and I’ve used the P_Ambient_Dust particle system and a custom GPU particle system with the Render Target set to 512x512. In both instances my particles were sized correctly in the Render Target. What is the settings of you Scene Capture 2D actor?

Thanks

Eric Ketchum

8

Hello Eric,
sorry for the late answer but the problem is gone and we are now unable to reproduce it. If we see it happens again and if we can reproduce it I’ll let you know and perhaps give you a repro project to download.

Best regards
David