Particle System Rendering Bug

I created a scene as shown below. It consist of 2 planar objects + 1 particle system (fire).

The position of the particle system is actually in the middle as you can clearly see.

But somehow when I played it in a separate window, it does not render correctly from a certain angle as shown below. From the left angle it is correctly shown. But from the right angle, it’s shown in front of other objects. Is it a bug in UE4?

Hey Pelangi,

This could be a Translucent Sort Priority issue. Are either of your materials, for the particle and for the ground plane mesh set as translucent?

If possible, could you provide me with this test project or some repro steps so I can take a look on my end?

Thank you,

Andrew Hurley

I’m using the same material for fire in the starter content folder, but I made them to “UNLIT”. And also, I created my own version of fire particle system, which is quite similar to the one in the starter content folder, because I’m learning how each emitter and modules affect the entire particle system. You can download my entire content folder here:

I actually use starter content folder, but I don’t include it in the upload, because it’s too big. For this specific bug, I didn’t change any coding. I just used the 3rd person template and removed many default objects. I hope this information is enough for you.

Hey Pelangi,

As I suspected, the issue here is the Translucent Sort Priority. As soon as I set the values for Translucent Sort Priority each of your meshes placed in the level to sort correctly, i.e. background to foreground, 0 to 3 since you have three translucent objects lying on different locations along the X-axis.

Click on your fire particle and within the Details panel, rollout the Rendering dropdown and set the TSP to 1.0. (use the image below as reference). You can then select the foreground mesh and set its TSP to 2.0.

Translucent Sort Priority

Correct Sorting

As you can see, as soon as you have the sorting correctly established the fire particle renders correctly. Let me know if you have further questions or need additional assistance.


Andrew Hurley

Yes Andrew. It solved my problem. Thanks a lot!