Houdini 17 - Intro to vellum

hello everyone and this is a basic tutorial on the new velum solver in Houdini 17 now this is not meant for absolute beginners in the sense that if you are just starting out with Houdini this can be a little complicated but if but it's not very complicated either so if you have basic knowledge of Houdini you should be able to do this okay but as I said like if you're an absolute beginner then this is not for you okay so the belem solver is kind of like an update to the older grain solver like it's the grain solver but with newer technology so it's a lot faster and it's also supposed to be a lot stable even though I haven't really done anything very complicated with it so I can't really you know comment on stability but it is as I said it is fairly simple to use and it is really fast so it can be used for three things you can use it for hair you can use it for cloth and you can also use it for grains and everything can also interact with each other and the nicest thing that they have done with this version is that you can do all of it at soft level like you can still do it in Dobbs but you can also do a lot of stuff at soft level itself so it makes the process a lot simpler okay so we're going to start off with doing basic hair and then I'll do cloth and finally I'll do grains okay so I'll just do like simple examples of all of them so you get an idea of you know how to work with it so I'll start off with a simple sphere or let's take one of the test objects so let's take big head and that takes a second to come in okay and let's do one thing I'm going to get rid of the color and everything so take an attribute delete and I'm just going to get rid of the it'll have like a material path yeah there we go okay and then let's just animate this I'm going to take a transform I am going to animate this so we move it here and then we'll do all clip all the key framing stuff that used to be here is now over now to the left-hand side and this has like other options in here but yeah there's like your big keyframe button so I can click that and then I can come ahead - let's try 120 and I'll just move it there and I can click the keyframe again okay and others which are in real time okay so we just have like a basic animation happening and then I can take a hair generate I'm going to keep the density fairly low so we'll keep the density to about about 50 and let's just connect the skin and you should be able to see here and then if I play this you know you should get hair sort of moving along with it because it will do a couple of things I'll turn off use guides and I will increase the length a fair bit so we can at least get some amount of dynamics happening over there and the next thing we want to do and this is important okay so for the hair to sort of stick to the geometry you need to make sure that the base points act as pins to the geometry so in order to do that what you need to do is like this doesn't generate any groups or anything okay so we need to generate that group so you do that through a forage so just take a forage primitive and we are going to just create a group of the first point so since they all start from below the first point is always going to be zero like that point is always going to be zero so we bring this in and all I have to do is take a group node and change this to points we'll call it roots you can call it anything you want and the base group will be zero so if you come in here we should have 665 per see you have 665 polygons and we have 665 points the base points in route okay in our group called routes so if you want to check it we can give it a color and just check it like if I give it a color here and I can pick up routes and let's say if I give it right see so they go you can see like the base point is red for all of them okay so this is the basic like this setup you have to do if you're doing here I haven't figured out any other way so far because it doesn't seem to automatically generate like a routes group but yeah this you will have to do okay then the rest is fairly simple you need you will get something called a bellum configure which is essentially a variation of the well M constraints node like these are all like well M constraint nodes just each one is like they've said the default values to something so we can take bellum configure hair so you put that in and plug in to the left and that's basically it like you don't need to do more than that just what we need to define is we need to define the route values so you'll find thing called pin to animation and click there and you can pick up routes see there you go so it generates the routes and yeah I think that's basically we can turn or match animation but not right now and then the rest is we need to take a balanced all work so just type in solver can you indicate okay and we'll get well M solver and what you need is it needs two basic inputs in the middle one is constrained so all the constraints that have been generated those those need to come in and the base geometry needs to come in the last node is for is for collision okay so we can that's option you want to take that you can take that but we will bring in the collision of the base geometry anyway so let's bring this in and let's bring in the constraint and if you just play this right now it should work so if I just come in over here and if you press play there you go so it's pretty straightforward yeah I think we need to turn on pin 2 yeah okay let's try this again yeah there you go so if you don't have not match animation it doesn't pick up the animation so now what we can also do along with this is we can bring in the the base geometry that we have so I'll just do like an alt click here and bring that into the last input and see you'll see like the the big head coming in and let's press play and there you go like it will collide with the head it's fairly fast like it this is about 600 curves and it does it almost real-time so I'll just let it solve till like the 120th frame that we had done yeah let's do one let's make it slightly faster so I can just come in here and I will pick up this frame and like what do you do is you if you've never done this before then keep shift pressed and drag a box in the timeline and then middle click and we can pull it closer and I can do it do the same thing with this as well so I can just take the first keyframe and move that a little ahead okay and if you don't want to see the collision geometry you can come into the velum solver and then in visualize you can turn off show collision so you won't get to see that anyway so it will fall and then it will move yeah that's better it's going faster so you'll get to see some movement yeah so that's basically it so this is how you can set up and then once you've done that much then we can use this to further generate hair okay so I can just take this and put it into another hair generate and again I'll just pick up the base geometry from here and I can pick up the points pick up the guides from there and what do you have to do with units like turn off grow unguided here and we can just increase the influence radius till it sort of fills up the whole thing and you can define like a little bit let's do one thing let's take a color and give it like a random color okay so I can just plug it in there I can see random and primitive and in order to pick up that color you'll have to come to attribute and point attribute and pick up yeah if you click that it seems to be giving an error so let's type in CD and it should do that yeah there's two points anyway so okay I seem to have lost the yeah let's calculate like 100 frames again the nice thing about this now is that because you have the velum solver like it's still a Dobbs node but because it has been brought directly into swap level and you don't even need to sort of like go inside it or anything it makes all of these basic setups really simple you know what earlier were fairly complex now these setups are fairly simple to do yeah and then if you want we can take like a clumped node so let's take a hair clump and let's do one thing let's just see what this will say dad yeah so again you'll need the you need the guides and you need the skin if they're looking a little weird like that you need to set the clomp mode to linear blend like extrude and blend looks a little bit weirder and then you can just like I can make it slightly thicker yeah what you can do is if you just want to give it some color we can also try it out here like I can take a wrangle and I can try to do let's play let's get color from bounding box and we'll have to recalculate again but there you go see now it get color from bounding box it looks a little bit better okay so let me just recalculate it like one last time and then I can just you know play through it again yeah so now that we've calculated everything there you go you know that you can play this and see so yeah so this is how you can do well um here so nothing overly complicated okay I'm gonna save these files and probably upload them and also I'll just save this here as well um here okay so this is the basic okay the next one we'll do is we'll take a look at cloth okay so I'll take a like a simple grid and you increase it to about say forty and forty or let's do one thing let's we mesh this okay so we can get like a triangulated mesh so I'll just take a remesh like drop it in there yeah and just lower the target length so it's relatively dense okay and then I can take I can take a transform and I will move it up but before that we'd also create a group to pin it okay so I'll just press two and I'll click let's say these two points and we will type in group and we will call it pin okay and then let's also take a rubber toy yeah for collision I'll just make it slightly smaller yeah and then I can take a vellum cloth and the process is mostly the same you know it is coming here and you'll get the pin to animation and pick up in and you see like those little dots that are being formed that's basically it yeah yeah you don't need to do you know more than that and then we can take a melon cloth we can take a vellum solver and again just plug in both of these and that's basically if I press play it should fall okay it it has this tendency to you know complex things like I get like a ghost are they God so if I what I really suppose if I change any parameter then it goes away okay but yeah let's also do one thing let's give it some color just so that it's easier to see yeah okay okay so if I press play and there you go now along with this what I can also do is I said we will bring in the test geometry here so if I press play it will hit that it's it is really simple to setup and the quality is actually quite good so most of it is fairly simple so if I come in here and I had like start to adjust things like if I had a stiffness then it will be a lot more stiff see you can also increase like the damping ratio now this is basic now let's say if you want to sort of tear this okay so that's that's fairly simple what I can do is let's come to the color and you will get a new node called edge fracture so click on edge fracture and if you press Enter and in order to see it because it doesn't show it readily turn on primitive piece and switch on show guide geometry so there you go so these are the pieces that you have if you want to see them click on this little like this location icon over there and see so those are the pieces that you have and you can increase them and what you can do which is interesting is the group still remains but what it has done is it has generated this new group called new points now if I just directly go into the velum solver and play this what is going to happen is that like everything will just stay apart so what if you want to stitch them together okay so after the velum cloth take another random constraint okay and we will bring in like this and that in here so these are the existing constraints and then we will update them and those flow back in here we don't have to get in the third one okay and then what you need to do here is this one will be called stitch points okay and the the target group or hold on like the group type is points and we need to pick up new points see so there you go so you're getting like these points getting stitched and now if you play this they will it won't break you know it'll remain stitch together if you don't want to see the color anymore just come back to the edge fracture and click here and the color will disappear so if you press play see they go so you'll get this now what you can do is you can do some basic stuff like if you come in here and you have the option for tearing okay so if I just turn on the tearing and let's play so it has a threshold value if it crosses that threshold value see it sort of starts to tear but now what you can do is you can start to play around a little bit with attribute so let's say if I increase the threshold so that it won't tear but I wanted to tear when wherever it is hitting so you can say scale by attribute okay and this is the attribute that we have in the way of this thing called breadth break threshold scale you can change the name so let let's call it break and we need to generate this attribute so what I can do is like this has to be done before this so I'm going to take or what yeah let's do it after this I don't I'm not entirely sure so let's take first let's take an angle node and we'll do it both like either either it should come in before that or after that but okay so I'll just do like F at break which is equal to one okay hold on what was it called break skin and let's try to pick that let's do ctrl C yeah I think there must be something called break but anyways let's do one let's put it before this and let's keep the value to zero and I don't let's play this and see what we can see so everything breaks yeah so what that is doing is taking break scale but even though there is a threshold value since it's coming in by attribute and the attribute value is zero it just breaks like if I turn that off to no scaling and press play so now nothing breaks and then if I say scale by attribute then because the value is zero everything breaks so now what I can do is I can keep this value to one and then I can just take a simple paint node so we'll take a paint node here and this is going to be called break scale so we'll just copy this well do control C come in here say override color and paste that attribute and let's keep this value to like very low and I can just come in here and paint it yeah so these are the areas I want to break yeah so hopefully if we have done this right if I press play so there you go now what you can do is because you get these gaps in the middle okay like these are not very good so what I realized was yeah let's just turn off that collide yeah is I you should take a fuse okay this is a bit of a trick so just take a fuse and like increase the value till they all sort of you know failed together yeah as it will break into they'll all move apart anyways and then you'll get the stage but otherwise it looks you know stitched see so now you don't get to see those like increase it enough till like everything is fine yeah so then you go don't get to see those gaps now you can also you can also put in your own curves if you want you know so that is also an option like if I come to the edge fracture and I'll do create in context and if I type in curve and let's say if I just you know draw my own curve and what I can do is like I'll just duplicate this so I'll do control C control B and you can put in your own edge fracture see so you're getting like yes you can see the curve coming in but if you just wanted to split using just the curve turnoff initial pieces so you will just get see that the rest of it should automatically work because the points are being generated procedurally but we'll have to adjust the paint again so we'll take a paint and we'll just paint it again so the same thing no yeah and very low and the speed yeah do one thing yeah okay so come back here and if we press play now you'll get like a sea so they go and only fairly simple stuff so you can either tear using like the basic worn I fracture or you can tear using custom curves okay okay so I'm going to save this and let's call this vellum cloth and the last thing is grains so grains is fairly simple so I'm just going to take a sphere and I'll do a points from volume so just to fill it up with points okay like not so many this lower okay also take a transform and we'll move it up okay and then take a take a vellum green and just plug that in and they could automatically sets up like the size and everything for it and then we can just take a vellum solver now what you can do which is interesting is if this has an inbuilt ground Collider so if I turn on ground position you'll automatically get a ground collider and if you press play it will just yeah I think whoa okay hold on let me just try to lower the grain size let's try 0.02 now 0.06 okay hold on let's Jeeter this a little bit okay yeah there you go that's better it was too uniform I think that's what was causing the problem okay and then you can also come and do like forces you have inbuilt gravity you have a bit of wind and I can just take we can increase like the static threshold so it becomes like the ground becomes a little rough so it doesn't spread out too much dynamic scale yeah there you go okay so the nice thing here is that everything can also because all of it is going through the same solver everything can also interact okay which is what makes it interesting so if let's say I want this to fall on a piece of cloth so I can take a grid here okay and let's do it let's turn off the ground position so I'm going to take the grid will just increase the segment's a little bit and let's do a group so I can just press two and we'll pick up three for yeah and call it the same thing pins and we'll do this we'll set up the vellum cloth and set up the pins and then we were to merge all of this together okay so we have our cloths and we have our grains and then what you can do is just take a mulch so I'm not sure about this but the way I've been doing it that you merge the cloth you merge the the geometry inputs and then you also merge the constraint inputs and then you bring them both in over here and hopefully that should work so turn off the ground position and then if you press play you'll see them both interact now the one thing that I forgot to cover it is actually really nice is that you also have the option within the velum solver to give it basic particle forces okay so what you can do is this is fairly simple just double-click on the velum solver and it will bring you in and it'll just say wire pop forces into this so just take a force and you'll get pop force and if I just plug this in and I'll give it some noise okay like we'll just increase the amplitude and that's basically it so if you press play see there you go you should be able to see a little bit of noise sort of flowing through the whole thing or if we just if you just bring this into like a cloth solver if you just do the cloth okay like I can bring just this in so I'm getting rid of the grains temporarily and even in the group I'll just get rid of these two points so if we press play you'll get this and let's go in and we'll increase the amplitude to like a fair bit see so there you go so you'll get like a decent little so if you want to a flag or something I think we can do that like I can turn off the gravity altogether and I can do wind in z-axis so let's try the wind to be like four and if you press play so there you go this is kind of stupid but yeah give it a gravity of let's say minus three so it sort of Falls a little bit so yeah everything can interact like that's the nicest thing about it like you can have all of it interact I don't know how this would look now but they you know yeah that is not what we were expecting but there you go you can see like when it moves and it hits the cloth it does react anyway so that's basically it so this is everything as far as the basics of Menem are concerned like I haven't as I said like I inst I installed it yesterday but this is the first time like the Dynamics network has been fairly simple the few things or the one major thing I haven't been able to figure out as yet is how to break constraints over time like how to animate breaking like let's say if you want to break it exactly at frame 35 if you animate the break the break threshold or anything it doesn't seem to work so there is something missing like even a dynamics level I haven't been able to figure out how to do that but I that will come in time I think in a few days they'll probably also release some kind of a vellum master class so it will that will help out a lot more but until then I think this is a decent enough starter for I think for about like say 60 to 70 percent of basic dynamics work this is pretty good you know like this is a good enough place to start you want to do like basic Terry you want new hair move your hair moving in the wind if you want to do basic grains and stuff like all of that sort of works out pretty decently without doing too many complicated things I think if in the future they can also bring in like the bullet solver at soft level that will be great you know like rather than having like just keep the really complex stuff to Dobbs and if you can have like the basic bullet solver over here like at geometry level or like even the basic fluid solver a geometry level I think you know it makes life a lot easier you don't have to jump through multiple networks to do things like you can still do the complicated stuff and do that and ops but for basics I think this works out a lot better so anyways this is the basic I'll upload all three of these files with with this tutorial and if you have any complicated questions don't ask I don't know as I said like I'm just starting to figure this thing out as I figure out more complicated things I will make more tutorials but right now this is it okay so if you have if you have basic questions I can answer those if you have complicated questions find somebody smarter than me I am very sure they can figure out more yeah so that's basically it

Channel: Rohan Dalvi

Views: 40,973

Rating: 4.9030304 out of 5

Keywords: houdini, vfx, tutorial, vellum, grains, cloth, hair

Id: frTdG_FJFlQ

Length: 31min 37sec (1897 seconds)

Published: Fri Oct 12 2018