High to Low Poly Workflow in 3D Modeling

hey everyone today we're going to cover the workflow for taking high poly sub d models and optimizing them down to low poly models i'll be using my for this demo but the concepts and workflows discussed here can be applied to any 3d software this video is part of a series on how to prepare real-time game-ready assets in a real production pipeline this video is focused on understanding optimization workflows and things to keep in mind when you want to bake high poly detail down to your low poly models as always a like subscribe and share is always appreciated as i continue to grow the content to this channel so with that let's get started all right so here we are in mine you can see that i have the subd model version of the grenade the smooth subdivided version of the grenade with two divisions and the low poly model and you can see that this is 61 tries 1 million tries and about 24 000 triangles and what i've done is also recorded the process of me optimizing this grenade live so i'm gonna narrate and kind of discuss some of those high level concepts towards the end of the video and in the first part of the video i'll just cover the overall key concepts for optimizing your models so one of the most important concepts for optimizing your models is to maintain your silhouette and the silhouette of your model right if i go up here to the editor here and say just use all lights i don't have any lights in my scenes you can see that it just turns everything black all right now you can also use the surface shader to do this now this what this allows us to do is focus a hundred percent on the silhouette so you can see here that you know looking at the sub d model and the one million triangle model and then the optimized version the silhouette is pretty much has been maintained throughout the entire optimization process okay so this allows us to maintain the overall form and allow it to look like the original model because once we start optimizing for example if we take this now and i start to just remove the edges that are running along the the main part of the mesh this is where things start to to become damaging right now you can start to see this more noticeable hard corner here and the silhouette has been negatively affected okay now there's also a fine line between kind of pushing optimization even further so you can see i can maybe take every other edge at this point and it still holds up pretty well right and context also matters which brings me to the next concept which is have a target triangle count in mind you can see that here i started with 61 000 triangles and this was meant to be subdivided right so if i go ahead you can see that there's all sorts of good even flow of edge distribution on the model i've covered modeling this grenade from scratch in some of my time lapses and previous videos so make sure to check those out if you're interested in how i've created this so you'll see how this is all set up and then once it's subdivided you can see that we have about 1 million tries here now the key here is to take this subdivided detail and bake it down to the low poly model well for the low poly model we don't need to have all of those edges in here and holding lines and and bevels right we can keep some bevels and remove them right so knowing that knowing that i essentially want to take this to roughly about a quarter or maybe a a third a little bit over a third in optimization right so i'm at 24 000 triangles and then this is 60 000 right now i created this for you know i as a hero asset a hero uh grenade right so meaning that you're going to look at this grenade if i turn on the resolution gate and gate mask you can see that pretty much we're going to be looking at this grenade um focused in on this much there'll be a couple shots where i get in pretty close to about halfway where it'll take up a majority of the screen for sure now if this grenade was just kind of a secondary prop or tertiary prop and i didn't need all of that detail and it's only ever going to take maybe 15 10 of the screen that's where we can know all right well my target poly count can be much much less i went in here saying i want to be around 25 000 triangles if i get to 20 000 triangles great if i hit 30 i'll try to push out a little bit further and that is all kept in mind as i want this to be a hero asset and a focused prop okay now if this was again a lower poly prop or something that's in the background i can push it maybe down to 10 000 or even 5 000. it really depends on what the goal is so know what your goal is before going through and beginning your optimization process the next key concept is to of course leverage the base mesh where possible all right now in some instances if you saw one of my previous videos i showed how to take a high detailed sculpt and i showed rita paula's retopologizing concepts for that in this instance we have a sub d model that is ready to be subdivided and then we want to convert that into a real-time 3d model all right so because i have this here for example if i go ahead and just duplicate and unparent this with shift p and hit isolate you can see now i can go in and start removing some of that those holding lines and bevels that don't need to be here right i mean that was a big part of what i did on this model right i would say probably a good example was when i started to go through you know some of these assets here and i would say this is kind of the simplest example here you can see if i hit 3 go into smooth preview you can see that it subdivides very nicely but for the low poly model i don't need all of those holding lines since i'm going to bake it down well that's what i can simply go in here and start removing those bevels and all of these lines here to leverage this model and save me a lot of time all right so this kind of saves you time as you're modeling the original mesh and then when you're creating the base mesh so definitely leverage where you can and of course like you can start to even take it further and removing essentially all of these other lines that aren't really adding to the silhouette remember if this is the key silhouette here then these lines on the inside here don't need to be there right but clearly i need these lines and these edges here because that's where that matters i wouldn't want to go ahead and remove this one this edge here because this is a key line that is helping define the original form and silhouette and this would cause baking issues if i just outright deleted that right and then you can see if i grab turn on the lights again and take a look at the original mesh you can see what kind of problems that would cause as you can see here here's the optimized version and then this is the high poly version and you can see that if i were to take the low poly version now and remove this key edge here that's defining the silhouette that's going to cause a lot of issues and it's going to cause baking issues right you'll see that here if i go ahead and assign a different material to this something like this where we have kind of the green here on the low poly and then you can see kind of the difference that's causing so this is a technique that i use all the time is making sure that i have different and contrasting materials for the low poly and the high poly materials here all right so keep that in mind as you're going through and optimizing is to leverage the base mesh where possible all right so the next concept i wanted to bring up is especially when optimus doing optimization is triangles are completely fine so when i'm doing sub-d modeling even having an occasional triangle is completely fine right and there was a couple of joke comments about how it was like blasphemous and i can't believe that or i spent a big part of my career making sure that i never had triangles so did i you guys it's not a big deal right so just keep that in mind um because the algorithms for essentially subdividing these uh these triangles into quads is uh not an issue as much of an issue right you have to be careful don't go crazy with triangles but having an occasional one is completely fine so if i go ahead and subdivide that look what it did to that triangle right it went ahead and actually turned this into a quad which is okay right and i made sure that it's not artifacting either right so you can see if i look around here there is no visual visual visible artifact in here so why worry about changing that when i don't need to now if we take a look at using triangles for optimization you'll see that this model is full full of triangles all over the place and this is just going to help with the optimization process because i don't want to carry over edges that i simply don't need right and that that's a big part of the optimization process all right so make sure to use them where you need them like if i go ahead here you'll see that i just i just use them all over the place here to not run all of those triangles and edges throughout the uh you know the rest of the model that i just don't need them and i'm eliminating edges that are running horizontally the ones that are running vertically in different axes so it's just becoming very very optimized right so again if you take a look at what i had previously not this one the subd model here you'll see that if i take this duplicate it and we'll just go ahead and move this a little bit closer you can see just how much more optimized this is versus the original base mesh now because this is such a key part of the silhouette i didn't remove a lot of the edges running down the grenade but i certainly can and you can also see in areas like this right here that's where i cleaned up and removed a lot of the edges here and just kept them as triangles okay so triangles are completely fine are great for terminating edges that you know you don't need to run throughout the duration of the model and it just keeps things very clean and you can see here how i removed the holding lines and edges that i kind of talked about at the beginning where that's no longer needed for the low poly model all right but then the next thing is making sure that you add in geometry for your corners okay so what do i mean by that is if you take a look here and a lot of areas that are going to have kind of this uh softer radius if you just have this be very sharp so if i take this now and actually compare this with the subd model here and i'll go ahead and bring this over to this this should be about zero there we go now if i go ahead and compare this now this next tip again is about making sure to add geometry for your corners so again i'll go ahead i'll apply a different shader and let's take a look at the difference here right so we have this model and then if we take the original base mesh here and i move that you'll take a look at kind of the difference that's happening here and i'll go ahead and kind of isolate all of these all right so we have this part of the grenade here this is the optimized version and then this is the original subd model all right so let me compare the original subd model with the actual subdivided version of the grenade and then i'll change this to even a different color i'll change this to red so it's much more visible and look at that right this is going to subdivide fine and i got my holding lines to make sure that this sub divides nice and clean and nice and even evenly and it looks great but you can't simply just take that model and then try to bake this detail here into this corner it's just not gonna work i covered that in the last video on tips for baking high to low and you're just going to need to make sure to add in some of that geometry well that's why i did that right over here if i take the green one now and compare with the sub d model now look at the difference right take a look at now how i went in and cut in some extra edges that i needed just specifically in this area and it's going to just bake into that detail significantly significantly better okay so make sure to keep that in mind this was probably the best example for corners in some instances too it's okay to have you know these uh kind of corners here that are completely flat but if you have corners like these that have like this nice round radius having a very sharp corner i'm going to just quickly delete this and then i'll undo it if i remove that trying to bake this uh round corner into this is going to produce a lot of artifacts so that's why i want to make sure to have a good radius for our corners now again this depends on how low and what's your target poly count if your model can't afford it and you have to go extremely extremely low then you're just going to stick with this as your corner edge here and then baking that down you can still get by with doing that so just keep that in mind that on occasion these are just general guideline rules and don't think that this is you know the end-all be-all uh for as far as optimization but these are just general guidelines to to help okay now the next tip which is really really important is making sure to use what's called a shrink wrap which is really nice because there's something to keep in mind when working with sub d models is that a lot of times your models will lose volume when they're being subdivided so if i take this now and this is the sub d model so i'll just kind of hide that or get rid of that and then here's the low poly model that i duplicated and then you can see that if i wanted to take this and then smooth this or shrink wrap this on this surface you certainly can right so for example if i take uh you can do this on face selection so for example if i go ahead and select kind of these faces here and i'll go ahead and just do a shift period and go ahead and kind of grow that selection there and then we get something like this okay i don't want to do the insides because it's a separate piece but this is good because now i can take this these surfaces okay and then i can take the high poly version so now if i take this high poly version i'm going to have to manually select selected here so you'll see it's poly surface 92 so if i go back i have this and then i grab poly surface 92 this is where you can use the deform and use shrink wrap okay so if i grab this and these are the typically the settings that i use for shrink wrapping and what this is going to do is help make sure that it wraps on this mesh here so i typically use projection and these settings and then hit apply and take a look at that now it's gone ahead and wrapped itself around the mesh and there's this is going to be very very helpful there are a couple of areas that i do plan to go back and kind of cut in some detail to help with these corners here especially being kind of on this high visible part here so i do plan to fix that but at least you get the idea of how to use shrink wrap right and if i take this piece here again i can show you kind of as a quick example i think this was a good piece that i ended up using here so i'll duplicate this one and just show you quickly on an entire mesh point of view and i'll grab the two here and i'll assign the material here for the low poly so we have that with the low poly version and now what i can do is select the high poly select the low poly and if i can get that real quick so i'll just select it from my outliner here there we go so you want to select or excuse me it's the other way around low poly then your target mesh okay so again select your low poly then your target mesh that you want to shrink wrap on and then you can use deform shrink wrap and then hit apply and then that goes ahead and does it so i've already done that in this instance so i'll show you like a quick example of it kind of working so i'm just going to move these whole control middle mouse and just kind of move these out a little bit so it's a little bit larger and you can see by smooth previewing and mesh smoothing it does lose some volume so i can take this mesh this low poly version take the high poly and then now you can kind of see it especially right here on this part of the radius and hit apply boom look at that so now this low poly is pretty much one to one and it's uh i don't have to worry about it you know create any custom cages or anything it just fits the mesh okay in custom cages i mean for for baking that detail and that projection all right so shrink wrap is an incredibly useful technique i use all the time and i use it all over the mesh so definitely keep that in mind so along with using the base mesh and optimizing the base mesh uh with the combination of using shrink wrap i'll use another technique where sometimes if i just want to just completely rework the topology i will just use uh quadra quadra is just a fantastic tool for that actually this is what i did specifically in this area here if i go ahead and kind of delete this and for example i'll just stick with this and i'll select the high poly mesh and set it to live select my low poly mesh here and then go to the tool modeling toolkit and then enable quad draw and then now i can just start working off of this original mesh and start working off of the high poly model and eventually just start to just rebuild and have complete control over the topology here so it's just a very nice way quick way to do that um leveraging the high poly mesh you know i've covered how to use the quad draw tool set in one of my last videos with the dragon head so make sure to check that out um but yeah i mean this is just kind of a real quick high level uh workflow and then i cover that in the uh time lapse as well all right and the last thing i want to make sure to cover is make sure to review examples i mean i bring this up all the time in my videos and just study study professional study uh professional artists and and people instructors posting um so here i mean this one popped up the other day um or at least on my feed by yuji moon and he just has this fantastic model i was like wow this is this is just amazing and then i looked at the low poly cage i was like wow look at all of that detail that's being projected down on the low poly and he says here this hero model this entire hero model is 30 000 polygons all right and the key thing he he applied all of the principles i'm talking about here in this video which is if you take a look at this model he has made sure that the most important thing is maintained which is the silhouette of this model all right here the silhouette of the model is maintained and he's you know making sure that he knew the triangle count going in and he's using triangles all over the mesh which is again completely fine and then he's making sure to have more edges in those smooth corners so it bakes properly and you know probably using uh shrink wrap where where applicable so i mean it's just again a really really great example uh and just showing how you can do that throughout the mesh here's another example i found um by stanislav teslenko and i really liked his model here because he really high detail nice details but if you look at the base mesh the little poly i mean he's incredibly optimized here he also didn't have to use any bevels um or holding lines or anything like that everything's just baked nice and clean so it really depends on your target triangle count and you can see his just for this prop here it's again 30 000 triangles all right now keep in mind sometimes if people use the word polygons that you basically want to double it for triangles so this looks like 60 000 triangles and this is going to be about 30 000 triangles for this piece and uh here's another one for a character again the most important thing here is the the silhouette of the character right and this is by david bolton and you can see you know just very very nicely clean optimized good even flow distribution all of that good stuff and then again focusing on the silhouette and then i like this one by carol sung um where you can kind of see you know she's making sure that she's having all of that most of that detail in the most curve um the places that needed the most which is anywhere that has curvature and then you can see around kind of the base of the gun here uh and then she baked it from this fusion 360 model and you can just kind of see you know with a combination of using curvature where you need it and having triangles everything kind of comes together really really well so definitely look at some good examples there and then keep in mind in some areas i'll have kind of this beveled edge here okay so i'll keep kind of this supporting edge to help with baking or sometimes i just won't need it okay and there's a little bit of cleanup i have to do on the edges and stuff like that but i at least wanted to show you uh these this part now and you know i could maybe put a holding line i i did do it on a couple of more obvious areas so i did add some holding lines here but again if i needed to push the optimization even further i would just delete these edges and focus on using that all right but i wanted to keep kind of a mid-range higher poly count for this um and about 24 000 triangles um you know i felt like that that was accomplished so you can see that's faces typically it's going to be or faces are polygons here okay so that is these are the key concepts that i use to create this model so next what i'm going to do is go ahead and show you the time lapse and i'll just kind of explain uh that process and a little bit of a narration on the overall workflow and where i'm applying these principles all right so i'll see you guys there all right so here i am starting the optimization process and the first thing i did was cr duplicate it i always recommend duplicating your meshes applying a different material so that way you you know your files don't get corrupted and you'll be you'll be good to go i then went ahead since the insets were separate pieces i went ahead and uh removed any extrusions from there and then i'll eventually combine that back to the original mesh now i'm going through the process of removing all of the holding lines the extra subdivision lines for the even distribution for the sub-d modeling and i'm just out right just deleting them and removing them since it's not needed for the low poly in some instances i go back and add in some edges there just to kind of help maintain the original form and then here it's just a little bit of a tedious process going through over and over again for each one of these insets and cleaning up that topology so i basically go through the whole process on one or two of them and then i go ahead and just uh kind of show the the final product uh here i'm going back now and adding in some geometry to help with the curvature and cleaning up some of the bottom edges there and then now you can see i went ahead and combined it on the subd model now comes the important task of making sure that i'm matching the curvature having essentially just uh maybe two to three edges for that top curvature isn't helpful so i have to make sure that i cut in some more to be able to get the most out of my bakes so i went ahead and did this on a couple of these pieces here and i'm evenly spacing them out that's why i also have wireframe uh on edges showing or edge faces showing so i can see and get a more or a better looking distribution of edges here so i think i kept it around you know two to three edges edge span and then i went ahead and cleaned up kind of the bottom uh here yep i'm definitely using a lot of triangles here making sure that i keep you know things optimized and doing whatever i need to do i'm now working on the top piece here and this is where you want to make sure that you add that edge basically on the highest point of the corner to help with baking and then i go ahead and give this area a bevel here and then i'm just continuing on around the loop and this is why i do quite a bit of optimization so you can see how i'm just merging combining the leading edges all throughout this top piece which helped remove just a lot of a lot of detail that just wasn't needed since it was completely flat i go ahead and continue this through the front part of the grenade and now i'm working on this corner radius piece that i was talking about so i'm going in cutting in some of the edges and making sure that i have the geometry to support for uh when i'm going to bake that detail in so this is very very important that i cover in the early part of the video and you can see me putting it into practice here and then i go ahead and kind of show how i do that on the corner radius as well on the front part of the grenade just going in and cutting i actually ended up instead of cutting the bottom piece i just moved the other edge up since it helped maintain the original silhouette now this is the part where i switch to another piece and you can see that i'm beginning by just taking and removing all of the holding lines and edges and i do a little bit of cleanup and this is where i deleted that inner piece that inner inset and then i ended up just using quad draw there so go ahead and let that go through and then i kind of keep those corner pieces because it is a pretty wide round radius or wide radius for the corner so i kept that there and then here you can see i'm using you know switching between multi-cut quad quadra and just make sure everything's aligned up and cleaned up and then i'm just using the wire frame as well on the sub d model to make sure that i keep good even spans and distances between the edges so that'll ultimately help with the getting nicer clean bakes by the end of it and just some more cleanup here i decided that i wanted to keep the few edges there for that piece since it was such a focal point um and kind of an obvious piece on the the top portion of the grenade and just a little bit of cleanup here this is also why it's important to have good clean edge flow because it just makes your life easier down the road especially when you need to create an optimized version level the detail models or if you're unwrapping even wanting to take it to sculpt edgeful is just incredibly incredibly important for that and then just a little bit more cleanup and then you'll see me use once i'm done here um just finishing up the bottom piece yeah pretty shortly here yep i went ahead and shrink wrapped it so make sure to use that and then once i shrink wrapped it i just kind of finished it off and cleaned it up and then i went ahead and i'll be jumping to the next part in the next piece so there's about a few minutes left here uh and it's just doing the same thing over and over again so i think you guys get it i'm going to let the time lapse go and i just wanted to make sure to um thank you guys for for watching hopefully you found this helpful in the next part of the video i'll be sure to cover um the final cleanup stages of the model and then getting it ready and applying uvs all right so that was the main part of this one thanks for watching and i'll see you guys around all right if you stuck around for the end i really appreciate it hopefully you found this helpful and if you've got any suggestions let me know on anything that you want me to cover in a future video but again i'll be covering unwrapping and preparing the model for the final break in the next video so i'll see you guys there thanks a lot

Channel: On Mars 3D

Views: 57,657

Keywords: 3D, modeling, 3d art, autodesk, maya, topology, edgeflow, hardsurface, hard, surface, tips, workflow, speed, improve, intro, understand, understanding, edge, flow, basics, retopo, retopology, polygon, low, lo, poly, high, hi, sub, subd, sub-d, subdivision, baking, texture, best, mesh, triangles

Id: YDu9pYMkkSM

Length: 32min 1sec (1921 seconds)

Published: Sun Jun 06 2021