The shape is not pronounced or accentuated enough. Because of this, there is a problem with the perception of volume.

There are two types of volumes: the solid, which refers to a mass that occupies a place in space, and the void, which is made up of several planes and contains space.

The drawing of the volume consists of representing the magnitude or scale of an object and the space that the object occupies. To get this we use modeling art. It means drawing gradients, shadows, and lights on the objects to simulate their volume, and to create the illusion of three-dimensionality.