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FLIP smorganic/sheeter effect?

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I know that I posted this video in another post as an mp4.

So here is a vimeo video that shows all the stages for this simulation result!

I hope you like it!

Thank you!

Alejandro

Edited by Pazuzu
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Really nice Pazuzu! How do you create the individual droplets coming from the crown, is that a separate particle emission?

 

 

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14 minutes ago, scorpes said:

Really nice Pazuzu! How do you create the individual droplets coming from the crown, is that a separate particle emission?

 

 

Thanks for the comment!

Its part of the same simulation. That WIP shows a new option functionality of my small scale pipeline to control how much do you want the droplets to detach from the main fluid body. Its a very important artistic control in a simulation.

Cheers!

Alejandro

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Alejandro, is there any update to your Asset yet? Latest tests looked stunning for sure, but some areas could be improved still, right?

 

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1 hour ago, tylerafx said:

Alejandro, is there any update to your Asset yet? Latest tests looked stunning for sure, but some areas could be improved still, right?

 

Hi,

Yes I have some updates going on. Unfortunately I can't post them. But which areas do you think it needs to improve? It will be nice to discuss about it.

One thing that I was working on was the velocity overshooting issue, So the contractions of sheets was not behaving right in terms of rate and volume preservation, this issue is visible in the latetest test I posted in this forum topic. I fixed that already in my last iteration, I'll try to post some results soon.

Thank you!

Alejandro

Edited by Pazuzu

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@tylerafx Here is the update I was talking about. The mesh still needs to improve, but this is just to show the tool's update/fixes that I did on my pipeline to get rid of the volume issues and overshooting mainly to have a more natural sheet breaking and wobbling.

I hope you like it!

Thanks,

Alejandro 

https://www.dropbox.com/s/9io3yow61dsivld/Tension2.5_sheetColapsing_VolumePreservation_01_v002.mp4?dl=0

Edited by Pazuzu
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Now we are talking! Impressive.. definitely need the ripples to travel a tad more, yet you can see they dont affect the dynamics as much. How about air influence and bubbles/airentrapments? is that in the cards?

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6 minutes ago, tylerafx said:

Now we are talking! Impressive.. definitely need the ripples to travel a tad more, yet you can see they dont affect the dynamics as much. How about air influence and bubbles/airentrapments? is that in the cards?

Thanks!

Yes, the ripples on this mesh test are just a post process, so there is no direct relation with the sim; That's why it still needs improvements. Regards air influence I have some options already, that's why the sheets breaks also, is like when you have a cloth and because of the drag mechanic's you can affect how it will fly relative to his shape against the wind, same should happen with a fluid sheet but the influence is a bit different, but this will lead to a more natural look regards sheet breaking. Finally bubbles and trapped air, this one is more artistic driven, I did some tests some years ago with a very viscous fluid ( https://vimeo.com/69638111 ), but was just using fake rules to populate them; But that is also in my to do list, like I said the wind or environment is so important for this kind of details, for bubbles is a combination of pressure, vorticity and wind/environment interaction, or maybe I'm wrong, its all about to experiment than to find a "Physical correct" way of doing things. :)

Cheers!

Alejandro

 

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Right, and finally inner vorticity plays a role too.. eventually it will get too complex to calculate/simulate properly to make sense I guess. Yet its these finer aspects that really make a simulation stand out. And of course how the fluid reacts to collision objects, adhere and stick, repel etc.. ideally in realistic scale depening on gravity force for example...  Really looking forward. And yeah, would love to see some hip to dissect, even a ditched down version if possible.

Cheers

Tyler

Edited by tylerafx
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Hi,

Here is a personal project that uses a new iteration of my small scale pipeline. I still need to improve some things regards the micro-ripples but I think they are working well for this one.

I hope you like it!

Thanks!!

 

Edited by Pazuzu
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Mesmerizing

How many particles there are in total? Each drop looks like has around a hundreds if not a thousand of particles inside

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12 minutes ago, Andrea said:

Mesmerizing

How many particles there are in total? Each drop looks like has around a hundreds if not a thousand of particles inside

Thanks Andrea!

Attached are two screens where you can see the general particle count. I tend to not abuse the particle count to have good meshing results (so I don't use re-seeding), that's mainly because if you need to re-time you can have weird pulsing artifacts, so the only way to overcome this is to over-smooth, and that can be very expensive sometimes and will kill nice details, also boundary conditions can have flickering as well with overcrowded particle clusters closer to colliders. Instead of this I use a method to redistribute the particles to have a more uniform distribution between them, this way you can have very nice and smooth edges without so many particles and have a more clean and smooth mesh without sacrificing details. 

generalView.jpg

dropPointCount.jpg

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Thanks for the detailed answer!

I thought there were at least three times this number of particles. Yep definitely if you want to slow it down post simulation, reseeding is out of question. This sounds very interesting! 

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Hi,

Here is a new personal project that I did using my small scale fluid pipeline aka Tension v2.5.

I hope you like it!

Thanks,

Alejandro

 

 

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Awesome decision to hold a masterclass on this! Certainly looks incredible. How are the additional particles tracked, eg will there be a volume/mass conserving feature possible?

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Posted (edited)
6 hours ago, tylerafx said:

Awesome decision to hold a masterclass on this! Certainly looks incredible. How are the additional particles tracked, eg will there be a volume/mass conserving feature possible?

Thanks Tylerafx!

Regards additional particles. I always tried to not depend on hole fillers to preserve the sheeting behavior mainly because its a nightmare for everything, volume gain, mesh flickering, etc. But at the end I also implemented a way to inject particles that doesn't affect the behavior nor the meshing, it was a bit of a nightmare to tackle all this problems but at the end works pretty well. The only one that I'm still working on is the volume gain, but at very high speed sims, its a nightmare!! 

whithout_fillerMask_side.mp4

In this preview extracted from my last work, you can see that the point count is constant, so no dynamic particle injection or how I call it fillerMask :) But you can see how the sheets are preserved without any dynamic particle creation to sort of protect the shapes, or to have a good looking result. Also there is already some volume/mass preservation, the uniform distribution that is driven by a freeSurface mask maintain the particles from collapsing or to be extremely apart, so all the particles are flowing in a very smooth harmony, and this is key for a good meshing without using an extreme particle count.

fillerMask_side.mp4

This is the same version as above but here I'm now using my fillerMask technique. But you can see that even with this on, the sheets looks almost the same as the above preview, so in conclusion this should be used only when you have a very fast simulation and you don't want to use so many substeps to converge to a nice solution, or if some client needs a pretty big and soap like sheet.

fillerMask_metrallia.mp4

Talking about extreme cases for a filleMask use, is this example. Here in this preview you can see how the particles are created when the distribution begins to fail because of the very fast expansion, of course this is retimed, but you can see that even with fillerMask on, the sheets are still collapsing naturally so the volume gain its greatly reduced (I'm still working on to have way less volume gain). Another very important aspect when you use the fillerMask or in other cases Reseeding and you need to retime your points, both techniques can lead to weird pulses and jittering on your points and you will end up with a weird looking mesh. The solution I gave to this was to save out my simulation data directly inside the solver at the last substep stage, this ensure that I can have that substep data to have a more precise retime of my points. For this I implemented a point retimer with substep support (the default one only uses integer frames for the interpolation).

 

I hope this make things more clear. (sorry about the video compression, its hard when you have tiny points)

Thank you!

Alejandro

 

 

 

Edited by Pazuzu
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Amazing! 
Can you shed some light on how you generate the free surface mask? Are you using SVD? 
regarding the tendrils, what kind of controls do you have? Is it mostly to control the number of tendrils or can you somehow also control manually where they will happen?

Thanks! 

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11 minutes ago, WhyGee said:

Amazing! 
Can you shed some light on how you generate the free surface mask? Are you using SVD? 
regarding the tendrils, what kind of controls do you have? Is it mostly to control the number of tendrils or can you somehow also control manually where they will happen?

Thanks! 

Thanks WhyGee,

Regards freeSurface mask you have many options, you can use the curvature, density or even an edge detection technique to separate the borders.

Regards sculpting controls, because is Houdini, is all about to use velocity fields for that, I think is the best way, forcing this kind of things internally will compromise the behavior, and its very important to not constraint that to reach more realism on the simulation.

cheers!

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1 hour ago, Pazuzu said:

Thanks WhyGee,

Regards freeSurface mask you have many options, you can use the curvature, density or even an edge detection technique to separate the borders.

Regards sculpting controls, because is Houdini, is all about to use velocity fields for that, I think is the best way, forcing this kind of things internally will compromise the behavior, and its very important to not constraint that to reach more realism on the simulation.

cheers!

Thanks for the reply!

Not sure I understand. Isn't the free surface mask, all the particles on the liquid/air interface?

Are you modifying field vel or particle v to achieve these results?

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