How to deal with these pesky shading issues?

I know it’s been a subject as old as world, but never really understood how to make proper topology on some bits.

I used the unfamous destructive boolean modifier to cut through these part with a cylinder to make get that shape, and it creates shading issues I cannot get rid off, and obviously also after being textured…


What is your say on this ?

Thanks

Any feedback ? This shouldn’t be that uncomon is it ?

Hi, look at the topology its full of ngons and vertices that need to be merged. if you clean that topology (by having Quads only) all the shading issues will be fixed automatically.

Watch these videos from josh gambrell:

cheers :smiley:

Thanks for your reply,

I got that, but don’t really get how to got proper quads with nGons like this , even with the nice tutorials

I tried the knife tool trick, but always end up having that shading issue between these two superimposed faces …

The problem is, with the way you are doing it you are increasing your texile density in a very small concentrated area so nomatter how you do this you are going to have problems. I say this about bools all the time. the are cool, and they can work, and they don’t have NO place… but when I use them to make complex cuts on curved surfaces, I retopologize later for the exact reason of the problem you are having now. N-Gons are sorta nonos. Yes blender lets you make them, yes they work fine for flat surfaces (sometimes) but you can run into a plethora of problems with textures, shading, and more of the like. Tris are not really an issue anymore like they were in 2001, but they can still cause a lot of problems. Bring down the density of your cutouts, like, a lot, if you don’t want to retopologize, and then use the knife tool to fix it up after. 24 verts on one half of a cut is a LOT… I mean a LOOOT. Typically for a high polly model, I would use between 6 and 8 contact points, so a cilinder with between 12 and 16 verts, cor something like this. I can always upres later and I can get smoother transitions after subsurfacing because there are fewer vertices to screw up.

You will almost always wind up with some triangles somewhere. The trick is to put the triangles somewhere relatively flat where their shading issues will be minimized.

If you take the lower edge of the face highlighted in that picture and you extend that edge all the way around the object until it connects to the corresponding vert on the other side of the cylinder cut-out… and then do that for all of the rest of the edges, you might have much better shading but the geometry and work involved is crazy. Instead get a lot of quads in the vicinity of the detail and then taper those quads into triangles somewhere flat nearby.

I get that, in theory,

But for this - yet very easy machining action - , that would be a heartbeat in a CAD software, I really run out of talent very quickly …

Here is the .Blend if ever …

https://pasteall.org/blend/c67a4e9ca788461d8f888701b93793f9

You could try selecting the edges I’ve highlighted in red and mark them as sharp, then use auto smooth or use the edge-split modifier.

It’s not a substitute for cleaner topology but might be OK if you just want to show a hard edge.

Actually I also tried that, but the point was more about getting rid of those shading triangles squarred in red

Was this the file of your issue? Doesn’t appear to be the same.

It is the same I just let the cylinder that should remove matter, before any action, to show

I played around with this some. You can tweak some more if you want.

Test.zip (1.3 MB)

Wow that’s perfect, thanks !

So I should add edge loops basically

The problem is, blender isn’t cad. CAD uses curve surfaces which dont actually contain any geo. It is just a representation of how points connect, not an actual representation of geometry. Blender on the other hand is a modeling application. Meaning, your edgeflow needs to work. It just does. If it doesn’t then shading issues will haunt you in your sleep. My suggestion for complex hardsurface that needs to look like cad is, do it in cad and then retopologize. Saved me so many headaches trying to match physical items in the past to just use a cad file of the actual product and retopo it. If you want to go the hardsurface modeling route, which is the more common method because most people are not trying to match to a cad file, is to just clean up the topology like you see @AFWS did. And if you note. AFWS thinned down the geo more than he added loops. Yes holding edges are needed but look how they took the geo down from 24 points of intersection down significantly to increase control.