26 Essential Blender Tips for UV Unwrapping Subdivision Surfaces

if i had to guess i would say that uv unwrapping probably isn't your favorite part of the 3d process or maybe that's projection pun intended because traditionally it hasn't been mine but over the years i have found some good tips and tricks that make the process a whole lot easier faster and sometimes dare i say even a little bit fun i'm jonathan lampell with cgcookie.com and i recently released a course about creating this character in blender his name is pothead and we made him all the way from default cube we did the initial modeling and the uv unwrapping and the texturing but in this video i want to take the most important uv unwrapping tips and just distill it all into one single video that's a little bit shorter more concise and more algorithm friendly so let's get right into it the first one and the most basic is just to use a uv grid whenever you're unwrapping so the way to do that is if you're in your uv editor or your image editor just go to image and new you can name this whatever you want and have whatever resolution but just set the generated type to uv grid or color grid once you do that you can just drag and drop it into your shader editor and use it there so if i switch over to solid view i can actually see this if i select the node here you can see i have two different grids a small one and a big one and whichever one's selected is what shows up in the 3d view that's because in the viewport settings for solid view under color i have it set to texture so this grid is going to really clearly show us if there's any stretching or how the uvs are positioned on the texture so i'm going to focus on the pot here just for the first example i'll let slash to go into local view tab into edit mode here and i'm going to clear all of the seams that we have so far so i'll just select everything with a and in edge select mode right click and clear seam and i'll also just reset the uv so we have a blank slate to work with so i'll hit u to go to my uv menu and reset all right so if you've unwrapped pretty much anything in blender you know that the way to create a seam is just by you know selecting some edges here i'll select the loop that goes around the bottom of the pot right click and mark seam and then in order to actually have this affect the model we have to select everything with a hit u and unwrap so that's fairly fast as it is but there's an even faster way and if you haven't been doing this so far then you're going to absolutely love it and that is the combination of live unwrap and edge tagging so live unwrap means that once you place a seam it'll automatically unwrap the rest of the object for you so you can turn that on under options and live unwrap there's an option for in the 3d view and there's also an option for it in the uv editor so i'll turn it on for both here then if i want to take an edge and mark a seam i can just select it right click mark seam and then it'll unwrap for us so that's already really cool but let's say i want to take let's say the front part of the pot i think it's this edge right here all the way up to the top or this edge right there well what i would need to do is hold ctrl so i'll select the bottom edge hold ctrl and select all the way to the top here and then under the pick shortest path settings i can set the edge tag to tag seam now really all i need to do is just select one edge hold ctrl select another edge and we'll get a seam created between the two so this is extremely fast and we can also get rid of a seam if we select one hold ctrl and select another edge if there's already a seam there it'll get rid of it so if we want to do that for an edge loop we just want to select the edge loop and then mark seam but if it's just a path of edges that's not a loop then we'll use the ctrl hotkey that way we can unwrap things incredibly quickly i'll go ahead and place a seam along the back here and when i'm working with my uvs i often like to turn off subdivision surfaces in edit mode so i'll go to my modifier properties and under subdiv i'll have this little edit mode icon turned off if it's on then some of my edges are hidden and it's a little bit hard to see but if i want to see the result of the subdiv i'll just hit tab to go into object mode really quick and look at the result and then tab back into edit mode but here what i'll do is i'll just create another seam all the way from here all the way down the back all the way towards the bottom i'll just hold ctrl select this edge and i'm done i'll do the same thing with the loop that goes all the way around right click and mark seam alright so already we have a pretty decent unwrap that we could start painting on but one thing that i'd like to do is straighten out the uvs for the inside of the pot and the outside as well because right now you can see that they're curved in the uv editor now that's not a huge problem but it also means that we can't paint straight lines and i'll show you what i mean if i go into texture paint mode and i'm just using the stroke method of line here if i want to paint a stroke straight up and down you can see that if i zoom in we're going to get some jagged edges now since this is a reasonably high resolution texture and we're using you know this whole 2k texture on just this area then it's not really that visible but as you go down in texture size it's going to become a lot more obvious i'll go over to my texture slots here and i'll pick my smaller texture just like so and if i try to draw a line you know i can't draw a straight line here and we get that stair steppy artifact pattern so i can't draw a horizontal line either and sometimes that can cause some real problems now in this case it probably won't be too big of an issue but if we're working with some really small text or something like that or we have a larger texture but it's stretched over all of our objects it's a lot better if we can just have some clean vertical and horizontal lines so what i'll do in order to fix this is use follow active quads i'll go back to edit mode here and follow active quads is just a thing that allows you to line up all of the rest of your island based on one quad so if we go over here i'll just pick one quad i'll go to three to go to face select mode and right now i have sync selection turned on and let's say we take this one and since i selected it first that's going to be the active quad if i hit ctrl l then i'll select everything that's linked to that that's just going to be the rest of the uv island here and then i can right click and follow active quads and you can see that the rest of this island has now followed the edges of my quads so all the horizontal lines have been angled to match this and that's been extrapolated out so it started out at a pretty gradual angle but it just gets more and more extreme as it gets more extrapolated so really in order to actually flatten this out what we want to do is make sure that the original quad is completely straight now you can use follow active quads in the 3d viewport but i find that to be pretty confusing most of the time so i really only use it here in the uv editor because i think it makes a lot more sense because it's following the quad in the uv not in the 3d space so if you've ever found this command to be confusing that's why so just use it in the uv editor and it'll make a lot more sense so let's just take one of our quads here that's already fairly straight i'll choose this one and let's straighten that out even more so i'll take the top edge here i'll go to edge select mode and i can either hit s y and 0 to scale it to 0 along the y axis or i could use the align command right click and align y then for the sides i could either align x or i could also just use the align auto and it will pick whichever axis it's closest to so now that we have a quad here that is perfectly straight then i can select it ctrl l to select everything that's linked to it on that island right click and follow active quads now we have a perfectly straight island that's exactly what we want this is going to be much easier to pack so it'll save us on some texture space as well as we can now draw our clean and straight lines but the problem with using follow active quads and live unwrap is that if we unwrap this again all of our hard work is going to go away so if i go to edge select mode here and just create any other seam that'll snap back into place and we don't want that so the next idea to know about is pinning when you pin a vertex in the uv view it won't move as you unwrap so let's say we just want to pin these vertices here i'll select all of them with my box select and hit p to pin then if we were to create another seam here just like that you can see that all of the rest of my vertices moved but those didn't and actually that also pinned the ones at the bottom there so let me hit alt p and just pin one in the middle here so you can see this better p to pin u and unwrap and you can see the rest of them snapped back into place but those didn't so what i'll do is once i've straightened everything out i'll select the entire island and you'll notice that it also selected all of the vertices over here on the left because these are sharing vertices in the 3d view and since we have sync selection turned on anything that's selected in 3d view is also going to be selected in the uv editor so this is a point where i'd want to turn sync selection off here and i'll unpin everything just to make sure with alt p but then i really only want to pin this one island and nothing over here on the left so i'll move it off to the side here i'm moving it off to the side by the way because once i pin something i'll just hit p to pin here and then if i unwrap everything again you and unwrap it gets ignored from the packing and so things get packed on top of it and i think that's just a little bit messy and hard to see what's going on so if i want to pin something i'll usually just move it off to the side here just so it doesn't get in the way and also i'd have to do my final pack later anyway and unpin things at the very end which i'll show you in a little bit so it's just a reminder that you know i have to come back to this later but at the moment i don't really want to be distracted by it so once that's pinned and moved off to the side then i can continue working on the other parts of the object one thing i do sometimes in this case it's not really too helpful but if i finished working on a piece and i'm working on a more complex object what i'll do is i'll select everything with control l that's on that island and if i set the limit to seam it'll stop at just that island and i'll hit h to hide so that i don't see it in my 3d view now here i'll hit alt h to unhide it because i don't think it really matters too much in this example but when we have a more complex object and other parts are hiding other parts then i'll just go through and unwrap piece by piece and then hide things when i'm done so that i don't accidentally mess that up later and i'm also not distracted by it as i'm moving around next i'd also like to straighten out the outside of the pot which is this uv island over here on the left but this one's going to be a little bit more complicated because on the right we had all parallel quads and so it worked very well with follow active quads but over here we don't we have these areas where some of the quads are going off in diagonal directions and some areas down here where we don't even have quads at all we have some triangles so that's going to throw a big wrench into things because if we try to use follow active quads and i'll just do it on one face here ctrl l right click follow active quads we're going to get a giant mess just like this so i'll hit ctrl z and i'll undo that and my first thought was that we could separate out the pieces that shouldn't be straightened from the pieces that should and just make them separate islands but that doesn't quite work when you're working with subdivision surfaces and let me show you that now so if i go into edge select mode and i just create a seam that goes all the way up and around on this piece here you can see that it looks great in edit mode but as soon as we look at this with subdiv you'll notice a lot of stretching that's because the uvs in these areas are being pulled towards those corners and we can actually see this if we select everything with a and let's just zoom in on this area over here and let's turn on subdiv in edit mode and in the uv view just over in overlays make sure you have modified edges turned on and then you'll see the subdivided edges being pulled up and towards those corners now we can change this behavior if we go to the subdiv modifier go down to advanced and change the uv smooth but unfortunately none of these options are going to fix this problem it might make it slightly better in some cases but all of them if you're creating a hole in an otherwise smooth surface it's just going to have some sort of pinching so i'll leave this on keep boundaries for now and we'll come back to this in just a little bit so i'll actually go through and remove these seams and it would be a lot better if we could just keep this as one solid piece and just straighten everything else around this so i'll right click and clear those seams just like so and we'll do exactly that what we'll do is follow active quads but just before we do that command we'll deselect all the pieces that we don't want to be straightened out so here i'll just select one component in the 3d view ctrl l to select everything that's linked to it set seam as the delimit that way we're working on just this section here and then just like before i'll straighten out one of these quads i'll pick this one here in the middle since it's already fairly straight i'll go to edge select mode right click and align auto and let's turn off subdiv again there we go right click align auto let's do the bottom and left side there we go so we have one face that's already pretty good then i can hit ctrl l to select everything that's linked to it and now i just want to deselect those areas that i don't actually want to be straightened out so i'll use my box select and just deselect all of these faces right here in the middle we want to make sure that the vertices on the outside are still selected there we go and let's do the same thing over here middle mouse button and drag and we might have to go in and reselect some of the faces on the outside just to make sure but for now let's just deselect the inner parts and i'll hit b and box select and re-select these outside pieces that i do want to be straightened that'll make sure we get those side vertices there and let's grab these faces as well okay once we have that then i'll go back and make sure that this is the active face by shift deselecting it and then selecting it again right click and follow active quads now for whatever reason that'll still uh do the follow active quads on the ports that we've d selected only when sync selection is off so it depends on which mode you're working in gets a little bit confusing but one way to kind of get around that is hit ctrl i to invert my selection hit h to hide so now nothing can happen to those and then try again so let's just select our straight quad again right click follow active quads that's been straightened out but you will see that we did miss a little bit over here or it got stretched in a little bit the wrong way so we do have to clean this up manually it just happened because we have this giant hole and it wasn't quite sure how to line things up so that's a pretty easy fix actually we just go to vertex select mode here and set our snapping to vertex grab these vertices pull them up and snap them up there so generally you won't have to do this if you're just working with one big complete piece but if you're working with things with a lot of holes in it there might be a little bit of manual cleanup needed okay then for these next to the holes i'll just move them up and snap them in the y direction and there we go now since this is already straightened and we don't want it to move i'm going to move this off the side here and hit p to pin for all of these vertices and i'll hit alt h to unhide so now we still have these pieces over here that haven't been pinned but remember that this vertex is actually the exact same vertex as this one over here but this one on this island isn't pinned while that one is so really all we need to do is hit ctrl l to select everything that's linked to this island and unwrap it again because everything that's pinned won't move everything that's not pinned will move it'll just snap it right into place so if i hit u and unwrap then that'll just jump right over and over here we get a pretty near perfect unwrap right there and over here there's a little bit of stretching but that just means we should probably separate out these inside pieces but if we go into edit mode here you can see that we get a perfectly smooth result over this area so that's how you unwrap something that's partially straight and partially not but let me just cut out these pieces really quick i can just select these edge loops that go all the way around these holes pretty much any concave area almost always needs to be cut out just because there's not going to be enough room for things to unfold out in 2d space i'll right click mark seam and there we go now we're going to get a much straighter result so now we're almost finished but we have a lot of stretching here at the bottom and that's because we have a seam that's splitting an area right between where there's really small faces and really big faces and this disparity is what's causing a lot of the stretching so what we need to do is just place the seam in an area where it's between two smaller faces or between two bigger faces but not between two faces of drastically different sizes so one way to fix this is just to add another edge loop and if i turn on subdiv in edit mode hit ctrl r and pull this up then you can see that we've fixed that issue right away but if we didn't want to add any extra geometry we could just move this seam and place it up here instead but right now that's a little bit complicated because we've pinned all of these vertices so we'd have to go through and unpin them by going on to sync selection going into edit mode taking all those vertices alt p and un pin just like that and then we'd have to make this a seam right click mark seam let's also hit control plus to grow that selection and alt p and unpin those as well then let's see if that works right click clear seam and there we go okay it looks like we have an accidental seam over here let's find where that is oh we still have this edge that we need to get rid of so i'll right click clear seam and there we go so that's just another way of fixing that issue we just kind of punted the seam up a little bit to where it's between two tight edges and now we don't have any stretching whatsoever lastly you will notice that we have some stretching here right along the seam on this side and it's really hard to see exactly what's causing this because there are no duplicate vertices all of our normals are fine it's just kind of coming out of absolute nowhere but this actually has to do with how the uv smooth is working in the subdiv modifier if we go down to advanced and set the uv smooth from keep boundaries to keep corners then that'll fix that right away but i want to show you a more extreme example just so you can see it more clearly so i'll go into edit mode here and just really quickly hit shift a and add a cube let's move this off to the side and let's hide everything else just temporarily if i add a bunch of edge loops here and tighten this up just like that let's add some on the bottom and at the top and then we look at the result if this is set to keep boundaries as it is by default we're going to get a lot of stretching along every single seam and we definitely don't want that so you'll find this when you're working with subdiv pretty often especially with hard surface shapes it doesn't happen that much with organic characters but just in case if you do see some stretching along a seam then check the uv smooth and set it to keep corners there are a couple very few cases where something like keep corners junctions and concave works better but just play around with the different settings and see which one works best for your project now since we're looking at a cube anyway i want to share with you one little trick i have for figuring out where to place seams because i think for beginners that's often one of the more complicated parts now obviously a cube here is pretty simple but how do we end up getting to this cross shape well i'm going to go through and clear all of our seams here which actually don't think there are any seams so i can just go to u and reset start with a blank slate and what i'll do is i'll either treat something like a cube or i'll treat it like a cylinder so if i was reading this like a cube what i would do is i just take these edges and go through all of the flat faces so this even works with a more complex object just separate out the front separate out the sides separate out the bottom all of that i'll just take all of these corners here and i think we got some over here okay right click mark seam so now i've placed seams along all of the sharp edges and we've separated this out into the front back and sides but we're wasting a little bit of space here if i go to u and unwrap that way i can just increase the margin just a little bit here then we can see that these are all actually separate islands and this is a little bit wasteful because the more islands we have the more space is taken up by padding and all that space we can't use in our actual texture so we want to have as few islands as possible so that we get as much textile density onto our actual object and not in the surrounding margins but we also want it to be a shape that packs well so that we can also just pack things in a way that we can maximize our texture space so what i'll do is once i've separated absolutely everything that i think i need to pretty much all sharp edges or just any part of the object that looks like it's a different piece when in doubt create a seam and just separate out everything and then once you do that then come through and stitch things back together and i found this to be a really good way of figuring out exactly how our island should be shaped so let's say we have all of our seams here and i have sync selection turned on but i'll go out of subdiv just so we can actually see this better now i can really easily go through and clear our seams so i'll select these edges here and we don't actually have clear seam over here in our context menu so we'll go to our uv and we have marked seam and clear seam i'll right click and add that to my quick favorites right click there we go and i'll take this edge hit q and clear seam so now we've just created two little boxes there i'll take this one right click clear seam now we have three boxes and let's do that one more time cue clear seam and now we've just stitched all these back together so now lastly what we need to do is just stitch some of these sides back together so let's just choose this one cue clear seam and let's do that same thing on the other side and the other box will just rotate automatically and you know get stitched right back into place and there we go so this works even on more complex objects another way to think about things is think about it as a cylinder so instead of thinking about this as a cube i'll go through and clear all those seams again i'll just separate out the top and then one of the sides so i'll separate out the whole top here right click mark seam and i'll separate out the whole bottom just like that right click mark seam and then just split it like i would a cylinder right up the side just like so and then to make this more of a t shape i'll go through and just combine some of these back together i'll take those vertices q and clear seam same thing on this side take those vertices q and clear seam and then we have a great t shape now like i said before we often want to have as few islands as possible especially if we have a large object with lots of pieces and we're going to have lots of islands no matter what then we want to minimize the amount just so that we can waste as least space as possible due to padding but if we just have you know a couple objects or a couple islands then it might make sense to break them up into multiple islands just so that we can pack it better and make better use of our texture space because here we have you know one really big piece but we could definitely get a lot more use of our texture space if we split it out let's say like this so if we take out this edge here q and mark seam then we can scale both of these up you can scale this one up pretty big move that off to the side and pack this one over here you know this is probably the best pack that we're gonna get of course we have to turn off sync selection in order to move just one island by itself you know then we're able to get a little bit more space out of our textures and just like we straightened everything out at the beginning we want to try to keep things as horizontal or vertical as possible because if we skew it like this then of course we're not going to be able to draw straight lines on our object now let's go back to the pot that we were working with before i'll go ahead and delete this cube alt h to unhide let's say we were finished with this and this was you know our entire object and we wanted to finalize it and pack it and get it ready for texturing well what we want to do then is unpin this so that we can actually pack it back in to the rest of the texture but we have to be really careful here because we still have live unwrap turned on and if we make any seam then we can just undo all of our hard work so i want to be really careful to turn live unwrap off after we're done unwrapping and before we unpin everything so let's go over here let's go to our uv options and turn live unwrap off just to be safe and then i can go through hit alt p and unpin and since we've unwrapped things while things were pinned and it kind of ignored those pinned areas what i'd want to do is go to uv and average islands scale and that way we have even textile density over all of our islands then i could go to uv and pack islands that's going to keep our nice straight islands but pack everything into one texture now if we do this for a bunch of objects all at once like we did at the end of pothead i'll let slash to exit local view what we did essentially was just go to edit mode for all of our objects not the eyes because those are not unwrapped but if we select everything else and hit tab to go into edit mode you know we can go to edit mode for all of these objects and unwrap them and pack them all at the same time so i could go to uv and pack islands just like so but of course we uh let's see that has a ton of margin so i'll set that back to like .01 there we go we're going to get a reasonable unwrap but it's not going to be quite as good as i would like first thing before we go through and actually pack things we did the average island scale to make sure that everything has even textual density but i don't always want things to have even textual density sometimes i want things to have more resolution or other resolution than other parts of the object for example if i want to take his face here i probably want to have a little bit more detail than the rest of his body so i'll ctrl l and select some of these islands here i'll make sure sync selection is turned off so i'm not accidentally grabbing other vertices of other islands and i'll just scale them up just a little bit i'll do the same thing for other areas like his hands here i'll ctrl l and select that and just scale that up just a little bit just so we have more pixels to work with in that area then for some areas i probably want to have less pixel density there so i'll select part of the inside of his face that's just going to be colored pure black and just scale that down and we can go through over the entire object and do the same thing and then once we're ready to pack select everything uv and pack islands but this is not going to be quite as efficient because blender's internal packing unfortunately doesn't really respect concave areas and so it's just going to use the bounding box of the island in order to figure out how it should pack things so i like to use external packers i like to use uv pack master too but there are a couple different options and one that's free as well i forget the name of it offhand but i can put it in the link in the description below if you'd like but once i have everything ready then i'll just go ahead and click pack just like so and there we get a much better result you can see it's all much more densely packed and we can also set a specific pixel margin and things like that so those are all the uv unwrapping tips that i have for this video there's quite a few so if you found any that were particularly helpful let me know in the comments below and if you want to go through the step-by-step creation of this character then the pod head course will also be linked to in the description so thanks so much for watching i'll see in the next one you

Channel: CG Cookie

Views: 105,974

Keywords: Blender tutorial, learn blender, CG Cookie, blender beginner, Essential Blender Tips, blender uv unwrapping, uv unwrapping, UV Unwrapping Subdivision Surfaces, UV unwrapping workflow in Blender

Id: 8qv6DbWr6zw

Length: 26min 34sec (1594 seconds)

Published: Tue Nov 09 2021