Hello!

How can I write disk cache with substeps of simulation?
:?:
I want to write simulation RBD to disk, and use this cache for fluid sim :?

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or, maybe, parameters (pos,vel, etc.) write in cache as vectors and interpolate in substeps, and I don`t need to save substeps?..
:idea:
sorry my bad english… ops:

have you tried the File DOP? seems like exactly the tool. It writes the state of your simulation out to disk. In the filename, the default counter is set to simulation time instead of frames.

cheers,
Abdelkareem

$F = Frame #
$FF = Floating Frame #
$SF = Simulated Frame #


You want to use $SF in your file path when saving out your files. You may also opt in to add frame padding (if you use 3, you will have your files named 001,002,003 … 100, 101, etc.

cwhatever_folder_you_save_to/filename.$SF3.sim

Thanks for answers, Im use $SF3 and I have 001,002,003… files, frame by frame.
My question about this cache files, they include substep information or no? :roll:

I know, if I cache particles in maya and retime them, I have normal motion, because parameters (Vel etc) save in cache as vectors, and with retime just interpolate.

If you save anything out to disc with velocity info, then bring them back into Houdini with a file SOP, you can then interpolate between frames by appending a cache SOP with $FF in the lookup instead of $F. Turn off integer frames in your animation globals and scrub to see the difference between $F and $FF in the cache SOP. There are also new time warpy kind of SOPs that might do the same thing.

<edit>Oh, I forgot, to retime, use a chf expression in the lookup instead of $FF and then you can retime your sim.</edit>

Not sure about DOPs though… I imagine the same principal holds true.

Sean

Thank you!