How do I add extra points in a particle trail?

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Hi, I am making a simple dust trail setup for an RBD sim that I made. The problem is that I can't get there to be a good tight spacing of particles to source from; there are huge gaps in the particles which gives bad stepping in the dust sim (image below).

I really have to the this finished this week so it is crucial that I find a solution (and im sure it is a beginner problem but im up against a wall here). Thanks!

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Screen Shot 2019-03-20 at 10.01.42 AM.png (124.6 KB)

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What you are experiencing is a stepping issue. Your points that are sourcing the particles are moving too quickly, which creates the gaps between the particles. What I would do if I were you, is add a trail to the source particles, that is long enough to fill the gaps - that way every frame, you source enough particles to fill the gap, as opposed to just the current particle at the source.

Or, you can give each source point a class, then every particle that is born will retain that class. Use a for-each loop to isolate each “trail” according to class, then add a line for every trail. Once you have a line representing every trail, you can resample them as much as you want, to fill in the gaps that way as well.

If you want this resolved in your scene, post a hip file and i'll check it out.
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Hey thanks for the suggestions! I did actually try the trial thing but it didn't work for me. Here is my file: . Let me know if it works for you.
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I see they try to not let you post links so lest try it this way:Your text to link here… [www.dropbox.com]

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There are various ways around this. Have you turned up the substeps on the POP solver? Making it two or three will help. However, if your source is a file cache, this won't help as there are no inbetween frames. If the source has increasing point count only, (no dying), you can use a file cache with blend point postion on and $FF as the lookup. Then the substepping will work.

If you can't do that, you can always do the substepping thing and/or increase the number of particles emitted. Now your points are on top of each other, so you will still see stepping. Now just smear them along the velocity vector. Add a wrangle with:

@P+=rand(@id) * @v;

P.S. You can attach hip files to the forum.
Edited by mrCatfish - March 20, 2019 15:20:56
Sean Lewkiw
CG Supervisor
Machine FX - Cinesite MTL
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Please see the attached file. If you have any questions about it, let me know. But as you can see, I've made your trails a lot more dense with the trail sop. The thing you probably didn't use was the timeblend sop, which is necessary for interframe data.

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Point_problem_01.hipnc (138.6 KB)

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Im kind of confused; this looks just like what I had. Wont it still step in the pyro sim?
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?

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Try this

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Point_problem_02.hipnc (136.3 KB)

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Pic for reference
Edited by Midasssilver - March 20, 2019 15:47:45

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trails.png (324.1 KB)

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