Beginner Houdini Vellum Tutorial - Rainbow Grains (Free Scene File) AUDIO FIXED

hey it's bloomin glare today we're gonna be covering how to create a large simulation with around a million particles using the new velum solver and it should be a pretty easy one but I'll I'll go ahead and show the end result so okay so there's a lot of geometry that's being used but it's very similar to set this up so let's just hop into Houdini by default I always save the file when I begin just so there's a backup that's created just in case things crash which they inevitably will I've made this before so I'm just gonna go her oh go ahead and overwrite it and the first thing we'll make is the the actual collider geometry so we're gonna drop a tube dive into the node and then convert it to a polygon I want this to be you know a relatively high fidelity so let's bring this to 60 for the height I'm just going to make it maybe 0.15 okay so nothing too deep some of the references that I'm using for this tutorial are are just some high-end cosmetic photography so these are some of the I guess this is some of the materiality that I'm using as as a reference especially these types of things the granules which is pretty easy to achieve with vellum so we'll be looking to make a container that's similar to that and one of the things you have to make sure to check is endcaps okay and by default that's just gonna add you know two caps to your geometry then we're going to delete one of those so just hit select select the top hit delete on the keyboard and a bar default when you do that Houdini automatically creates a blast note for you and that's just storing that deletion from the source geometry okay so what we want to drop now is is a note to add some thickness to this and for that you can use a poly stirred okay just enable that and let's just try and give it some distance here and the extrusion nothing too crazy maybe 0.12 even point one is fine okay so you might be wondering you know why you have this this purple or blue coloration inside here and it's because this isn't actually closed geometry you can see if i zoom in you can see the cap here and this coloration is basically showing you that you're looking at an inverse normal so this is the interior of the geometry so we need to close that off and there's a handy little dialog box here called output back that will close it for you okay there you go and you've got a beautiful ashtray all right we just want to round off those edges just so we get a little bit nicer play with the particles and for that we'll use the poly methyl okay and again this is just really basic kind of modeling I'm definitely more comfortable modeling and other 3d software Suites but you know they should do so with the poly level node enabled go to fix distance and just give it you know just a tiny bit maybe once a five and by default you can see we're getting these weird kind of pinches in the geometry and to get rid of that just disable a lot of vertex splits you can add as many divisions as you want I think even one is fine for this tutorial and then there are a couple of options here for the Philip shape so you can go solid and go crease and you can see these a bit better shann fur you'll be able to tell a little bit more what's going on if I increase the fixed distance so round is gonna give you a rounded shape which I prefer you can go sham fur which will just kind of give you this nice angle here and you get the same angle in here here crease it's a bit weird solid there weird as well okay so I would if it were me I would choose between these two I'm gonna go around and we'll just unable the grid so I can see where I'm at here okay and that's essentially it for the collider so we'll drop a null and let's just call this a lighter out enable and oops call that Collider okay so this is what our grains are going to be colliding with now we need to make the source for the grains and how do we do that well it's very simple we'll draw a circle okay and by default it it defaults at the XY coordinate plane and we're just going to change that to Zed X or Z X and let's raise this to point one okay just so we can see what's going on here maybe a point zero seven five just so this geometry comes a little bit over the top of our Collider then we're going to drop the same notes so a poly extrude we're gonna output the back and for distance really low number maybe point 4.04 sorry okay and you just want to make sure that that's not colliding with this geometry otherwise your particles aren't going to be trapped inside here so we can just go to okay I think it looks okay yeah we've got a lot of space so maybe maybe let's just extrude this a little bit more maybe point zero six maybe even more actually point one okay so you can see there's still a fair amount of distance here and this will drop down eventually anyway I'm gonna increase this one more time okay that looks good and we'll raise this up once again to 0.1 okay and I'm just gonna change the shading mode to your smooth shaded it's alright smooth wire shaded and add another poly bevel just to give it a nice rounded kind of you know packed sand look usually sin doesn't have you know 90-degree angles here so it's just bubble that tiny bit maybe point zero one okay and again we'll disable vertex splitting okay and that looks alright to me might drop down a smooth node actually we can get rid of that that's fine okay and we'll make another null and we'll just call this rainbow particles [Music] enable that and we'll hop back out okay so we have the source for our greens we have our Collider now all we have to setup is the simulation and since this is a beginner tutorial you can set up velum yourself but again this is for a beginner so we'll just navigate to the shelf tools and use vellum grains make sure you have and we'll name this sorry [Music] rainbow particles okay and with that selected make sure you see these yellow line or the yellow outline just hit them greens and you'll get a few notes that are created one is called grains vellum the other an auto doc Network this is where the simulation is taking place and you can tell we don't actually have any grains right now so nothing is showing up once we've added that this rainbow of particles node as a source and the reason for that is the particles are actually too large so we're need we're going to need to dive back into where we created this geometry and by default when we chose vellum grains in on the Shelf a few nodes are created this is the one that you want to dive into this these are the grain constraints themselves and so you can see by default it's creating grains from a volume which is our source geometry and the default grain size is 0.1 this is not small enough in order to view so the geometry is basically too small to pack these in so we need to enable that and we'll just change this to points so we'll drop by a factor of 10 now you can see our grains are created okay and we have quite a few of them but they're stacked very regularly so we can add a little bit of organic packing to that by jittering the scale by enabling this it'll take just a moment okay I might pause this and then we'll come back okay so a great size of point zero two seems to work pretty quickly for me I think the the jitter scales a little strong though so I'm just going to lower it to 0.75 okay and I think that's gonna work better I mean we're still getting an organic result okay that looks pretty good okay so I'm gonna keep it at this scale but obviously you should you know create particles at at the grain size that you think kind of aesthetically looks good for you I mean this looks more like you know I mean I I realize that the particle size is a little too large but for the purposes of the tutorial I'll probably leave as is unless I'm on you know pausing a lot and then Reese emulator we're just going to hit the middle mouse button and see how many particles were actually working with so we have fifty-three thousand five hundred and two points so again you can the smaller you make this the higher the number of points you're gonna have and it's entirely up to you how long or certainly how how many you want to create just keep in mind the the the greater the number of points you have the longer your simulation time is going to take so let's dive back out here and I'm gonna turn off the velum grains node I'm going to enable the dot Network and we're just going to dive in here and see what we're working with so this is our source or velum source and you can see it's being activated on frame one it's only emitting once so these these particles are are going to be engaged only once so if you go continuous every frame the same number so 53,500 into whatever it was is going to be simulated every single frame obviously that's going to take your your simulation time it's entirely up to you how much you want to admit from I mean if you have a grid that these these points are being committed from and you know you're creating rain or something like that then you're gonna want continuous emission but for for what we're after just only once is fine okay this is the velum solver and by default when using vellum greens the substeps number is increased five I would recommend going above that if you want a smooth simulation without a lot of jittering I'm going to go ahead and put it to seven but even a number of ten or above is you know it might be needed depending on on your simulation so we have our grain source we have our Collider but we haven't set up the collider yet so the the collider needs to be set up separately and you can do that inside the auto doc Network or you can just navigate back out here select the collider and name it a surface Collider here in the velum shelf tools okay so hop back into the auto top network and you'll see there's a little bit of a mess here hit L on the keyboard and what's been created is a static object collider so this is the the path of the collider which is referencing this geometry a static solver a merge node and the rest of the information that we we previously set up so I'm gonna go ahead and hit simulate and we'll see what we're working with okay so as you can see the result is pretty pathetic it's just going to basically fall and drop not much is gonna happen so that's just preview that and but you can see that the particles are actually interacting with one another which is kind of the hardest part okay getting a little bit of play there alright so the next step would be to animate this Collider so that we can get these bouncing around and interacting with each other in a more dynamic way the easiest way to do that and I've explained this in a previous tutorial but I'll go ahead and explain it to get again is to animate our collider geometry from the outside here so instead of diving in and creating a transform node it's actually a lot faster for the solver to calculate if we come in here and let's just create a simple expression using sine so notice type of sine [Music] dollar F times let's get a low frequency value maybe six and we'll multiply that again by fifteen okay and we'll see what we're working with here so I'm going to turn off the simulation and just hit play okay so we've got the collider walking back and forth if you want a few more degrees you can add maybe a twenty five you want it to be a bit more extreme that might be okay I'm just gonna extend this timeline a bit maybe 120 okay there we go we get a nice smooth animation all right now you can add additional expressions if you like one that I'd like to use often is just every frame so dollar app Plus maybe eight so this is just rotating I believe eight degrees I think it's degrees every every frame maybe not maybe it's a radiance but okay and then we got a nice let's just make that six maybe it'll repeat that looks a bit smoother at six let's try four I like six better okay so the glider is rotating and then it's kind of rocking back and forth which is pretty much the the the same scenario that I had set up in in the reference video okay so I think that's all right now by default in the collider settings here under static object we have used a forming geometry tipped so you want to make sure that that stays enabled otherwise it won't take into account the animation that we just set up again you can keyframe an animation if you prefer and that's probably what you'll end up doing if you're making you know this is just for simplicity sake I mean you can you can easily manually enter in values and keyframe them using the timeline here but since it's really fast and easy and you get a fluid motion I'm I'm just going to stick to using this expression and dive back into the auto dotnet work okay and I'll pause again and simulate and we'll see what we're working with okay so everything is simulated we're ready to preview let's go and the result is okay but there's a few things that I like to change just to get more organic movement one is it's almost as though we're creating a you know a low-resolution flip simulation so this is kind of behaving a little bit like a liquid how it's pouring off the side the particles aren't really clumping together there's not enough friction and I think overall the the movement is it's a little too fast and it doesn't really look high-end enough so we're gonna make some of those very basic changes most of them can be found in the vellum so over here I will need to simulate it again but that's not really much you know it's not really a big deal so I'll show you some of the parameter changes that will enable this to look a little bit better number one so we're just gonna I guess navigate back to frame 1 and the first one is I'm gonna change the time scale to 0.25 actually maybe 0.333 so we'll be operating now at 1/3 speed and I think that'll just make you know it'll make it a lot of difference in terms of the quality of the simulation and and you know give it a more editorial kind of look once once simulated and once rendered out another thing that we want to do is to just increase the the friction a little bit so I'm gonna dial up the dynamic scale here to point to you okay and if you want to add clumping with these particles a really fast way to do it is to go into the Advanced tab in your solver and come down to brain collisions and by default the repulsion is at ten thousand we just want to lower this to maybe let's say how about 600 try that and everything else we can leave leave as defaulted I think that'll be okay and the default thickness of these particles should typically be the same as what we've we've what we've determined the grain size should be that way we don't get any kind of odd particle collisions so we can actually linked this number with the grain size and that tends to work out great for the inter particle collision that'll be going on during the simulation and I'll illustrate that in a minute okay and the last thing i want to do is just above the merge node i want to create a delete node okay [Music] yeah I think I delete now oops [Music] sorry a pop kill note now we're going to instead of creating a vex expression or rules for this we're just going to be going by bounding and we're going to enable a bounding box and what we want to do is kill a lot of the particles that are going to still be simulating down around here so if you're not going to kill these you know it'll still take into account that they're going to be colliding you know dropping and this is just an easier way to have you know a little bit of it's a it's a time-saving maneuver so we are going to take this and by hitting the middle mouse button and just scrolling to the left we're going to pull this down until it reaches maybe negative two and for size we'll go maybe eight a little bit too big maybe six by six so let's just zoom out here so this should cover you know a wide wide enough area to kill all the particles that are going to drop out of sight once we we set up our camera so let's just set up a camera quickly we'll bring this up so that we can see what's going on a little better during the simulation doesn't have to be perfect usually I just try to aligned align the middle of the grid to this area just by eye and then come in and change it after the fact so we'll come down here create a new camera and then let's tie view to camera so you can see this little lock pops up and now we can navigate around and it's a sh moving our camera around if you don't do that what will happen is when you try to change the view you're automatically popped up of your cameras for you so to come back in you can see we haven't moved so it's entirely up to you what you'd like to do but for now I'm just going to tie this view okay now we'll hop back into the auto dock Network I think that looks good to go so I'll go ahead and simulate and we'll see what we're working with okay so the simulation is done and let's see what we have okay I think I've I I think I like that better it seems that the the movements a bit more organic I think the the friction has helped I'm just going to disable this and kind of navigate around here okay so let's just stop this and see what's going on okay so the collision seems to be working okay and let's just tab out of this and go into the green node here all right now I want to see the exact size that or the exact thickness I guess I should say of these particles when they're under collision so there's a handy node for that that's automatically created when using the velum shelf tools and that is vellum post-process and you can just disregard the first tab and head over to visualize and under thickness if you enable that you can see that the thickness of these corresponds to the grain size so we're all good for particle collisions or inter particle collisions I should say okay so let's just go back here all right so let's middle mouse over this and see what kind of attributes were created so we have velocity we have target path and we have position obviously mass what we'll use to color these is velocity and that's pretty handy we can just hit tab create a color node enable that and then we're going to use the attribute the velocity attribute sorry with a ramp by default it goes black and we're gonna put the range from negative two to just see what's going on there okay so it should be gray and I'll just enter V for velocity and automatically we get this kind of pretty sweet rainbow effect okay that's looking pretty good now some last touches that you might want to add will just navigate back to our camera are some randomizations of the particle sizes and the orientations so one of the easiest ways to do that is to drop eight randomized attribute note and do we have a P scale okay well we'll create a piece Cale attribute as well so we'll just go attribute eight under name okay P scale and it is a float so we'll keep the class two point and the type to float and come here under P scale I'm sorry under attribute name type in P scale let's enable that okay now by default what happens is these get globally scaled now we need to change the scale to point zero one to correspond to the scale of our velum grains and I'll just zoom in here and see what's going on so you can see we're getting a range of values here from zero to one and we're just gonna go sorry uniform and under min value and Max value will put 0.3 and 0.5 oops let's bring that to 0.9 okay and now you're getting a nice randomized number here now the thickness the inter particle thickness is still at the one value so if if you need if you need to kind of visualize that you can keep this at let's say we'll go one point one and point nine point eight five maybe okay that's pretty subtle I like how that's looking now another thing we want to do is create some custom geometry to be applied to each point so we're gonna lay down a copy two points note plug this in and before we plug in any additional geometry we want to make sure that we pack and instance this and this is going to save a lot of memory because currently we're working with 53,000 points so we'll create a spear make it a polygon and let's just see what that's looking like okay well come out so this is what our sphere is looking like let's just dial the frequency back just a bit and we will enable this okay and the purpose of chose this geometry is to show you that there's something that's odd that's happening here and that is the alignment or the orientation of all of these is somewhat uniform which obviously would not happen in reality so we're gonna have to find a way to randomize the orientation of each one of these points and that can be done relatively easily by coming back up here adding another randomize attribute randomize and the default is color so you can see how that's affecting everything which is quite cool yet these jellybeans but the attribute that we want to use is orient now by default nothing is going to happen because orient is actually a [Music] oops go back here uniform continues aureate is actually four-dimensional so we're gonna have to put four here and you'll see we get randomization of the orientation here which looks a lot more natural and if you are increasing the grain size and therefore the simulation time this is gonna help your vendors a lot to catch I mean you can already see what's going on here you're gonna catch kind of a randomized amount of reflections from your light source when rendering which is gonna give the appearance more of of sand or you know it's just going to break up the the regularity of the geometry and and give you a better result so we'll come back so I actually forgot a really important point during the simulation what you in order to to get clumping you actually need to enable an attraction wait so previously I just left this at zero after changing the repulsion value to 600 but this is very touchy so I've just added 0.0025 to the attraction weight kept the attraction to ten which was the default and if I play through you'll see we get just a lot better of a result so you can see they're breaking apart and kind of flying off in chunks you get some clumping as they fall down and I just think it looks a lot more organic and it'll help your your animations a lot okay so I'm going to again export to n play and we'll see kind of finalized result okay so n play has finished rendering the simulation intact with the color and let's just see what it's looking like okay so it's it seems similar at least to the result that that I was showing in the beginning of the video so hopefully this this teaches you a little bit about Vallon grains I know there was a lot of tutorials that are floating around at the moment covering this topic but I thought not a lot of them tell how to kind of contain the grains and and how to get something a little bit higher end with the results of them are just you know dropping them onto onto the ground or what have you so if you like this tutorial or you know you'd like me to cover something different in the future just I guess let me know in the comments I'm trying to make them better for the time being they're mostly going to be beginner tutorials but check out my channel I guess for more and and let me know what you think so thanks very much and you can get these free seen file as well as the redshift file available for download on Gumroad and also at patreon which should be in the description okay bye

Channel: Mark Parsons

Views: 18,040

Rating: 4.9555554 out of 5

Keywords: houdini, houdini tutorial, vellum tutorial, houdini 17, houdini 17 tutorial, houdini beginner tutorial, beginner houdini tutorial, cgi, satisfying, mograph houdini tutorial, satisfying mograph tutorial, houdini grains, houdini vellum grains, vellum grains, beginner houdini simulation

Id: RxbF-XI2TGw

Length: 40min 45sec (2445 seconds)

Published: Sat Jan 12 2019

Reddit Comments

[u/semmlerino]

Pretty cool. I'm starting to really dig into Houdini at the moment, so this is certainly interesting. Subscribed to you as well.

[u/[deleted]]

nice. gave you a follow on youtube too.