What is Normals?
Normals are important in 3D visualization for two main reasons: they give your models a sense of volume and they help to create the illusion of light and shadow.
In terms of volume, normals help to define the shape of an object by creating “faces” or flat surfaces. They also add depth and texture to models by making them appear three-dimensional.
As for light and shadow, normals play a role in how light reflects off of objects. By default, most software programs will render objects as if they were illuminated by a single light source from directly above. This can often look unnatural, especially for organic shapes.