Global Velocity Control For Pop Nets.

[ofer]

Hello.

I have created a POP network, which contains particles with initial speed and two force POPs. The overall simulation is very good, and the particles movment is timed very well in the viewport.

My problem is that when I render the sequence it is very fast and the particles are barely seen.

I want to slow them down.

I know the drag POP, but this is not what I mean. Is there any way to maintain exactly the same movement, only slower?

Is there a simple trick to do it?

Thanks.

[Overload]

You could try the speedlimit POP...or create a variable and divide all your forces by that so its all equal... just off the top of my head

[old school]

One option: build your pop network inside a DOP network and use a POP DOP and POP solver. You can use the global time scale parameter on the DOP network top Root Node's parameter to slow down or speed up the pop sim.

See attached file. There are a couple critical steps that are outlined in the comments on some nodes. Look for the blue node names!

The old school standard way to slow down a particle sim is to generate sub-frames and either write geo files out to disk then read them back in or to render subframes. render using integer frames instead of whole number frames.

See the attached file. I put a second object in there with a simple particle sim that uses ROP Geo SOP to write out the particle sequence at whatever increment I want then read them back in with a File SOP. Just hit the render button to generate the particle geo sequence.

Old School rules!

pop_global_speed.hip.zip

I personally put the majority of my particle networks in DOPs now. Not only can you completely control the speed of the sim, you can also scrub the playbar back and forth. You get the added benefit of real instance collisions plus collisions with other objects in the scene in DOPs instead of POPs or both. Lots of flexibility.

[ofer]

Well, this looks very close to it. I need to check this HIP more closely.

Thank you very much.

[jhiggins]

Well, this looks very close to it. I need to check this HIP more closely.

Thank you very much.

along the same lines as ofer, but not having to get into dops as much.

you can cache your particles to disk and when you read them back in you can

retime them with a little expression on the frame number.

just another idea

you should also be able to use the CHOPs as well to retime particle sims although,

i'm a bit sketchy the details (Particle CHOP and Lag CHOP come to mind).