Emitting particles along a 3d path for time-lapse

@Sinan one thing i have been trying to figure out is particles existing from frame 1 along a 3d path using a light as the emitter. at the moment i’m having to have a much longer comp so the emitter can travel from 0% to 100% and then only use the back half once the emitter has reached the end and all the particles have been generated along the path.

You are using the “Pre” option correct?

generating particles pre 0 didn’t work as its all been driven by the emitter starting at 0% on the 3d path. thinking about it now i wonder if using an open spline as the emitter would work…instead of a light

What happens if you set Pre to 100. If I set smoke particles to a 3D Path and set Pre to 100, it draws on frame one along the path…or am I misreading your question? Rick Click and Download for 4k size.

i dont think i explained the question well. effect is essentially a long exposure light trail so I dont want any new particles to be generated after frame 1. need them all formed along the path, and needs to be in 3d space

@west used to do this for car ads a while back…particles, 3d path, using a 3D Tex period or O if Im not mistaken, then glowed it in comp. Set the speed to 0, and the Number of particles high enough to make it dense enough for ya.


(just moved this to a new topic such that our original poster on the particle thread gets the attention his thread deserves)

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thanks @randy , apologies for hijacking

no apology needed! lemme know how you get on with it.

Hi @MikeyBrown,
As far as I understand from the rest of the thread you want to create a 3D streak that is in place as the shot starts. If this is just a light trail that is in 3D maybe you can use another approach than particles as the one @randy suggested. Or an extended bicubic with a line as texture.

If you definitely want to go with particles, I would suggest this:
Use pre 100 on you particle setup and animate the emitter light on the 3D path with parameters 0% set at frame -100 and 100% and frame 0. This will create the particle trail before your first frame to render. The pre-calculation might take some time but then it will just stay in place.

I hope this makes sense



Thanks Sinan and Randy, yep makes sense…didn’t realise the start could be negative 0% so solves the issue

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