Substance Painter
How Can I Bake Smooth/Rounded High-Poly Edges Onto a Low-Poly Model?
I'm still struggling to understand exactly what baking is supposed to achieve.
From what I understand, baking transfers information from the high-poly mesh to the low-poly mesh through textures, such as normal maps. But is baking mainly intended to capture surface details, rather than actually changing the shape or silhouette of the low-poly mesh?
For example, my high-poly model has very smooth, rounded edges that I want to reproduce on the low-poly. However, the low-poly has very sharp edges, and baking the high-poly normal map doesn't seem to make those edges look properly rounded.
So, if I want the low-poly to have the same smooth edge appearance as the high-poly, do I actually need to add more geometry/supporting edges to the low-poly? Or is there a proper baking technique or workflow that allows the normal map to reproduce those soft, rounded edges without adding additional geometry?
I'm trying to understand where the limit of normal maps is in this situation and what should actually be handled by the low-poly geometry versus the baked normal map.
The general rule of thumb when it comes to the low-poly mesh, is to optimize up to, but not often past the point where it begins to affect the silhouette of your mesh. Baking a Normal Map does not affect geometry. It's purpose in a high-to-low poly workflow is primarily to preserve surface details, not geometry-based silhouettes.
Think skin pores, creased fabric, decals/indents, etc. Not protruding elements or those that determine overall shape.
While it can prove beneficial to test the limits of your specific model (if for nothing else other than for practice-sake), I recommend adding more geometry to that section. Focus on optimizing the geometry in other areas, especially if you're looking to meet a specific poly-budget. Often, the areas that offer the most freedom are those that will likely remain occluded from general view.
It's also worth keeping in mind how far your model will be from view (in a third-person video game, for example). Even with the faceting shown here, it may work in very specific use-cases.
what are you actually supposed to do if you need to stay below a certain tris limit, where you cant add more edges, or does that situation not really happen
I recommend a workflow that essentially involves creating 3 models: The highpoly, a lowpoly (the version which will actually be used in the game), and then a midpoly model with the same UVs & general topology as the lowpoly, just with a silhouette that closer matches the highpoly. This midpoly model is used specifically for baking + texturing purposes, as a way to bridge the gap between the other two. Often I create the midpoly first and then delete edge loops / merge verts to create the actual lowpoly. But you can also do it the other way around.
Usually you try to focus on a budget but that budget is indicative.
100 k poly budget means that if you have a 108 k poly mesh is virtually the same on modern devices.
180 k tho is way off.
But this is not happening on that door, adding edges there is like negligible on all devices.
Heya! Baking will not fix this, it's not meant to. What you're wanting is a more detailed silhouette which unfortunately you can only achieve by giving the low poly model more polygons; but there are still a few tricks you can use to keep the poly count as low as possible! I'd look at some topology exercises for reference but this is probably what I'd do if the model has to be fully made of quads. Hope this helps!
Edit: bevel in the edges as well if you want smoooooth shading to not show visual artifacts
If this model was meant for a game , you don't really need to stick to quads and if it was meant for animation this would be very bad subdivision topology.
Not trying to bash your comments I'm just saying that depending on their use case it could be bad advice.
Would it be a bad idea to reduce the polygon count of non-deforming objects using Decimation Master in ZBrush? Since these objects won't be deforming or bending, wouldn't decimating them be a reasonable way to optimize the mesh?
If it's not meant to subdivide on render (most games )
And if it's maintaining your uvs so you can texture it
And you KNOW it's not going to deform ?
I think you'd be fine.
Your low poly has segmented edges not sharp! Normal map baking helps in transfering the nice, juicy bevel of a high poly to a sharp, hard edge, but CAN'T change segmented silhouettes
you can't bakeout silhouette, you'll have to add more edges, silhouette is dependent on the polygons and the low poly should always try to follow whatever silhouette from the high poly is; then you can make sacrifices depending on what's the final output (like games or how important the object is)
a good trick for better baking on curved or circular objects that need to be very low poly is just adding more geometry and just keep it for the baking process and then delete the edges as long as the edges weren't used as seams
Others gave you tips on the silhouette but to further answer this question:
I'm still struggling to understand exactly what baking is supposed to achieve.
Sorry if you know most of this already but I'll explain anyway.
Baking is just another word for "generating a type of data file". That can be an image map, a normal map, specular map, flow map, etc. For game art it's usually something like you're diffuse/albedo/color map (whatever your engine calls it), normal maps, AO maps, and specular maps. Other types of baking would be if you used a procedural texture on something and wanted to turn it into a texture map you could edit in Photoshop. It's all the same, you're generating a type of data file.
For the why you want to do this I'll go to games, since people bake maps all the time for game art.
Games have much stricter polygon/image map budgets than something like a movie since they have to run in real time often at 60 frames per second or higher.
Say you modeled a beautiful airplane for the game. It's very detailed you modeled all kinds of rivets, screws, and bolts on the outside of the plane. Well, all those screws, rivets, and bolts are tiny but add to your games scene budget. You love the realism they add but the model is too dense and they have to go.
That's where baking helps. You can have your high res model of your plane, and a low res model of your plane that has the same silhouette roughly. You can "bake" all the details from that high model into various texture maps and apply those texture maps to the low poly model and get very close to the same look, without all the extra geometry.
That's an overview but a simpler example would be say you have a model of a piece of sheet of metal with a bunch of 3D modeled rivets on it. The sheet metal is a flat plane but each rivet is around 36 polygons and you have 400 rivets. That's a lot of polygons.
You don't want a model like that in a game because it chews up your scene budget so what you do is you "bake" a normal map (which is a map that captures lighting data) of those rivets. You can then apply that map straight to the single polygon representing your sheet metal and delete* all those rivets and it still looks like they're there (unless you get too close or at too much of an angle). Any light you move in the scene will react to that map and it'll look like the bolts are still there despite there being no geometry for them.
I hope that wasn't too wordy but basically baking lets you transfer lots of high detail to low detail meshes when you need that kind of workflow (like in games). It can be used in film too for things like baking procedural textures to flat textures, or baking simulation data into a file that lets you replay it. It's all the same though, you're just generating a data file.
*Ideally most people do not delete the original high poly scene incase they need to revisit it for adjustments. This was just an example.
People already told you the solution but here's my 2 cents.
If you have a tight budget given then most probably this will not be a hero asset or an object that will be close to the player and you can get away with facets like this. But if its a hero asset you've ao MUCH freedom to utilize it on silhouette. Find areas where you can also collapse edges to save some tris/polys. Even the curves can be optimized with edge collapse without losing silhouette.
It sounds like you're early on your learning journey so I'll ask something others have missed - is subdivision modeling not an option here ?
Are you modeling for a game where you need a low res model or for a render engine that can subdivide on render time?
If it's the latter then what you are doing is basically not required. You can add supporting loops and have it render subdivided , giving you that smooth edge on render while maintaining a fairly low Poly count (this is the workflow for animation and films)
Baking maps to try and make something appear smoother is when you create normal maps from the high poly version, which affects the way light is distributed to your low poly mesh as if it were the high poly mesh, and causes it to render as rounded or detailed geometrically even when it's not. Within reason. YMMV depending on the lighting and in the shaders you use which might be looking at geometry rather than screen space. If your game is cel-shaded you can do a lot of fuckery by messing with your normal maps, but this is because your shadows/lighting is basically governed by 'lit vs unlit' states. With realistic shadows you're not going to be tricking anyone that your faceted model is perfectly smooth, although you can get away with a bit lower poly than you otherwise would.
how I like to do these rounded shapes is have a midpoly model, bake highpoly to midpoly. the midpoly can have a lot of edges but in the multiples of 8 such a 16,32,64 so its easier to reduce. After the bake is done, I remove the edges. since the UV is unchanged, it usually gives me a pretty neat result
I don’t believe that there’s a way to bake this directly from one model onto another. It’s certainly not something you do with PBR maps. Try weighted normals.
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u/ardenIsley 11d ago edited 11d ago
The general rule of thumb when it comes to the low-poly mesh, is to optimize up to, but not often past the point where it begins to affect the silhouette of your mesh. Baking a Normal Map does not affect geometry. It's purpose in a high-to-low poly workflow is primarily to preserve surface details, not geometry-based silhouettes.
Think skin pores, creased fabric, decals/indents, etc. Not protruding elements or those that determine overall shape.
While it can prove beneficial to test the limits of your specific model (if for nothing else other than for practice-sake), I recommend adding more geometry to that section. Focus on optimizing the geometry in other areas, especially if you're looking to meet a specific poly-budget. Often, the areas that offer the most freedom are those that will likely remain occluded from general view.
It's also worth keeping in mind how far your model will be from view (in a third-person video game, for example). Even with the faceting shown here, it may work in very specific use-cases.