Resolved - Untiy 6 Particle Trails: Minimum Vertex Distance has no effect below 0.1 value

Unity Engine
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1

Hello,
We’ve recently upgraded to Unity 6 Preview, and I’m having a problem I didn’t encounter yet in other versions: on the built-in particle system trail module, the Minimum Vertex Distance setting doesn’t have any effect on trail smoothness below a value of 0.1.

In other versions, I could set it to really small values to get a very smooth trail (at a performance cost, I’m aware), but in 6, the trail poly number stays the same no matter if the Minimum Vertex Distance is set to 0.1 or 0.001.

Is this a bug or am I missing something?

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I’m not sure why it would be different between versions, (nothing much changed in this code) but it’s worth noting that this setting would only ever be able to add 1 point per frame, so maximum smoothness is heavily dependent on framerate. Perhaps something has made your framerate much worse in Unity 6?

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It’s apparently a bug and has been added to the backlog by the Customer QA Team. Apparently it has been around for quite some time:
“Reproducible with: 2021.3.40f1, 2022.3.40f1, 6000.0.13f1”

4

Thanks for the bug report.
Someone from the team will look into it.

I am still curious if the trail might be limited by the framerate, in the problematic case.
If the trail is moving slowly enough relative to the framerate, I would of course expect values less than 0.1 to work.

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5

In the empty test project, we’re at min 400fps in the mostly empty test scene.
Additional info: it’s not exclusive to Unity6 as I originally assumed, as it also happens on another test project in Unity 2022.3.

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6

Aaaaaand you were right. Once I removed V-Sync, there was a notable difference between trail resolutions. Took my some time to find the switch, sorry for that!
I’ll add additional info to the bug ticket, which is not a bug after all…

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7

Thanks, glad you figured it out!

There is an AddPosition script API for adding sub-frame positions, but it’s not easy to know where the new points should go. It depends on your use case. You’d need to know, for example, that the trail was spinning around some central position, or following some animation path, in order to know where the extra positions should go.

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So mark it as resolved and give the guy some credit!

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9

Thanks for the reminder. I’m new to the forums and didn’t think of it.

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