FLIP Simulation Render Setup for Beginners in Houdini and Redshift

in this video I demonstrate how to set up your scene to render out a simple flip simulation focusing mainly on how to extract different types of data from the simulation using different dot import nodes I'll discuss the difference between a bot import note and Dobb IO node and then I'll show you how to configure the top Ayano to prep the scenes render the flip tank fluid then I'll explain why we need to render the RBD object from the simulation instead of them using the original geometry node last I quickly set up some simple materials and assign it to the respective geometries the water and the teddy bear then I go over the lighting conditions and how to tweak the material so you can get the same look as I did in this animation the material setup is using the built-in redshift materials so it's nothing special since material setup is not the focus of this video don't expect much from the material setup this video mainly focuses on extracting the data from the simulation to prep it for rendering if you're wondering how to set up the flip tank sim where the teddy falls down I show that in a different video titled flip tank basics for beginners link in the description so I rendered out the teddy bear scene and this is how it looks like those of this animation has white water added to it this foam is added to it now that that wasn't covered in this video yet and I'm probably not gonna have time to cover in this video but it'll probably be the next video after this so I'm just gonna go over how to set up we have the simulation running here if you haven't we know how to set this up however in order to render this it needs to be in a geometry format or needs to be in a different format as you can see here if I put a render flag on the dock not let's put in the redshift just gonna lower I put this year Tara 1 she's gonna put on the dome light so camera 1 this is the angle it's not gonna render I mean you see the teddy bears but you don't see this flip simulation it needs to be in a different format as we know that's where the top import comes in now this the top import is the one that I've been using in the previous videos this is not what we're going to use there's actually a different one so if you're gonna adopt there's actually quite a few this one though I always the one we're going to use for the flip tank simulation to render the flip tank so top import is mostly for geometry to turn it into geometry or points or something but for this one I'm gonna use the DA pile never the dot bio again we had to specify dump network so that's this guy and is asking us for the dot note that we want to render out which would be the flip object so you can search for this in the dotnet which is in the flip sim contacts which is where we are right now and inside the dotnet so we have to look for this dotnet that's which is this one and inside there there's a flip object that's what we're trying to convert the fluid that would be this guy so I'm going to turn this render off let's go back to the geometry so we're still not getting anything now if you look carefully the presets we have to actually set what fields to bring in so if you take a look in the geometry associate there's nothing we're bringing in nothing because we haven't specified what fields to bring in so choose flip fluid there's our particles I'm gonna compress all this data so this just makes the data more compact particles foodservice this will convert it into a fluid that's what we see it was really good idea to put in the file cache because this does take a while to one to cook and then compress and then convert it into the particle fluid surface the fluid compressed not as it doesn't take as long but the particle fluid service will take a little longer end as well of course the cooking will take quite a while throw it down and then you can just cash it up now you probably noticed that there's no tiny bearers this only brings in the fluid now how do we bring in the teddy bear because I can't just like leaving this flag on doesn't do anything but that's just up there that's just the teddy bear being up there that's the stationary spot that he's at right up there that's not what I want to render because if you remember correctly in the flip simulation the teddy bears are important as RBD objects so they are part of the simulation they drop into this tank so we really don't need this play rendering the the teddy bear up here doesn't help us at all so I'm gonna turn off the render flag off this the teddy bear the initial geometry go back into the flip them now I'm gonna use my good old stop import now this is the one that I've been using in my previous videos drop in the.net here specify what it is and then import style what do I want to import I want to sorry I'm one run I want to import fetched geometry from dot Network okay but it's getting no it's getting all the particles in the teddy bear now I just want the teddy bear so let's take a look let's take a look over here for the.net what does it have it has this tree diagram it has a flip object which we've imported the flip object into this top import and then we have the ground plane which we don't need but I want to port these through the ice these three RBD objects is what I want to import grab outside extract I want to extract these data from these three RVD objects from the Dom simulation from the flip simulation I want to extract that data and bring it into this contacts so what we do it goes object mask so it's asking you what do you want to extract what objects you want turns charge RBD and the asterisk is actually wildcard so it can be anything that begins with our BD and as you can see here we have our BD object one two three so what this will do it will find everything that begins with our BD so now we have the three teddy bears extracted so we can put down a render node both of them you can actually merge this together but I wouldn't like you can just the view what it looks like if that's what you want her but I wouldn't merge it like this because you need to apply a material to this flip simulation so the material goes here or you can apply the material here so material here this would be a teddybear material you can put down for it and the material here a water material for this one it's one way to do it and then you can merge it down so I'm gonna quickly I'm just going to quickly make a water material like superfast you probably want to take more time into choosing the color and and tweak all the parameter settings you choose the right color sure you gotta go back up simulation here plastic and this one would be my water come up here if you remember correctly we have the teddy bear here this is our original teddy bear geometry let me show it to you in the 3d viewport so this teddy bear is all the way up here but I I can't render that one because this one is a static object now I want to show you if I render it out now like okay I have the render flag on our original teddy bear this is the static object that I prep the drop down the position of the drop down before it enters the simulation if I turn this off turn it on so this is he's statically in the air we're on frame 61 and he's still not within close range of the he's not falling he's not even close to the water if I go to okay let's go to this flips in let's turn let's go to the render let's render a frame that's rendering a frame 61 now let's render this here so all livers over here this is inside the simulation we're inside the flip simulation at frame 61 let me just drop down emerge just to show you so all of us supposed to be falling into the fluid right now so we can just delete this I don't need that I just want to show you the difference between rendering this Oliver and this Oliver so I want to turn off the render flag so we're only rendering this Oliver over here and I don't see him anywhere in here that's because he's still in the air over here he's not even close to the simulation over here so that's the importance of rendering between the RBD object over here this one which actually is these guys these guys are the dynamic objects they're actually doing something they're affected by the simulation this is the results of the simulation data so this is the result of the gravity affecting Oliver and Oliver falling down that's the result of it this is just your input data this is just the data we feed into the simulation telling the simulation where to begin we want Oliver to begin here this is what we feed into the simulation this is our input data so I'm going to add a new camera then I'm gonna come here and render the second camera out okay now because this teddy bear the original static teddy bear doesn't have a material on it I'm just going to really quickly make a new bits here I'm just copying that one over this one okay so this the blue one is our static original teddy bear once I turn off this flag he's no learning there so these three red teddy bears are rendering from this simulation at frame 61 frame 61 is the rendering flips sim simulation results the results of the teddy bear falling into the water so if I enable both this is the simulation data the results of the teddy bear falling in this is the blue one is our static is our input data now we have that we've done this bird here only just the illustrate that it works this is not the proper way to do this we're gonna put an object merge in here and back into this original geometry node and bring the results of the this flips and data back into this geometry node then we'll have the results so we have the input coming from this blue one we put the input data into the simulation and then we extract the results after Houdini calculates the simulation we grab the results of the simulation data and we grab it back and put it back into the geometry after assigning the material to the respective geometry you'll find that even if you render it it'll ill only render the one that you have the render flag on the problem is we have two objects now one for the water and one for the plastic so if I switch the render flag over here it'll only render the teddy and if I switch over here that will only render the water however I want to render both you could say that you could merge it this would fix it however it's it's not the best solution I'm just going to show it to you so that you see that it works now we're not going to render it like this I'm going to keep the render flag on the water this is not affected by the simulation so what can we do we can go into here and drop down an object merge so I'm going to label this Oliver sim data so well it's not really data sim I'm going to bring in the teddy bear from the simulation the one that is affected by the simulation I want the results of the teddy bear after the simulation him Oliver affected by the gravity there's Oliver so he is falling in then we put down a null here call this render so we're gonna render this one and that way it's more organized so we couldn't render the original teddybear like this original time because this one is actually static but we can put down an object merge node and bring in the results of the teddy bear affected by the simulation which is this guy so basically the object merge node is bringing in this into back into this geometry are we originally geometry node so this way it's more organized I can even put something here simulated all of our tenth so this way it's more organized we render this out now so there's our teddy bear so I had rendered this animation out so I can show it to you this is what it looks like so we have our tiny bear and we have our water so as you can see here the render that we've done looks nothing like what I showed at the beginning of the tutorial this now if these white bubbles are created with by the white water the white water will not be covered in this video however I will show you how to get this material like this water this blue water looks nothing what we have right now looks nothing like this you so erm it's our water material is not even see-through we I can't even see what Oliver looks like it right now it's a black shadow blob within the water here this is see-through I can actually make out some of the features on all of our space so let's tweak the water material so this is not our water material base properties I want to actually see Oliver when he's inside the fluid the transmitted minutes color is giving the water the blueness let's turn down the absorption scale so it's like 0.5 and see what happens okay we see a little bit more I can make out a little bit of the run it's starting to show what if I turn it to 0.1 now I can see him very clearly however the water is a bit too clear I'm going to turn this back up just a bit is there a point - I think that looks nice now let's go back it still looks different but we're getting closer now when you're rendering water you need good lighting you need HDR lighting this is the default red shift dome light that I brought in and as you can see there's no HDR lining to it now I had brought in to HDR light Maps ahead of time so I'm gonna turn this default one off so I'm gonna start the render turn this guy off so we should get darkness and we're gonna not gonna use this anymore let's start with the water this light actually let's start from scratch and I'll rebuild it from a default dome light so the lights coming from this one right now so these two are off let's switch to some 61 we have a nice frame I'm gonna use these guys these two from references here I'm gonna bring in the HDR light now you know I got this light map from HDR Haven calm even when you're rendering water you want a high contrast light map so in HDR Haven calm they have conveniently have a search criteria that you can search for high contrast HDR light maps which is very convenient now right after entering just just putting the dome map in you can see there's a huge difference between this one actually let me take it out I'm gonna take a snapshot put it back in so then we can compare so this is what it was before and after well yeah this one has a background but yes you can see the material the water looks very different a pin you can actually turn the map around you can rotate it let me illustrate this here which give you gives you a total different liner that looks pretty good and also you need a better camera angle so this angle is not the same angle I used before so let's try adjusting the camera it's starting to get there let's disable the background again it's starting to look like what I had before ok this is what I had before so this material looks it looks similar now the color is a little different and the material color for the teddy bear is a little different too it's actually this the one used on the left is a red plastic material the one on the right is a green jade material now we can do we can switch it over so the plastic I'm going to change it to Jade and I believe I had a deeper color Jade something like that now this dome light is affecting everything in the scene I actually want the light to only affect the water so how can we do that they don't select the dome light go to objects enable light mesh I'm just gonna pick the synthesis the water and we're gonna create a little in geometry the issue is here in the flip sim I merged them both together the water and the teddy bear they're merged together so I don't want that let's remove it so it's going to render flag is on the water so go back up here but then object merge Oliver render I would probably put a null after that but so let me go back to the light dome object let me disable this so this is what we had this is light affecting everything in the scene so now we can see all of her now I'm after I enable this because I just in flips it so light for this dome light is only affecting what I selected here which is the water this is because I want a different lighting condition for the water and a different one for the teddy bear let's add another dome light so now this is another redshift dome light now I have these color hex values I recorded ahead of time because I was it takes a while to play around with it until you can get the right color that you want but for filming purposes I'm just known I prepared before I'm gonna turn this up okay let's see so it still looks a little different in the render especially with the tiny baby this reflection it looks a little softer like like it's smoother now this is using the Jade material with the red shift the red shift Jade material so let's go into our wretched Rob red shift global illumination now the GI you need to choose something I was using brute force the you'll get that nice soft teddy bear look I'll demonstrate how to create the Whitewater for the scene in a different video if you check back in a couple of weeks I'll update the description with the new link when I'm done with the Whitewater video

Channel: bubblepins

Views: 9,688

Keywords: redshift, houdini, sidefx, FLIP simulation, water simulation, rendering, materials, lighting, water, tutorial, vfx, 3d vfx, beginner, 3d render

Id: kVzaNaiq03w

Length: 29min 41sec (1781 seconds)

Published: Sat Jul 27 2019