Particle rendering problem with Water Planes sample content

Development World Creation
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1

Hi,

I am using the Translucent water BP that is available as part of the Water Planes sample project from the Learn tab.
My problem is that at certain angles, the part of a particle effect that has water behind it will not render at all.

The problem only occurs with the translucent water sample, which leads me to believe that it is caused by some kind of depth sorting issue, however with my limited amount of rendering knowledge I have not been able to fix it. I also haven’t been able to figure out why the rendering problem only shows up at certain locations above the water, and when viewed at specific angles.

In order to reproduce the issue, do the following:

  1. Create a new, blank project. Make sure you include the starter content.
  2. Add the Water Samples content to the project.
  3. Open the map TranslucentWater_Example.
  4. Drag any particle effect from the starter content into the map. For debugging purposes, I find that the P_Steam_Lit effect works best.
  5. Try moving the effect around a bit and you will notice that at certain positions and camera angles, it will only render the parts that have rock behind it. If there is water behind, it will not render.

I have uploaded a video that shows off the problem: - YouTube

I would very much appreciate anything that might point me in the right direction toward fixing the issue, as this has been bothering me for a couple of weeks now. I am not even sure if I should be looking into modifying the code for the particles or the water in order to get this resolved.

2

Hi there,

While I have not tested your exact setup, I have encountered the exact same issue with my own water material in the past. Luckily it is very easy to fix!

Select the particle system in your level, then in the Details panel scroll down to the Rendering section, and press the small down arrow to expand the advanced properties. In here you will find a field named “Translucency Sort Priority” that sets the order of transparent mesh/material setup. The higher the number, the higher the priority, so you want to set this to be 1 higher than the water mesh setting. If you didn’t already modify that value it will be 0 by default so setting the particle system to a value of 1 should be all you need to do.

Hope that helps!

1 Like
3

Hi,

That appears to have fixed my issue completely, thank you! Perhaps there is some kind of disadvantage to adjusting the Translucency Sort Priority manually (for example, if part of a particle effect is under water), but for now this will do just fine.