FLIP Simulation Infinite Water Flow like Rivers in Houdini
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- เผยแพร่เมื่อ 27 ก.ค. 2019
- You can simulate rivers using a FLIP Tank setup in Houdini. FLIP tanks can be used to simulate fluids that is confined inside a container with limited supply of water but what most people don't know is FLIP tanks can also be used to simulate infinite water flow! The best example is a river that occupies a limited space but has infinite water flow.
Download Houdini Project File:
bubblepins.com/blog/water-sim...
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#houdini
#sidefx
#physicalsimulation
GREAT material, congratulations and thanks a lot, elegant and simple.
Thanks. Your explanation is very clear and concise.
All her lessons are high quality free lesson. Thank you so much!!
Thanks for the awesome comment!
Awesome,Thanks for the bunch of stuff explaining in simple way.
Thanks for the comment!
Thanks for this!!
You are genius! Your tutorials always help me so much
Thanks!
THIS TUTORIAL SAVED ME. i love you
Thanks!
Thank you so much! Very clearly put. Appreciate the help :)
Thanks for watching!
A smart way, THANKS !!
thanks for share your knowledge , nice tutorial
nice ty! Great stuff!
Thanks!
Thank you so much
Thanks for watching!
Thanks sis!
THanks for watching!
I'm in love with your voice
Thanks!
I am following all your tutorials and they are all great with clearty . I have suggested this channel to all my friends, and your voice is very beautiful.
What programming languages you know ?
I know quite a few. I am a coder trying to transition to an artist role. I know C#, c/c++ (from some arduino projects), python (because I wanted to learn OpenCV), & Javascript (because I wanted to learn NodeJS). I think that's about it. AFter you learn c/c++, I think all other languages will seem a lot simplier. Because other languages usually have memory management taken care for you, except c/c++, that you always have to manage yourself and frankly I think it's a pain! Especially when you're trying to code an algorithm or something super complex.
Amazing tutorial thanks! Do you have any suggestions on how to make this river flow loop?
Someone actually asked this before, but I'm not sure how or even if it's possible. I can only brainstorm that you would want a looping vector field to guide the water to move in a loop, but even then it doesn't really guarantee that the water would end up looping because of the complexity that goes on in a flip fluid sim. The collisions and waterline... it's hard to say. But I've never been able to do it myself. Thinking about this some more, maybe if you render your water sim from Houdini then pop it into a VFX software and make it loop in the post processing stage, that may work.
Hope that helps!
@@bubblepins thank you so much for the response :) looping vector field is a good shout! I've been thinking about using Oceans as they have a loop/whitewater function built in, is there a way to use input geo/vdb to shape the ocean?
@@arthr6818 I'm glad you asked! I actually made a video on that before. It's not exactly using a vdb to shape the ocean and instead it uses the flip tank and ocean to combine both powers to create a large ocean of water that will collide with other objects like if you had a boat or whale that's splashing water up.
Hey! Great tutorial! I was wondering if it would be possible to make this a narrow band simulation, since I only need to render the surface of the water. If it is possible, how would you go about doing it?
Oh I have a narrow band FLIP tutorial:
th-cam.com/video/k0P111aWW80/w-d-xo.html
You may want to skip to the middle, because the tutorial was aimed for beginners so there's a lot of stuff in the middle that you probably already know.
See if that is what you're looking for!
@@bubblepins Thanks! It took a bit of messing around with at first, but I got it working eventually!
Hello, great tutorial, thanks and congratulations.
Please, can you specify the size of the scene and your PC config?
Thanks a lot! Your channel is great.
The water was cooked at the size of 50x20x3 using 0.1 particle separation for the tutorial video (I think for the screenshot in the thumbnail it was lower, but I can't remember the exact value probably 0.01 for the thumbnail)
I have a i7-5820 (6 cores at 64gb of ram), buying this was probably not the best choice, because soon later AMD came out with 1950x & 2990x threadrippers. The 1950x has 16 cores at $700, which works out to be so much more value per core than my current CPU. And if you have a load of cash, get the 2990x, it has 32 cores but ranges at $2k.
Check out this video where this person demonstrates RBD sim using 1950x (16-core) it's like real time playback when you're cooking. (makes me jealous)
th-cam.com/video/FeYk6BILkoU/w-d-xo.html
@@bubblepins Thanks!
Mine is a i7-8700, 32G RAM, RTX 2080, 1T SSD.
Maybe i cant run the water sim at this size of 50x20, anyways... thanks for your time and recommendations.
Can you put a detail master class on fluids and how to do shading and rendering 😊🙌
Sorry the flip fluid scenes are getting way too heavy on my machine. I'm planning to upgrade my computer soon, waiting for a sale. I'll definitely make another fluid vid after I upgrade!
@@bubblepins we will wait for and can tell me how connnect with you
@@Mayank_think_so Thanks for the patience!
Hi thanks for the tut! Have been playing with flip for a week and trying how to optimize the water or water droplets to not show as too "blocky", eg. 14-18s of your video, on the lower right of your video. Was wondering if you have any idea how to further optimise that?
The scene at 14 to 18s mark in this video was super hard to generate with my current workstation (I desperately need an upgrade). I cooked it under 0.1 particle separation and the simulation resulted in very chunky results, I think this is similar to what you are currently experiencing. However I could not stand cooking it any better because it took forever. So to compensate for that, I tweaked around with the particlefluidsurface A LOT. But it was still kept at 0.1 particles separation, which only worked out in my case because my river is 50m long (50 Houdini units). So it doesn't look as chunky.
Usually you need something like 0.01 particles separation or 0.001 particle separation for cooking and generating the particlefluidsurface for best results, but for those (like me) with a mediocre workstation setup, but it takes forever to cook on my system.
Try playing around with the "droplet scale" on the particlefluidsurface node after cooking it. Because the particlefluidsurface node is a lot faster than recooking the entire sim making it easier to tweak and observe the feedback. Beware not to change the "influence scale" too much, because if the influence scale is too high or low it results in making other parameters less effective or results in holes all over your fluid.
And after your comment I went back to look at the original HIP file I uploaded, I forgot to filter out the "flipobject" in the "dopimport1" node in "Object mask" parameter.
I hope this helps.
@@bubblepins thanks, one thing houdini never tells user is the amount of time and hdd used :( I have migrated over from Realflow and it gives an accurate number of particles which then relates to how refined the water would be during rendering. But houdini, I have on few occasions on the verge of giving up this piece of procedural software! lol. Thanks bubble pins and keep up the good work!
@@jonmaster2143 Don't give up on Houdini! But I have seen very awesome Realflow renders look like, so I get it. Houdini can be very awesome, but its so customizable which makes it frustrating. I plan to make more tutorial videos on flip fluid in the near future, but after I upgrade my system. FLIP fluids in Houdini is very CPU intensive for cooking sims. I'm hoping to catch a good deal this Black Friday. Check me out in a couple of months and maybe I can convince you give Houdini another chance.
@@bubblepins I did noticed that GPU cooking in houdini is not in anyway faster than cpu eg realflow you can see quite a difference in speed, I would attribute down to the endless knobs within houdini that slows things down dramatically. But saying that houdini is possibly the only package that offers most 3rd party plugins within its core software, without having to invest extra for 3rd party plugins. O well, back to drawing board for me in the meantime. If you need help in workstation configuration, give me a buzz, am sure to be able to help.
@@jonmaster2143 Yeah I love the flexibility of the plugins and digital assets and all that stuff. The parametering in Houdini will definitely frustrate anyone when things don't do what you think it does and you got all these knobs to try one at a time. Oh that reminds me, have you tried the Shelf Tool? It's a one click solution, well sometimes requires a few more clicks, but the scenes generate with decent already tweaked parameters, however you get what is preprogrammed so if u want the scene to be something else then its back to square one lol.
I'll definitely take you up on your offer for advice. Right now I got my eyes set on AMD's threadripper, but I'm low on budget so I was waiting for AMD to release their 3rd gen on Nov 25 and hope that the 1st gen chips go on sale LOL. But I bet I will regret that next year when I want to upgrade because AMD changed the motherboard for the new threadrippers.
I believe Houdini only uses the GPU to load the geometry onto the 3dviewport using opengl, but I do remember hearing about SideFX planning to develop an engine to use the GPU for cooking simulations. But who knows, I find that some of the nodes in Houdini are still single threaded which just adds to my pain when cooking FLIP fluids.
I really liked your previous two FLIP fluid tutorials but this one could have benefited from an included scene file. Quite a bit of the setup was skimmed over in this one. I followed as far as I could but Houdini entered infinite cook mode when attaching the FLIP object in the Dopnet so I knew something in my setup was misconfigured. Regardless, many interesting bits of knowledge in here; I just couldn't complete it.
Thanks for the feedback. I'm still working on my style of teaching. May I ask which part did you have trouble with?
@@bubblepins Sorry for the delay in replying (work got in the way of learning :) I can't really pinpoint exactly what went wrong but the main problem was that I had no finished reference to compare my project. A scene file isn't necessary if every step and node and setting is covered but I sometimes had no idea if I named things correctly to match what you did. I didn't know if I was supposed to select the polygonal version or the VDB version, etc. Things like that. At some point, I connected the flipobject to the flipsolver in the DOP network and it just went into a never-ending cook so I had to force quit Houdini. I know everybody has different preferences for the way tutorials are done but I generally like to follow along and build it along with the instructor. If steps are skipped, which is understandable, it's just nice to have a finished, working scene file so we can cross reference with our own and see where we went off the rails. I appreciate the effort of anybody who takes the time to make tutorials (especially free ones!) so I don't want to look a gift horse in the mouth :) Your tutorials are appreciated and I usually don't get derailed with them.
@@vger2 Thanks for the reply! I have recently started adding project files to most of my recent videos. But this FLIP video was filmed when I just started out making videos, so I hadn't started uploading the files back then. I will try to find the original project file for this video and upload it in the next few days. I agree sometimes its the tiniest things in Houdini that just makes a huge difference. Thanks for watching! But just a small reminder, all project files I upload don't include Redshift materials, because it goes against the user agreement to share those. So I delete all the materials before uploading the scene file.
@@bubblepins I look forward to more FLIP videos. It's a difficult corner of Houdini to master because it can quickly grind even a powerful machine to a crawl and it's difficult to balance settings until you try something, wait overnight for a render and throw your hands in the air and shrug when THAT failed. Rinse. Repeat. :)
@@vger2 I totally relate to that. I have a mediocre CPU and the FLIP sims take so long to calculate. I found the previous HIP file for this video, but I deleted all the cache so I need to rebuild it all to double check if it's still working, sorry for taking so long. I have been thinking of getting a new CPU for FLIP sims, but maybe later when I save up a bit more. Lately I've been drooling over AMD's Threadrippers. I saw this video where someone did a sim in realtime a collision scene for test with like hundreds of pig heads with AMD 1950, it was like realtime playback! Imagine what we can do with FLIP sims! I'll try to think of some new FLIP sim tutorial ideas that I can do. I am thinking of a new idea for my next video, making a city and then flooding it and have the FLIP fluid interact with RBD destruction. That might be interesting, but not sure if my CPU can handle it.
Hi, is there a reason why my static objects are not working? The water keeps falling out of the object (in my case it's a bottle). Like the water is just falling down wards. Many thanks!
Does the bottle have enough thickness? And have you tried adding a proxy volume to the static object. Sometimes to improve the accuracy, you need to convert the static object into a vdb and plug that vdb into the proxy volume parameter near the bottom of the list of parameters for the static object node.
Hope that helps!
How can we collide river with water fall?
Can we use 2 flip solver and do it because water fall need different setup from river?
I believe you only need one flip solver for that. Put a flip fluid emitter at the top of the water fall, that should pump out the water for the water fall. And just have a body of water at the bottom. It should do the trick, you can use closed boundaries to make sure the water river always has fluid.
Hope that helps!
I have a near-identical setup but river is not maintaining its shape. I've plugged in the river water geometry to be the surface volume but the water continues to flow out so my river loses water. My boundary layers are acting correctly and reseeding particles in the direction I've specified. Any idea what could be wrong?
hmmm maybe just shooting ideas out. Maybe you have a hole where the water is flowing out of the terrain. Double check the water geometry after doing the boolean subtract and make sure there's no hole. Or just simply do a small test and lift up the initial water geometry and just let it drop down for a few frames and see if it still leaks water.
I hope that helps!
Double check the waterline and see if it is at the correct level, this will refill the flip object according to the waterline level. 9:34
Hope that helps!
Thanks. But how reverse direction flow?
Reverse direction? Are you referring to the water velocity direction emitting from the boundaries? You can control emission and sucking direction of the water at the boundary by controlling the boundary velocity. If you want to suck water on all sides of the boundary, which I assume is what your question is trying ask, I think that can be more easily done with the newer FLIP SOP tools in Houdini 19. I haven't created new tutorials on the newer FLIP sop tools yet. It's still in the works. But SideFX added a lot of newer features in the FLIP sop tools.
I hope this helps!
Why are most tutorials for Houdini made by girls? Don't get me wrong I ain't complaining. Well done on the tutorial it's gonna come in useful on my next project cause Blenders water sim sucks! Btw you've got a really smooth voice