Emitting particles along a 3d path for time-lapse

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@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.

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You are using the “Pre” option correct?

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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

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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.

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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

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@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.

right?

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(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

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

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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

Cheers

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

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