Retime large scale Pyro

[blackchicken]

Hello I have little problem an Im little bit confusing. I have really large scale sim, say 150frames (days to simulate) there is a link 3 same sims together just for render tests:

now I need retime it.

I need animation say 1-200 which original should be from 120 to 150.I need really really slow motion of heavy pyroclastic smoke. I read all I could but cand figure it.

1, Scale time in pyro. Works but problem starts when you animate time parameter, slo-mo loose all details from shredding and all stuff like that.

2, SOPs with volumemix, nice way but fluids jumps.

3, Use upres and scale time but. I export, temperature, density, vel. in "low" But if I need slo-mo I but I need simulate over 2000 frames to get where i could use it for my purpose.

It is posiible use rest position in dops or whatever to simulate just Hi sim in really slo-mo? What is you favourite setup? Thanks a lot......BC.....

[sam.h]

I did this a few months ago using DOPs and advection to interpolate in between frames and it worked really nicely .... I will try to post an example tonight for you but basically the idea is:

- get the density and vel volumes

- timeshift to floor($FF) (just in case there is some blending that is going to interfere)

- make an attribute that records $FF, call it sourceFrame or whatever

- timeshift to your target anim (fit($FF,1,200,120,150) or so)

- load these into a *timeless* dop net with sopscalarfield and sopvectorfield

- use an advect volume node to move the volume, using frac(sourceFrame) as a multiplier for the advection

and thats it, get the volumes back into sops and it should be all good.

[blackchicken]

I did this a few months ago using DOPs and advection to interpolate in between frames and it worked really nicely .... I will try to post an example tonight for you but basically the idea is:

- get the density and vel volumes

- timeshift to floor($FF) (just in case there is some blending that is going to interfere)

- make an attribute that records $FF, call it sourceFrame or whatever

- timeshift to your target anim (fit($FF,1,200,120,150) or so)

- load these into a *timeless* dop net with sopscalarfield and sopvectorfield

- use an advect volume node to move the volume, using frac(sourceFrame) as a multiplier for the advection

and thats it, get the volumes back into sops and it should be all good.

Thanks a lot thats sounds really cool. If you have some sample scene I would love to explore it because Im still new in advanced DOPs. Thanks a lot again.

[blackchicken]

So I tried setup from sam.h. Interesting idea but simulation is steppy. If there is somebody who has some good workflow how to retime large pyro sim, Ill much appreciate. Thanks a lot.

[Pazuzu]

So I tried setup from sam.h. Interesting idea but simulation is steppy. If there is somebody who has some good workflow how to retime large pyro sim, Ill much appreciate. Thanks a lot.

You can use an uprez stage to do the retime (look in the example files of the houdini help), the problem is that because it resim all the combustion stage maybe the sim can change a lot.

[almatea]

[sam.h]

If anyone else is interested, this is the example file ... kind of works ....

https://docs.google.com/file/d/0B1hcC7UTpSs5d2pRU0NOYnNuMWs/edit?usp=sharing