Shade Smooth to make it have a surface with no visible borders

between each face.

4.2.2 Fixing smoothing problems

In the process of smoothing 3D models, you might encounter a few

problems caused by unmatched face normals. Face normals are the

visible side of a 3D polygon, and depending on the tools and techniques

applied to create each object, you may have normals facing in opposite

directions.

For instance, if you look at the object in Figure 4.10, you see a dark spot

from the smoothing process.

Figure 4.10 - Object with dark spot

To view the difference between normals in that object, we can enable

the visualization of Face normals in the Overlays menu. That menu is

available on the left of your shading options at the 3D Viewport header

(Figure 4.11).