Houdini Flip Fluids Introduction Part01

[Music] hey everyone this is amin from cg artist academy and i'm back with a new tutorial this time we're gonna learn how to create a flip solver or flip simulation solver in houdini okay so this way you can create your basic fluid sims like creating a viscous fluid like a chocolate or caramel or honey or something like that so it's a basic setup and that way you can learn how to create these things very easily in houdini so it's an introduction so let's get started so here we are in houdini first of all we need to create a jio node okay and let's rename it to emitter okay now copy it and like paste one time here and one more time paste so there are three things we are going to create actually we need only two things this is emitter and this is will be my collision geometry so collision geo okay and uh first of all we need to create a meter so what we gonna create is we will create a sphere okay and it should be a polygon sphere okay now create a transform node so that we can change its uh values some few values okay so in uniform scale 0.3 or maybe 2 is fine okay uh enable this option you can see after the transformation okay so 0.2 is the value and one more thing we need to do is in sphere let's frequency to be 4 okay now we need to create a flip source so let's create that connect this and let's see so we are seeing those voxels so we need to get more dense voxels so we will change the vocal size so it would be around 0.02 i guess yeah so now it's looking like a sphere and one more thing we need to add is a null so it's filled with it will be the controller so name it emitter out okay and one more thing we'll we need to change is uh it's translate value in y-axis so let's make it around sorry in translate three so yeah emitter should be this high uh okay that's it for the emitter enable this option and let's go back and now we need to create a collision geometry so um you can add any geometry you want to collide with like if you add a file node you can select whatever the geometry or whatever the model you want to collide with okay in my case i'll be using the houdini pig head so let's add this okay now this is added now create a transform node again and and this now value should be around 0.8 i guess yeah so this is looking better and one more thing we need to do is we need to like translate it in count one yeah that's looking good and then go to diameter and let's translate it like 3.5 yeah and i guess in comparison with the big head it's looking still big so let's 0.215 yeah that's better now go to their collision geo and what else we need to do is we need to create out i mean null so let's rename it collusion out okay so that's it for the collision and now we need to create is the dominate so let's create a droplet and rename it to flip sim now dive inside it and here we need to create few elements so let's press tab add a flip object flip solver okay and i need a volume source volume source okay so yeah first connect these flip source to the first input and volume flip object to the uh first input and volume source to the last one okay and connect this to out here we need to change few things first of all we are seeing this spheres we need to convert into uh particles so to do that go to your flip object guides and here we see the particles and instead of sprites or spheres we will choose particles so that's been done now it's getting its own path so let's delete that we don't need that so it's gone what we need is we need here particle source should be here so go to your volume and here instead of source smoke we need to change it to source flip and here we need to select the path for the emitter so let's add it now emitter has been added to it and let's see it's okay nothing is happening so let's figure out what why this is happening so it's happening because we don't have any gravity in our scene so let's create that gravity add this in here and let's again see yes now our particles are coming out okay so but this time they are not colliding with it so what we can do for that is let's create a static object so tab and static we need a static object we need a static solver also let's connect these so connect here and merge here here and merge connect to the output and press l to layout this here we need to uh add our collision geometry so here it is okay it's here let's add this so we can have this here now off this option and disable this to display geometry we don't need need that okay and let's see how the simulation comes down and you can see it's colliding now so it's pretty good but the particles are like very less so we need to increase the particle separation to increase the particles so go to your flip object and here we can see the particle separation so let's create it around 0 3 i guess it's completely uh depends on you guys how dense or how uh much more particles you want it's depends on your system also because it has has to be handled so just play around this don't go too too far okay so let's see again what's coming and still after putting this it's not getting the way i want it's still less particles so we need to fix that it's happening because in a flip source in here if you see in the emitter emitter so here we also have a particle separation so if i change this to 0 2 now we will get the correct amount of particles but we don't have to change it every time on the both things in flip source and the flip object so we need to do something here okay so let's go to the flip simulation and flip object let's copy it and copy this parameter now go back again to your emitter and flip source and here we will right click and paste the relative difference so now what it does is if i change the value over here in this flip object particle separation the value will automatic automatically change over there also so let's try 0.02 now let's see again here and you can see this value is changing so it's done here now and again see how it comes so my simulation is getting pretty good here okay one more thing we have to do is with the collision geometry okay by default it's getting as it is the geometry what else we can do is as per uh many theories okay if you convert it into a vdp the simulation gets faster so we can definitely try that so let's do that type vdp from polygons okay so let's connect here and see this and here we need to change its voxel size so maybe around 0.0 sorry 0.02 yeah it's looking like it's looking nice and now over here in flipsim okay what we need is let's off this option okay here in static object go to your collision and enable this collision guide okay so if you see here in the mode we need to change it to volume samples so now you can see that it's better and more accurate collision geometry okay so i guess we should use this only and let's again see how it comes so the simulation is done and i can say that yeah it's looking much better okay because of the increasing of particles and the better collision geometry okay so uh so far i guess it's very simple and easy to set up all these things okay so next we need to do is my 3d container is way more big than the area of simulation so we need to fix that we need to change that because we don't need this much this uh this much big container so what so change that what we can do is select this flip solver and press enter sorry select this flip solver and in here 3d viewport uh place the mouse over here and enter now you can see we can get the controller to change this its dimensions okay so let's scale it and we can do that by like select here and press shift so it will scale the both ways okay and make sure you are at the first frame i am not okay and again in z-axis place your moisture mouse over here and press shift and again scale it okay same goes with the y and scale it okay so let me quickly change the scale of it okay so i did that changed it and yeah this much is better uh one more one more time i need to do change this okay it's completely uh depends on your simulation and the thing you want to like generate so feel free to do accordingly so i guess it's done correct so let's again simulate this and don't forget to save your file so the simulation is done and yeah it's looking better and faster so next thing is like the fluid is very uh watery okay okay it doesn't have any i can't say any viscosity but not like the way i want uh like a caramel or chocolate or something like that okay so do that so to introduce the viscosity we need to change the parameter and which is if you go to your flip solver okay and go to your uh wait yeah go to your volume motion here you will find the tab called viscosity just enable it and viscosity by attribute okay that's it and now go to your flip object and here you will find the tab called physical and here you can introduce the viscosity how much you want so if you don't enable that this viscosity won't work okay so let's change it to around 500 i guess and let's emulate again so you can see that the simulation is done and the fluid is very viscous now so yeah it's looking better yeah it's looking like a um you can say uh thick honey or caramel something like that okay so yeah that's how you can introduce the viscosity and change the parameters and it's completely depends on you how how much viscosity you want in your thing okay so yeah that's a pretty basic and that's how you can create your flip simulation very quickly in houdini and i hope guys the steps are not complicated it's i tried to make it very easy to create us this setup very easily and create these effects okay so i hope you like this tutorial very much if you like it please like and subscribe my channel and share with your colleagues okay and don't forget to press that bell icon so that you can get the updates as soon as possible as soon as i upload the videos and in the next tutorial i will tell you i will show you how to like match the fluids in houdini and export to use in any dcc application okay and so see you next time thank you you

Channel: CG Artist Academy

Views: 18,121

Rating: 4.8859649 out of 5

Keywords: education, cgi, 3d, vfx, food, particles, fluids, work, knowledge

Id: M1zVMTOCHp8

Length: 16min 37sec (997 seconds)

Published: Fri Aug 07 2020