Couch Tutorial Part 2: Cushion Simulation

welcome to the fun bit of the tutorial certainly more fun uh than the first part where we just did some basic blocky shapes in this part we are going to be making the couch cushion and by that i mean the backing right the bit that you rest your back against or the seat it's the same method for the seat it's essentially making really the hardest part of a couch it's the biggest uh most challenging part when you see a lot of 3d models online of couches generally things fall apart here right it getting getting the wrinkles to actually look right and this is you know it's understandable that uh if you if you didn't have uh simulation tools or anything like that if you were trying to sculpt this by hand which some sculptors can do well um it's just really really hard to do that to sculpt in the wrinkles accurately and so that's not the method we're going to do thankfully we are going to be using uh two tools in blender the first a cloth cloth simulation to create the basic shape of the cushion um and then the second part using the new cloth brushes which is going to add some slight variations to things so i'll show you that that two-step method and that's something that it took me like far too long to figure out i probably made about 50 to 100 of these cushions to prepare for this tutorial trying all different methods from multi-resolution to pure sculpting to pure simulation to weight painting so much mess um and i figured that this is the best method the one that i'm going to show you so to start with we need uh the basic shape for the cushion right so it's this square shape here so i'm going to add in a cube scale this down position this roughly there if you can hear my baby in the background i apologize but now you got a little taste of my life and what i have to put up with on the day today something like really irritating about when a baby just goes it's just like spit it out man you got something to say say it don't just you know anyways but you can't say that because then people think you're a crazy person but every parent thinks it so anyways so i've got this uh i've just scaled in the cube now you'll notice that i've made this far thinner than the reference appears right so the reference has you know an inflated looking cushion and the reason i've done that is that we're going to be using the cloth simulator with inflation so this is going to expand beyond what it is so actually this size that you've got here you really want that to be um if i can find it maybe this is a better picture trouble is it's all like zoomed out then yeah look how tiny that thing is let me get in here aha uh can you see it but kind of like where the seams actually are like that's where the initial size of the cushion was and then it's sort of like inflated beyond that so it's actually really thin and then the inflation you know expands it out okay so the cloth simulator which is what we're going to use um sculpting is the same everything is based off the geometry that you have so currently we've got exactly eight vertices that's making up this uh this shape here so we would not get anything good out of this so obviously you need to subdivide it right now if you were to subdivide this in its current state and i'll show you this but just don't follow what i'm doing right now um if we were to just like increase this and create uh detail you can see we now have more detail we have more faces across this mesh however the detail is not uniform right it's it's performed the same number of subdivisions across here as it has here now this is a problem whenever you're sculpting whenever you're doing simulation specifically because now you have more detail like horizontally on one axis than you do in another and that is a huge problem and i see that a lot i've seen several tutorials actually on youtube um where they start with a mesh that's actually like this and it's just setting it up for failure because you'll have detail in an area more in one area and the simulation won't work right it'll try and like treat it i don't know like more weight for this part and it just looks horrible so the the first thing you need to do before you do any cloth sim anything like that is you want to get square uniform faces across the entire mesh so what i mean by that is um i find like the shortest face shortest face like this and then i do a loop cut so ctrl r and then scroll up on the mouse wheel until looking at this and just sort of judging by your eye what looks like i'm getting uh faces so that looks like 14 cuts and now i'll right click to confirm it in its place and those now look like faces across there you can adjust this here if you wanted to after the fact but uh but that looks pretty good and now obviously i need to do the same thing going this way uh vertically so ctrl r scroll up and how does that look i think that's actually pretty good let me test that 11 is too much yeah that's good okay it doesn't have to be perfect but i want it to be perfect so uh that's good we now have square faces basically square faces across it nice and uniform and that's good so now we can get to the the cloth simulation phase now we are going to be using a subsurf modifier so uh so add one in like this um and when you add a subsurface modifier you can see that it smoothes out the corners we don't actually want that we want that to be we want these edges to be sharp so what you need to do is enable simple instead of cap more clark which means when you change this you won't see anything happen here but when we add the simulation uh it will actually change it so um let's just set this to two and two uh simple and then go to your simulation panel is that the simulation it's physics physics properties and then click on cloth right now it might have disappeared because i'm on a different frame if that's the case just hit shift left arrow and it'll go back to frame number one now you've got a whole bunch of settings here but i just want to point out first the sub surf modifier is above the cloth simulation that's important because you wanted to add the detail and then simulate on top of that we don't want to apply we don't have to apply it we want to be able to come in here and play with these values if we need to based on what we're seeing in the simulation so it's actually really good it's non-destructive which is a complicated term but it just means you can change things after the fact anyways so we got the cloth sim and if we were to hit spacebar to play the animation this is what we would see it's falling and it's clipping through everything and that's fine and dandy nothing is happening because there's nothing for it to collide into or anything like that um the big value that we want to give it is underneath this is cloth physical properties here we go pressure okay pressure is what is going to inflate our cushion and this is really where like 90 of the look comes from the other 10 is really like the size of these faces everything else here is pretty much irrelevant tension shear bending bending actually has some effect i might tweak that in a little bit but all these other values like the defaults like i've tried playing with everything and it just like it made no difference for this what we are doing here um it's almost all controlled by pressure so what pressure does is you check the box and then you assign a value let's just start with something big uh let's go 10. and what you'll see is that it has started to inflate the object now the way pressure actually works is it's according to each face right so we've got faces it's a closed mesh so it is evenly like forcing the faces out which is not actually inflating the volume which is what you'd think um and you could actually see that because if you were to delete um let's say one side of your cube obviously don't do this but i'm just using it to show you and then you were to like ramp this up um you would see that it starts to fly in one direction or at least it now it's starting to go in one direction right so pressure is is it's it's a weird sort of concept it's not actually inflating it like you would imagine something inflating in the real world it just appears as if it is when you've got a closed mesh it's pulling each of the sides in equal sorts of direction so it looks like it's inflating even though it actually isn't so i don't know if that's relevant you depending on how deep you go into this it might be but anyways so uh so it we got pressure but it is falling now i was against initially like changing these values because i find like a lot of problems like people do like simulation tutorials and they just disable the gravity like they treat it like gravity is not important like the real world doesn't have gravity like a cushion has gravity so why wouldn't you want gravity on your mesh the problem is is that this is so hard to control pressure with a falling thing that's colliding into something else it starts it just becomes like jelly and you can't control it um things start to like pull out and it's and then you end up like doing weight painting trying to control which parts have more pressure than others it was a nightmare and then i realized like i just you just gotta you just gotta kill it kill the gravity um and this is what we're gonna do so when you get that now you just have the pressure that's it it's just pressure and it's in space there's a cushion in space and that's what we're getting okay now you'll notice that it is heavily deformed and this is something that i've been banging my head against the wall for most of the last two weeks is that pressure is great however it very quickly deforms the original shape into something that you cannot really control so essentially the reason this is happening is that this face on the front here is much bigger than these faces here and so therefore this part is getting a lot more pressure um than these top parts here and now you can do weight painting and everything like that but it's really overkill and it doesn't really solve the problem because then you end up with something that doesn't even have proper wrinkles and blah blah blah anyways the solution that uh that i figured out is that uh you really only need one frame to work right and towards the front in the first few frames uh it starts to look like the reference all right there we go loaded it into pure rf so i don't have to deal with the website but it you know the reference is you know it it's got a little bit of uh of push to it you know it's it's a little bit what's the shape not a bean bean bag it's a little bit stuffy but but the the actual shape itself of the you know rectangular sort of soft edge thing it's retaining that but it has uh some wrinkles down there so really we just need to find a frame at the front here that works um and currently it looks okay but there's not nearly enough wrinkles so the the detail of your cushion is really determined by i mean there's a few values in here that that um really the biggest one is bending that can have some sort of impact but the biggest one of all is just how much geometry you actually have right so this is with this amount of geometry and then when we increase this by the way it bases it off of the viewport amount not the render amount just for the the cloth sim um anyways when you do this you can see it takes a lot longer to simulate but you get much more wrinkles and this is actually a interesting point you would think then that like if you just keep increasing that that you would end up with a more and more realistic looking cloth simulator right but that's not necessarily true because along with increasing the detail you're also kind of changing the real world size right like when i simulate at this this is too high for the size of this cushion and the amount of wrinkles that will get in this if i can keep yammering on whilst it generates um the amount of wrinkles that we'll get on this doesn't make sense for the size of this cushion it would probably make sense for like basically if you go too high on the subsurf you can end up with a cushion that looks like it the real world size would be like the size of a house or a building right um so yeah there's going to be more and more detail the larger something is because cloth can only have so many wrinkles logically depending on the size of it if that makes sense right so too many wrinkles here i mean it's not it's not terrible but it's probably too many wrinkles for the size of this couch so don't automatically think like yeah i'm just gonna let it simulate overnight and then i'll have a hyper real cushion like you don't need to thankfully um you can just go for something moderate like this look at the amount of wrinkles that you get compare it to your reference and go like yeah is that more or less than than what i want and this is this is definitely fine okay so you know we could pause it here like we could you know freeze it say this is the frame i want to use but we can also tweak it a little bit more so this pressure amount here i realized pretty late actually just yesterday um that the uh the amount of wrinkles that you get here is also determined by how fast it is expanding okay so if you were to set this to 50 uh what you would find we do have to wait for it to sort of go is that you end up with less wrinkles right so you can see that the the d like at this point that's way too deformed for us to use it and the amount of wrinkles we get we've gotten is really small right so you could see like you know this is maybe even this is probably the size of the the cushion that we want in in terms of defamation but there's not there's hardly any wrinkles appearing there whereas if you went for a lower amount so five um 1 10 of what it was just now is it will fill it up slower and you can see it gives it time for wrinkles to appear so then it like clicked to me i'm like aha that's the key figure then is like to if you want to control for the shape of this as well as controlling how many wrinkles you get you need to adjust this pressure amount to fill it up slower or faster depending on if you want more wrinkles so if you want uh more wrinkles then you would slow it down so that it would fill up slower right you end up with more frames before it gets to the size that it needs to and therefore you end up with more wrinkles if you've got too many wrinkles then you increase the pressure size so you can see like now i've got like this big bend here and it sort of looks like it's like a loose sort of uh cushion so it's like a totally different effect and yet it's all controlled by this this pressure amount here right so that's what i mean like the pressure is really uh like the biggest factor here in making a couch cushion um again we just need one frame for it to look right so you know we thankfully it's at the start of the animation so you don't have to wait forever for it to sort of come around to the right shape um that looks pretty good to me now you could if you wanted to by the way change your bending amount so i'll just very quickly show you what that is depending on the couch you're doing you might want to adjust this if we set that to 20 so instead of yeah basically 40 times its default you'll see you get far less wrinkles and the wrinkles that you do get is bigger and chunkier and as well as that it also retains this edge right and that's because uh yeah it's bending less so that 90 degree angle that it starts with it's trying to retain that and keep it sharp now if you do that though um sorry if you want that you don't necessarily have to change this because along with this you end up with less wrinkles right so it's more suited for something like leather and it's like maybe if i want fabric but i do want there to be an edge when we get to the cloth sculpting stage next uh but using the cloth brush i'll show you a way that we're going to do some detail around the seams so you don't necessarily need that anyways let's uh i don't want this tutorial to be like hours long so let's set that to 0.5 this is what i'm going to go with let's see how this comes out all right that is pretty good by the way if you go shade smooth it can kind of give you a little bit of a look at how it's going to look um yeah with proper shading um okay so how big do you want it how big do you want it how puffy do you want it looking from the side okay comparing it with the reference does that make sense for the type of couch that we're going for and i think it does i think that's that's fine so uh when you apply this uh you can't go back well you can if you've just done it you can probably have enough undo's to undo the operation but if you were to get sculpting later on and then go oh actually i need to it would be good if i could recalculate that cloth sim it's gone so what i like to do before i apply anything don't worry about that that's my watch just interrupting tutorial i duplicate it shift d um and then i just move it to the side like so and then this i hit m and then move it to a new collection which i called unapplied and then it's moved it to its own collection and then i just uncheck that box right so it's hidden and if i need it it's there i can go back to it and recalculate it now that i've done that i hit apply and then apply again on the cloth sim and that is it we now have okay stop go back ctrl z control z because we've just done it there is one more thing and i'm glad i noticed it before you apply it later on we are going to be uv unwrapping this guy because we want to apply a texture to it right fabric texture it is a lot easier to uv unwrap something when you have started with a base mesh like this than it is later on because it's then going to try and figure out the shape of it and do all this weird stuff it's a pain so it's a good idea to uv unwrap it before you apply it so okay uh we just need to add some uv seams in here and thankfully this is a couch object where there is logically real seams in real life so it's very easy to uv unwrap all we're going to do is go select select sharp edges and that will select all the edges oh and this is in edge select mode by the way so hit two if you do it in vertices mode that's wrong you want to go edge select mode select sharp edges then go ctrl e and then click mark seam and that is it then we go to the uv image editing tab up here and then hit u unwrap okay and if you see a little alert down there that says like oh something's non-uniform that's because the scale of this uh is not set to one so make sure i mean it's it's the cause of half the problems you have in blender is when the object has a scale that's not one one one so hit ctrl a apply your scale then hit u unwrap again and it should then correctly uv unwrap okay now that we've done that we can apply it but of course we have to recalculate the simulation because we've just done some editing i don't know how blender decides it but anyways thankfully it doesn't take that long and that's pretty good good so now we hit apply and apply and now we have our object here tada it's uv unwrapped it's ready to go and it looks uh pretty good and if you want to see it like yeah add another subsurf modifier after it and you'll like smooth out those shapes because that's what we're going to do when we render it anyway um and you can see sort of sort of how it looks it's not it's not too bad right it's got the right like smooth deformations it's got wrinkles where there should logically be wrinkles and overall it looks pretty nice but doesn't look that detailed and that's what the next part is for so in the next part we're going to be jumping into sculpt mode and use the new cloth brush thank you apple watch to add in extra detail move it around so a lot of fun go ahead click here and i will see you in that video

Channel: Blender Guru

Views: 388,906

Keywords: blender, tutorial, cloth simulation, cloth pressure

Id: 4h097E4pRCw

Length: 19min 43sec (1183 seconds)

Published: Fri Jul 03 2020