Measurement and Geometry
In the real world we deal with three-dimensional objects. When we represent these objects in drawings, we are able to work in only two dimensions. Real objects can be viewed from many different directions and look quite different when viewed from each direction, so this poses a problem when working in two dimensions. If a viewer looks at an object from three different directions, an understanding of the object is achieved. A drawing on paper, on the other hand, can represent these objects only as viewed from one particular direction.
Artists mastered the techniques of perspective, that which makes objects in paintings look three-dimensional, only 500 years ago. This development can be observed by viewing Byzantine art and then viewing Renaissance paintings by artists such as Raphael. His 1510 painting 'School of Athens' clearly demonstrates this new-found skill.
Battistero Neoniano (451–475), Ravenna, Italy.
Source: Art History Images (Holly Hayes).https://www.flickr.com/photos/sacred_destinations/3262726344/sizes/m/in/photostream/
Licensed under a Creative Commons Attribution-NonCommercial 2.0 Generic licence.
The School of Athens (1509–1510) by Raphael.
Source: Wikimedia commons. Public domain image.
The skill of being able to draw some simple three-dimensional shapes is an important one for students to master.