Lines in Smooth Shaded cone

I am getting lines in a Smooth Shaded cone, I don’t remember having this problem before.

There are no duplicate vertices, I have supporting geometry, face normals are the facing the right way, Edge Split modifier doesn’t change anything, and this also happens if I just add a standard Cone Primitive.

The lines appear in Unity too.

(Using 2.92, iMac 2017 27", Radeon Pro 580 8 GB)

Could you provide a blend file? This way it’s complicated to help.

Did you look if your model have any custom geometry data? It’s common that models you download from internet have this kind of problem due to this custom geometry data. If you delete all that the problem disappears.

Anyway, I cannot be sure that that is the problem without seeing the file.

Yep, sure. This file is not downloaded from the internet. I made it.

Is just zipped okay?

Cone_shading.blend.zip (105.9 KB)

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Perfect. Let’s see.

It seems that lowpoly cones are not well handled by the viewport. I created other objects with the same specs and the problem is also there.

I will see if other versions of blender have the same problem.

Thanks for checking this @Calandro

I haven’t used Blender for about 6 months so I can remember if I last used 2.83 or 2.9?

You are welcome. So far, I saw that Blender 2.79 has the same behavior.

Is it just the viewport? - as I see the issue in Unity (2020)

But as you say, you can see the same result in your version of 2.79.

I have found this discussion that refers to that problem.

Thanks for looking into this. I tried the technique in the link but the result is still the same.

I never had a problem with this as far as I can remember, I always used to get a good result with Auto Smooth Angle, and add sharp edges if I needed.

Thanks again.

Yes, normally those techniques work just fine, but it seems that cones are shapes not well handled if they are low poly.

I believe that the biggest problem is that the faces are too stretched, not even close to squares, what is not really a big problem in cylinders because they don’t get thinner on one side besides the stretched faces.

If you make loop cuts to approximate the faces to squares it becomes much better, but it will not be low poly anymore.

Adding one or two extra loops in the upper / thinner part of the cone helped.

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Nice! I’m glad you have found the solution.

Sidenote: In reality those traffic cones usually does have a hole in the tip. So just modelling it wouldn’t raise the smoothing problem :wink: .

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