Normal Map Baking: Blender + Substance Painter

today we're going to look at picking the details from a high poly model like this down onto a low poly retopologized model and we're doing that through normal map making so the first thing that we want to do is um in object mode select our low poly model and make sure that it is shaded smooth so that we don't get all of these hard edges we're going to break down the edges from our high poly map so right click your model and go to shade smooth and that should smooth out all of those edges for start the next thing that we should do is rename our plane here that is our low poly remesh model to rock underscore low for low poly under high poly that's our ecosphere that we started with there and we're going to rename that to rock underscore high and blender doesn't actually carry those names across into the exports but it's just good to have your layers labeled so now to export both of these models we're going to do that individually so i'll select the rock low first of all i'm going to go to file and export and fbx and then i'm going to choose a name for that file the name should match the designation we give it here which is rock underscore low and we're going to use limit to selected objects it's very important so we're only exporting the object we have currently selected and then i'm going to detect bake animation because we have no animations on this anyway and then hit export fbx to your location and the next thing is to select that high poly model file export fbx and then again make sure selected object is on and this time the suffix is going to be underscore hi and that's all you need to do in blender over to substance painter we're going to file new and then select our file on the top right here and it's going to be the low poly model that we want to break the details down to that's our end result the in-game model that we're going to be using i'm going to turn this document resolution up to 2k and then hit ok now one thing that's important to point out is your low poly model should already be uv'd so if it isn't you should go back into blender or maya and uv that the high poly doesn't need to be uv it's going to be the details down onto this uv map so to do the normal baking process we're going to go edit bake mesh maps we're going to change this output size first of all to 2k to be higher resolution and then under the high poly parameters we're going to select the high definition mesh that sculpt that we made in blender so select it with a file icon in the top right there and select rock underscore high and go to open that now these file designations we've given underscore high and underscore low and you can set the match here to match by mesh name and you see that substance matter already has underscore low and underscore high as the suffixes on the end of those just so that it knows what's speaking down onto what we could say you had a human model and you were making different parts of the human you could actually name the different parts of the mesh it would make them individually to save the maps from overlapping and things the only other very important parameters for us right now are the max frontal distance and the max rear distance but we'll talk about those in a second so let's do a test bit by hitting big selected textures and this may take a minute or two depending on your um computer's ability once that's finished baking just hit okay and then take a wee look at your model and one thing that you'll notice here is there are some big errors in the bake and that is an error with the normal map specifically you can notice it here around the back of the model and here around the front of the model so let's take a look at what that is we've got some of the good details we have down in here but there's definitely some errors that we could clean up so if we select this little drop down we can scroll to the bottom and find our on our mesh maps our normal map that we make there and you can see that it's not actually computing normals for those areas that it's left out um let's take a look at why that is so back in blender here you can see that there's an air across the front of this model if i turn on the low poly we apologize model here and i just zoom around you can see that there's a bit of a high poly model that bulges out away from the loop poly and what's happening is whenever you're baking the normals it's basically automatically putting a little cage wrapped around this that it computes at a certain distance out from the surface of the loop poly and it's shooting down light particles and ray tracing basically and every time a ray hits a part of your high poly model some of those details it just zaps it down onto the surface of your low poly model so what's happening is our cage is cutting off parts of this high poly model so we can either expand the cage so that it takes in more details or what we could do is edit the low poly model so that there's another edge loop in here and then more closely stuck to the shape of the high poly it'd be much easier for us now to use those sliders in substance painter so that's what we're going to take a look at so in substance i'm going to go back into my edit and big mesh maps menu and underneath the max frontal distance there's a distance in front or outside the model that the big happens and there's also some bits clipping inside so that's the max rear distance so we'll change the max frontal distance up a wee bit change the max rear density up a wee bit try it back again and see if that captures all the details we need for this model this result looks a lot more promising if i take a look at the surface there's no parts that have been missed out from the model you can especially tell it from the uv map here and the details look like they break down really nicely even those cracks that we have on the top of the model there so all it took was changing the frontal and back distance of the cage and to encapsulate those details like the reason it doesn't automatically set that cage uh too high is because it imagines you have little details like screws that are being positioned into very specific areas the further away you move the cage the less accurate the rays that are being cast onto the model are going to be so ideally you want those sliders to be as low as possible sometimes there's a bit of trial and error into getting these as low as possible while getting the details correct but for now i think i'm happy with that so that's it for this model if i pop back into my material mode here you can see it's zooming around the model that the normal app is backed by correctly there doesn't seem to be any issues with the lighting i've got all these great details from my high poly um sculpt breakdown onto that very low poly model now let's take a quick look back at our reference image for this what i want is like a middle gray kind of tone for the majority of the rock and these light areas around the edge that make it look like edge wear let's create our own material from scratch in substance painter we're going to delete the default layer that we start with and create a fill layer and what if the layer will do is apply to the whole surface of the model so we're going to change that base color to a kind of slightly deeper gray color there you can see that this model is quite shiny from the lighting there and the rock wouldn't naturally be that shiny unless it was polished so we're going to increase the roughness here to make it look more like a stone surface so i'm going to have it above 50 anyway a metallic should be right down the bottom because there's no metalness on this you can see i have an opacity on the mr slider if you have anything like that you might want to turn those off let's go ahead and name that layer base and next we're going to create the edge where look so again we're going to create a fill layer that's going to fill the entire model we're going to choose a base color that's a bit lighter than it was before and we are going to go down to roughness and this i'm going to make it even rougher because i want the edges to look chalky like they've been hit off something so the next step is getting this layer to only show along the edges and what we're going to use is something called the curvature up which we baked when we make the mesh maps you can see it here and the curvature map detects the edges of your high poly model during the baking or the low poly model if you just bake it normally so i'll go back in the material view and what we want to do is add a black mask first of all to this layer i'm going to rename this layer just so you know what it is it's edges and this black mask is completely painted out the fill layer so what we can do is we can um smart adjust this rather than painting along the edges which you could do but it would take you a while we're going to use what's called a generator so if you go under the little uh wand menu you see we can add a generator here and under the generator options we can choose that curvature map and what that will allow us to do is use the curvature map on the black mask the next part is easy we've got a bunch of settings here in the properties panel and we can change the blur of the mask we can change the global balance of that curvature map for where the edges are going to render up and we can also change the contrast to be higher or lower depending on how stylized we want this to look so i quite like the effect that we've got going on here one thing i don't like is the way it's calculated the edges of the crack here it just looks a bit weird with the edge where so what i can do is edit this black mask by selecting it adding another little wand tool here i'm going to add paint and then with that paint selected i can simply edit this this map but at the moment it's painting white if i press x you'll see this little circle on the right the sphere turns black and that means i'm painting black okay just changes the color of your brush so i'm going to paint black over there just so that that little crevice kind of stays dark and any of these other areas i want the kind of light paint out to clean up the edges i can do that now so you could add more generators to create moss to create dirt to create all sorts of things on this material just by creating a new fill layer adding a black mask and then messing around with other generators there but for now i'm pretty happy with how this render looks and the lighting is playing nicely off the surface so that's it we've baked the details of the high poly down to the low poly and we've created a custom material for this rock and it's not a game-ready asset that's good to be imported into unity

Channel: Jonny Shields

Views: 15,301

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Id: 8Q7zHNK1ByA

Length: 7min 15sec (435 seconds)

Published: Mon Feb 28 2022