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I makde a ribbon particle, normally it will look like this,

but sometimes,it will display error like this:so what's wrong with this particle?

asked by skatebill (190 points)

2 Answers

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I don't think it comes from the ribbon. Ribbon are just a way to display particles with links between them.

The problem comes from the "placement" of your particles themselves.

I'm guessing something is not frame rate "stable". Try to play with the FPS limiter (viewport toolbar 11: http://wiki.popcornfx.com/index.php/Particle_editor#Top_toolbar).



answered by Jordan (14.6k points)
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Hi there, 

A bit late now - but I noticed that this happens over the course of the ribbons life when the lifespan of the ribbon particles is not consistent, e.g:
Life = rand(1.0,2.0); 

when a particle in the middle of a ribbon dies while its neighbors are still alive, it seems that the ribbon self-corrects by skipping the dead particle and joining the two neighbor ribbon particles in the chain, creating a break in the flow of the ribbon particles that often results in jarring straight lines, also it will pick a new TextureID for that section if you are randomizing that in creation, again jarring.

You can really exacerbate this effect with a more one-sided lifespan:
Life = select(0.02,0.4,ninja<0.1);

I fixed this issue in my case by making the lifespan of the ribbon particles consistent, e.g
Life = 1.0;

If you are doing multiple ribbons from trail evolvers and wanted some randomization in Life, you could always set a random field on the parent, eg 
RandLife = rand(1.0,2.0);
and then set the life of the ribbon particle to inherit the parents field:
Life = parent.RandLife;
This will randomize the life between different ribbons but not within the ribbons themselves.


answered by simonb3d (480 points)
This is an excellent point simon.
In skatebill's case though, I don't believe this is the problem, as the wireframe view would have shown a single strip across the "jump", whereas here, we clearly see there are many sub-strips, meaning the particles across the jump are still alive.

But indeed rand lives for ribbon particles will do what you described. (and it's normal behavior)
Fixing that by using a parent field to still have randomness is a good idea !