Flickering when using stretched particles

Question

When I'm trying to use large amounts of stretched particles they screen seem to flicker slightly in higher resolutions, as if they all disappear or darken for a single frame. I can't quite grasp what happens exactly - the effect is very subtle, but bad enough to give up on the stretching altogether. I don't see it happening when rendering into a small window next to the editor.

May be I misused the stretched particles though. They aren't animated, but hang in place as player walks inside a cloud of points. They are supposed to appear and stretch due to the camera movement.

Answer 1

Answer by Statement · Dec 24, 2010 at 12:09 PM

Try changing particle render mode. I know I had this problem some long while ago back in 2.6. I think the culprit was the rendering mode, but I don't know which one it should be. Fiddle around with the settings a while and see if you can solve it.

Sorry, my answer is a bit vague.

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femi · Dec 24, 2010 at 12:19 PM 0

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But the problem I have is with the rendering mode I want :-) I do want particles to stretch as I go exactly as "Stretched" mode does it. But I think may be I miss something. It's like now and then it would skip a frame and something is reset in the stretch shader.

Statement · Dec 24, 2010 at 12:29 PM 0

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Could you try to position the camera near the exact location where it happens and gently jiggle the camera around a bit there? Is it linked with angle of observation?

femi · Dec 24, 2010 at 02:39 PM 0

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It happens everywhere, I just demoed it with the pillar because it's white and the flicker is best visible there.

femi · Dec 24, 2010 at 02:49 PM 0

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Just found how to trigger the glitch reliably in low resolution: http://vimeo.com/18149430

Statement · Dec 24, 2010 at 03:03 PM 0

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I guess you can easily rule out the render settings if you attempt to reproduce the error in a blank scene without the open scene graph code, just have a big partcile system with the same settings.

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Answer 2

Answer by Jozxyqk · Oct 14, 2012 at 03:06 PM

I know this is quite old but I just hit the same bug. My answer is that Camera.velocity (which I can only assume is used to stretch the particles) is calculated as the position delta between every Update. If some object only moves during FixedUpdate, as default rigidbodies do, then the velocity is scaled by the amount of FixedUpdates. If the position changes with mouse movement, some frames may give zero movement.

A quick fix for the rigidbody case is to set interpolation. In general some sort of interpolation or smoothing must be done.

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Flickering when using stretched particles

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