Normal map low poly artifact

HAWK12HT

issue relating to smoothing group both in toolbag and painter. If I split the UVs and assign sg accordingly the issue goes away however after that I get AA issue in normal bake on the curved areas.

I will be trying to add some more geo on low poly to ease the areas of extreme curve on model.

Ghogiel

Probably the prefered method to address that is using more geo in a way that minimises the harsh shading differences between the high and low.

More resolution in the map will help as well as making sure everything is synced, but that's almost never an option. Working on 4k maps is probably the current limit to any one texture set in substance unless you have a rocketship PC. So if that's not enough, it's mostly a case of, eh, it'll have to do.

Sidenote: You could, maybe even should, change some of the triangulation. Which will change the way it shades and the pixels that get rendered in the normal.

FrankPolygon

@HAWK12HT Would you mind uploading the low poly and high poly for just that component? I'd like to take a look at how it bakes in Toolbag.

Here's the result of the baking tests: (All tests use an 8bit 2k texture and 4x sampling.)

Adjusting the triangulation to remove the long thin triangles and adding a few vertices alongside of the raised feature reduced the amount of normal gradation and visible artifacts. Adding an edge split at the base of the raised feature also removed most of the normal gradation and visible artifacts.

There's some minor artifacts that remain in both of these but given the scale of the object and the addition of high frequency normal details this is probably good enough. Simplifying some of the geometry and softening or exaggerating the raised feature could help further reduce normal issues.

Adding additional support loops reduced the normal gradation but increased the number of visible artifacts along the triangulated edges of the low poly. Adding another hard edge and UV split along the top of the raised area further reduced the gradation and removed most of the visible normal artifacts.

If there's a technical requirement for minimal mesh splits and contiguous UV layouts then adding some geometry to even out the smoothing behavior and increasing the texture size to 4k will resolve most of baking artifacts and the high frequency details in the normal textures should cover the rest.

Face weighted normals would be another option that reduces normal gradation and artifacts while maintaining a contiguous UV layout with adding extra geometry.

HAWK12HT

@Ghogiel I tried to do the triangulation thing not worked, I even manually connected the verts to avoid this shading issue it was still same just artifact direction got changed in relation to where the new edges were on low poly. Based on that I am assuming I better add more geo support loops to control my low poly shading behavior. 


@FrankPolygonhttps://drive.google.com/drive/folders/1NB6ys26XMyoOTGhd3AfGvOGWd03TDW2p?usp=sharing  

Thank you all

btw I re visited this gem, turns out more geo support loop is the way for now however I could be wrong and well wondering what if there is a hard tech requirement that limit me from adding more geo how will one solve this issue then?   I get that since smoothing groups are impacting the vert normals thus causing this artifact but the surface is pretty flat so it should not do it... 

https://www.youtube.com/watch?v=ciXTyOOnBZQ&t=2s

Kanni3d

My best guess is simply because that detail is one smoothing group along with the rest of the spoon, and has a bit of a harsh angle change. If you take a look at your baked map, you'll likely see a lot of drastic gradients in that area of the normal map, and because of your low poly being smoothed like that, the normal map is forced to do a lot of heavy lifting. With those harsh gradients, you'll tend to see it along your triangulation as well.


Adding more geometry around the angle transitions can help, as it'll minimize how the shading is on your lowpoly, thus giving you a nicer normal map bake with less gradients - but you could outweigh the costs of that via just splitting the uv's with a hard edge, plus given the fact that this is such a small detail, it wouldn't warrant adding several loops worth of lots of triangles to fix that issue.

Regardless of that detail being 'flat' or not, it'll still get harsh gradients because it's got a steep angle change and being smoothed as one. Either choosing the split the UV's on the green border, or blue border, you'll see improvements, and even more so if you split both of them so it becomes three seperate UV faces.



Try breaking off those UV's shells from the main spoon, and giving it hard edges. Should bake a lot nicer


Edit: Didn't notice your files at first - here's how it bakes with those adjustments

HAWK12HT

@Kanni3d Hey thank you, yup there are too many artifacts along that curve above the extruded details slightly visible in first pic.
Well actually I did this way earlier sorry didnt mention when making this post, the reason I did not continue with uv split is because I want to keep texture seamless be able to stamp unique logo for example on this area. Hope this make sense, this leave me with only option for adding geo or is there something I am missing?    

Ghogiel

If that's the only reason you need to keep it one smoothing group, painter won't have a problem painting just about anything, including using the projecition tool, across UV seams.

Kanni3d

@HAWK12HT
Yeah, as Ghogiel mentioned, there's loads of projection tools/brushes in painter that'll paint across seams. Really the only issue with uv seams and splits is when you tile procedurals/tileable textures. Even those issues could be mitigated and/or painted out

HAWK12HT

@Ghogiel what about those smart mats and masks? layers of scratches dust etc I think those still get broken based on UV splits?

HAWK12HT

Thank you @Kanni3d @Ghogiel @FrankPolygon

I am going with Kanni3d's suggestion as its a small asset and not worth loops unless its a tech requirement that low poly shading must be like in game car model. 

CheeseOnToast

HAWK12HT said:

@Ghogiel what about those smart mats and masks? layers of scratches dust etc I think those still get broken based on UV splits?

Just change the mode from UVs to Tri-planar projection for any tiling masks etc.

HAWK12HT

Thank you @CheeseOnToast I keep forgetting painter stuff, I defi check it out. I did notice that we add too many layers of mat definition that these tiny artifacts just disappear or not so visible but its always good to know how to get clean results.

I wonder how much is allowed to be ok when it comes to bake artifacts especially on curves, you know those tiny mismatches even on a adequately enough edges 12+ for circles / curves. If you go super hard on highpoly you lose depth at distance aa issues etc. too soft and you get some ray issues even if your low and high are exactly 1:1 in edge flow.