Hi everyone,

I have two flip objects in my dopnet, and I have a Pop Advect By Volume for advecting one of my flip object. But I don't know how to affect just one of them, and if I run the simulation the flip that I don't want to be advected is much slower than without the Pop Advect…

So I can I only affect one flip object in this kind of setup ? I tried with the Pop Group but I'm not able to use it correctly.

Thanks !

It seems that my simulation is veeeeery slow when using multiple flip object inside one solver… Is it normal ? When I plug only one object it's pretty fast.

popadvectbyvolumes requires volume just like pyro or any SDF or VDB. You have to feed one of those.
And using multiple object is not slow. it's just container to hold data which we can fetch at sop level for surfacing and rendering.

Hi,

I did this setup only for showing you how it was on my other computer, it's actually working with the wave tank setup (and the popadvectbyvolumes is affecting my tank, which is flipobject_02 here).

You're right, it shouldn't be slow with two objects, and I think that it's coming from my cpu… When I render a simulation, it takes around 5 minutes to compute one frame, and then 10min, it keeps increasing and at frame 20 it was around 1h30 the frame… But, at the beginning, my cpu was at 100%, end at frame 20 it was at 2%… Which is not normal at all (and I need to precise that my sim is just about making a pre-roll of my tank, so it shouldn't increase like this)

It started a render yesterday, of only one image, the samples were pretty high (but it's only one image so let's get crazy), but it's still rendering… But the cpu is at 100%.

I have this message on the Houdini console (it's still rendering my frame), it's seems that it has to do with the ram. I showed it to my stepfather (he is an engineer), and he just told me that the “0xFFFF…” was MAYBE not normal. I'm not an expert at all, and I feel a bit silly with this kind of thing… But maybe it's normal, my samples are high.

Thanks for your answer PradeepBarua !

Pretty sure that I have the same problem, except that I only have 16gbs :
http://forums.odforce.net/topic/17364-pbr-a-lot-of-displacement-ram-completely-filled-up/ [forums.odforce.net]
My scene is not optimize for rendering with big amount of displacement, so I might think about it…

You shouldn't be using two flip objects. You should merge the two sources together in sops and use sop groups before plugging it into flip. You can then use the geometry group you want in the pop advect by volumes.

Oh that makes sense !
Thank you Ian.

Is there a way to cache my displacement on disk instead off caching it on my ram during the render ?