When NOT to use creases in Blender - Loops vs. Bevels vs. Creases when Subdiv Modeling

i'm in the middle of recording a course on how to model and texture this character in blender his name is pothead and the concept comes from our old co-worker tim von ruden and it makes for a really interesting challenge to translate into 3d because a lot of it is very sharp hard surface kind of machined type details but we also need a lot of organic type curves and smoothness so in the course we go through the subdiv workflow to get the best of both worlds but one of the things that's always coming up is sharpening up some of these edges and one of the things that a lot of beginners have questions on is the difference between using creases and using extra edge loops when working with subdivision surfaces i'm jonathan lampell with cgcookie.com and in this video i want to clear up the differences between the two and when to use each for that i'm going to go ahead and hide our character for now and turn on just this super simple example let's add a subdiv modifier to it just by hitting control and two that's going to give us a nice blob like shape and the first way that we're going to do this is just to add some edge loops but before we do that i'm going to just hit shift d and move this over on the x-axis so we can compare this to the creased version later then i'll select our original one hit tab to enter edit mode and i can just start sharpening this up with edge loops so i'll hit ctrl r and slide a loop over to the left ctrl r slide a loop over to the right and continue sharpening this up just like so so this is the traditional way of sharpening up edges in a subdiv workflow if i add one to the bottom i'm going to want to hit e for even and then f to flip to make sure that it's completely flat and same thing with the top one here once i add this in i'll hit e for even f to flip and that way it's not being pulled downwards now for this middle one or really any other edge that i want to add and holding edge on both sides what i could do is just hit ctrl b and bevel this scroll up once on the mouse wheel and that will allow me to do the same thing but much faster now if you do this though you're going to want to turn the shape all the way up to 1 so that the original edge isn't moved otherwise it's going to be blended down and you're going to get the wrong shape so with that i'll hit tab to go back to object mode right click and shade smooth and we can see that we get a great result with this now let's compare this to using creases i'll take this second one move it a little bit over hit tab go into edit mode and to create something we just need to take some edges here and let's select all the ones that we want to be sharp and hit shift e and drag our mouse wheel to the right if we drag it all the way to one it's going to pop up and be completely sharp but i'll leave it just a little bit shy of that we can also see this number if we hit n to go to our sidebar go to transform and under mean crease mean in this case meaning the average crease of all the selected edges we can also adjust it right here if we tab to go into object mode right click and shade smooth you can see that this one looks far far worse than the other one of course it's also using a little bit less geometry if we go into wireframe view and turn off optimal display for both of these then you can see the one on the left is indeed using a lot more geometry than the one on the right but not significantly more and that's the important part but let's for a second take a closer look at what this crease is doing in wireframe view so if we look at our subdivided wires here as i increase the crease it's just taking the edges that are closest to our original edges and then everything else is just blended in between those so the reason this looks really bad when it comes to our shading is that the way the smooth shading works is that it averages between our faces so as you can see here we have one face pointing in this direction and one face pointing in this direction with a really sharp edge between the two and that's a lot to average between even if we decrease the crease slightly and pull it back down to let's say 0.6 or 0.75 we're still getting a really sharp angle here that it has to blend between and that's just too extreme for it to look good whereas with the other mesh over here since we have a lot more faces to work with you know it's just averaging this face and it has this one that are pointing in those same directions now we also have all these faces in between that it can easily blend between and this makes for a much smoother gradation between the two surfaces as you can see in solid view the more subdiv levels we have the better this is going to look because the more geometry there is to average between but with the first example we don't really need that many levels of subdiv before it looks really good we need maybe three at most but we could probably get away with even one or two depending on how close the viewer is to this object whereas with this second one we have to crank this up quite a bit in order for this to look even decent so i'll take the mean crease and i'll pull it up to about 0.83 for our creased object and let's say we have our viewport level set to about five because that's where the visual quality is at least similar to this one on the left and even so we're still getting a lot of blending here at the top so we might want to try to crease this edge as well but we're gonna have to use a pretty light touch here otherwise it gets pretty crazy and pulls all the way to that point which we definitely don't want so i'll pull this in a little bit but not too much and you can see that these now look fairly similar so this one is still being pinched kind of inwards down here because of that so we're getting more visual artifacts here but even so this is still pretty similar but the big advantage of using a crease in the first place was that it used fewer polygons well now this is actually using way more and i'll show you the difference if i add a new collection here and drag this into the new collection and i'll turn it off so now we're just looking at just this object here and the one with the subdiv of level two we now have about 3600 triangles so not bad especially for a subdiv object now if we turn this off and turn on the other one the one that's visually similar while using creases we are now seeing 36 800 triangles so an exponential amount more for the same visual result and that's why i generally suggest people use the holding edges method instead of using creases at least for most things but i will actually use creases sometimes when we're working with smaller details so let's say we have this object here which is you know one of our main objects but we have just a little tiny detail off to the side of it and that can be this object so if i scale this really far down and just move this off to the side maybe it's just a little decal or something then of course we don't need this much topology in fact we can turn this down quite a bit i'll set it back to its original level of two and we can really start to see this uh crease being pulled up here so i'll uncrease that really quick shift e actually let's just set this to zero there to make it a little bit easier okay so it doesn't look perfect but if we're looking at it from you know this distance then that will still do and it'll use a lot less geometry than before now the point can be argued though that if we're going to be this small and it's going to be you know this less important then we may as well not use a subdiv at all we may as well just go through and take all these edges i'll hit shift g and select everything that has a similar crease and by the way that shift g hotkey for selecting similar of any attribute is incredibly helpful but let's select everything that has a crease here and i'll just turn the crease down to zero and instead hit ctrl b and bevel it instead i'll turn the shape down a little bit this time and now we're going to get a very similar visual result but for even fewer polygons than using the creases so i will still use creases sometimes and you'll see me do that in the course but it's in the very fine line between something that's really important and very large and something that we're going to get close to and something that's so small that we may as well not use subdiv at all now the one downside of using this approach of adding in all these edge loops is that it becomes kind of cumbersome to change our object for example if we wanted to make this peak a little bit more pointy then we can't just select this edge loop up here or even all of these let's just select all these vertices you know we can pull it up and make it more pointy but then we also have to go in and select these edge loops and pull them down a little bit in order to match that angle and so on and so forth and that gets very cumbersome so one thing that we could do is use a bevel modifier before we use our subdiv modifier i'll go ahead and hit shift d and just move this off to the other side and just remove all of these edge loops that i've added really quick that way we're back to our regular blob shape and instead of adding our edge loops in edit mode i'll just add modifier and add a bevel and drag that above the subdiv now i'll turn off the sub div temporarily so we can actually see how wide the bevel is and i'll turn the size down until it's about the same size as where we placed those edges before but just like before we're going to have to add one more segment here to keep that original edge and then go down to profile and turn the shape up to 1. then we can turn our subdiv back on and we'll get the exact same result over here but it's going to be a lot easier to edit for example we can change the sharpness of this over here under the amount and we can also control the sharpness in edit mode by using the bevel weights so instead of using the limit method angle over here i'll just set this to weight which by default every edge has a weight of zero but i'll just select the edges that we need to be sharp here and turn up the mean bevel weight and then if we need any edge to be even sharper then we can just decrease the bevel weight like so i'd also like to point out that using holding edges and using creases don't have to be mutually exclusive for example over here when we're using those holding edges if we wanted to sharpen up this top portion just a little bit more then we could select these edges here and turn up the crease so probably won't look as good as if we had just taken these edges and just slid them upwards but if you need your edges to stay where they are and need a little bit of extra sharpness then that's a good way to go the last thing i want to say on this subject is that you have to be really careful when you're doing the bevel before the subdiv method because it can mess with your uvs pretty substantially so here's what i mean if we go in here and let's say we wanted to add a seam at all the edges that are beveled i can just hit shift g and select those beveled edges actually i'll select two because that one has a different bevel weight shift g and bevel there we go let's say we want to just right click and mark seam and let's say everything just works out perfectly well everything is nice but if we go ahead and apply our bevel now ctrl a and apply for that modifier tap into edit mode you'll now see that our seams are entirely in the wrong place so by adding in these manually we get a lot more control but also we can set our seams exactly where we want them to be now it's not always a problem when it comes to unwrapping to have a bevel modifier here but a lot of the time it does cause more problems than it's worth but i'll show you how to fix the most common ones so you don't always have to apply this i'll just go over to my uv editing workspace here and i have a regular checkerboard image let's go ahead and apply it to the material for this object here i'll just drag and drop that data block right in that'll add an image texture of this and i don't even need to plug it in just because my solid view is set to texture and this node is selected okay so now we can see this this is unwrapped i'll just hit u and unwrap here increase the margin a little bit and you'll see a ton of stretching right along these edges now the first thing that we have to do to fix this and i talk about this a lot in the course is go down to the subdiv modifier under advanced and under uv smooth just change this to keep corners so that'll fix the initial issue and this is going to look a lot better now remember i said that we had to increase the segments so that there's an edge on either side if we look at our subdiv modifier here we can see that we have our original edge we have one edge kind of on the right one edge on the left but if we were to decrease this and let's say we only have one segment and that original edge no longer exists then we're gonna get a lot of texture stretching now it's not particularly bad here but when we add in our subdiv then things get even worse so it's something to be really careful of and the same thing applies anytime we have an odd number of edges here so if we go back to two then everything looks great but if we go to three then things start to look very stretched again especially in these corners here you can see we are starting to get a lot of problems but then if i increase this to four then everything looks good so generally i like to take this and leave it at two but i'll usually actually apply this before adding my seams doing all my unwrapping that way i don't have to worry about running into problems later and especially if i need to apply this later then again i still have all of my seams in the wrong place and if i go to you and unwrap then we just get a giant disaster so that's just something to be careful of when using this method but otherwise it's a great way to keep your mesh very editable and very flexible while you're still modeling i'll be wrapping up this hard surface character course pretty shortly so be on the lookout for that coming soon it involves creating a lot of complex shapes with subdivision surfaces like the holes in his little pot hat and the eyes in his face here all these things that we need areas where they're very very smooth but also very sharp and using holding edges and creases will definitely help us along the way we'll also be covering bevels and booleans and how to combine it all together so i'm really excited to publish that later next month so thanks for watching i'll see you then [Music] you

Channel: CG Cookie

Views: 69,343

Keywords: Blender tutorial, learn blender, CG Cookie, blender beginner, edge loop, edge loop blender, blender beginner tutorial 2.9, blender tutorial 2021, edge loop cut blender

Id: R9g7Fmrc900

Length: 13min 12sec (792 seconds)

Published: Tue Sep 14 2021