how to make a particle loop?

[cloudfx]

Hi,

 

Is there any known way to create looping particles?

 

E.g. if I set to simulate 1~80 frames of particles it will be loop-able from 1-80 over and over again.?

 

 

[woodenduck]

The exact same animation? You can add a Timeshift after the popsim back in sops and set the Frame parameter to $F%80.

[Matt_K]

If you mean a seamless loop for stuff like rain/snow/embers etc, it is doable but requires a little work.

 

For around 80 frames, you can sim to frame 40 (or longer if you need an overlap), then use that frame as the initial state in a new sim of equal length.

Cache out the two sims and combine (merge & timeShift/timeWarp) them in SOPs.
Have the second sim running first so that your second sims first frame, and the first sims last frames match. 

 

Then the trick is to fudge the join :

• try an overlap with a blendShape (sometimes works)
• just an overlap can work too if it's enough so that no visible "pop" is evident - usually works with rain if it's fast/heavy enough
• or use the pscale attribute in an attributeVOP (with lots of randomisation) over a few frames to scale the one sim out as the other scales up - usually good for snow / embers
• or just get lucky with sims that just work

If you get the loop to work, you can cache that out and then cycle it when you read it back in using a timeWarp SOP.

 

Hope this is of some help!

Matt.

Edited January 6, 2016 by Matt_K

[pupps09]

On 2016/1/7 at 6:13 AM, Matt_K said:

• try an overlap with a blendShape (sometimes works)
• just an overlap can work too if it's enough so that no visible "pop" is evident - usually works with rain if it's fast/heavy enough
• or use the pscale attribute in an attributeVOP (with lots of randomisation) over a few frames to scale the one sim out as the other scales up - usually good for snow / embers
• or just get lucky with sims that just work

 

Hi. Is there any possibility you can post a hip file with any of the above techniques?

I tried using Peter Quint's method on looping flames, but apparently that method doesnt work with particles.

I've attached a hipfile with my failed attempt. Any help would be greatly apprecreciated. Thx!

 

loopPart_v01.hipnc

Edited April 29, 2017 by pupps09

[Matt_K]

Hi Naoki,
Will try and get an example for you a little later on today.

Matt.