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I am curious about how to apply the shade smooth value applied to the faces around that face to some faces that do not have shade smoothing applied, as shown in the image.enter image description here

I tried applying Shade Smooth to the angled face, but it doesn't connect as naturally as in the image. Can I copy the smooth normal data from the surrounding face and apply it to this angled face?enter image description here

How can these faces be naturally connected?enter image description here

Duarte Farrajota Ramos
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  • Hello, if you shade smooth again and it doesn't work it means that the topology tends to flattent the shading and you need to round it, you can try a Ctrl V > Smooth Vertices in Edit mode – moonboots Mar 13 '24 at 13:39
  • Try selecting this object and applying a smooth shading again. This may have happened because of the new geometry. – KISKAart Mar 13 '24 at 13:40
  • please share your object: https://blend-exchange.com/ – moonboots Mar 13 '24 at 15:27

2 Answers2

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If you are wondering how you can achieve smooth shading just for some of the faces: with the object shaded flat, go into Edit Mode to select some faces, then right-click and choose Shade Smooth (only available in Face Select mode).

If you then go back into Object Mode, the selected faces are now shaded smooth while the unselected faces stay shaded flat. Selecting a shading option in Object Mode afterwards will remove this face distinction and apply the same shading to all faces.

Of course it works the other way round as well, on a smooth shaded object you can set some faces to Shade Flat in Edit Mode. Note that the Shade Auto Smooth option is not available in Edit Mode (but you can enable it afterwards in the Object Data Properties and it will have an effect on the partially smoothed mesh).

faces shaded smooth

By the way, the Set Shade Smooth node in Geometry Nodes can also be set to just smooth a Selection of faces instead of all. Here is an example where I just smooth all faces with index > 120, as you can also see in the Spreadsheet (which by the way shows this information even when you set it manually without GN):

smooth selection in GN

Gordon Brinkmann
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Go to the Overlays and enable Face Orientation - the surface of the object should be blue. If some parts (the ones with the issue especially) appear red, go into Edit Mode, then select all with A, then press Shift+N to recalculate the normals. If there are still red faces, select them manually and press Alt+N > Flip (however the fact they did not change before might indicate there are more issues with your mesh).

face orientation

Another possible reason: go to the Object Data Properties tab and check under Geometry Data if there is a button that says Clear Custom Split Normals Data. If it exists, click on it and check and see if it helps. If the button says Add Custom Split Normals Data then there are no custom split normals and you should better not click it to add some.

custom split normals

Gordon Brinkmann
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