There has always been a connection between architecture and visualization. Not all visualization is about communicating data, sometimes visualizations show concepts. The core of what architects do is creating visuals that communicate complex concepts, processes and spaces. Over hundreds of years, architects have developed and refined different drawing types and techniques that help to communicate these ideas to people. Let’s take a look at some drawings of the Pantheon to see how they communicate.
The drawings in this post come from two different sets. The more yellowish of the two are older drawings from by Antoine Babuty Desgodetz in 1682. The grayscale drawings are the newer set from Francesco Piranesi in the 18th century.
Both of these sets of drawings were done after the construction of the Pantheon, but they are still good for communicating some of what would be necessary to create the building. Even if you have never been to the Pantheon, these drawing sets will provide a feeling of what the building is like.
Plan drawings are the most common architectural drawings. Think of them as a map of the building, as they provide a view of the layout from above. Imagine cutting horizontally through a building at about three feet (or approximately 100cm) above the floor level and drawing everything that was sliced through. In some drawings, the walls are shaded black, while in others they are given a lighter texture. The black portion in drawings is called Poché, and indicates everywhere that a wall or column was cut through for the drawing. Sometimes plan views also include more details than just what is at the 3′ level. They often include floor coverings, furniture, kitchen and restroom fixtures, appliances, or stairs.
Some plan view drawings happen at other levels in a building. In this drawing, there is a plan of the attic space, as well as a reflected ceiling plan, showing the inside surface of the dome.
Here’s another plan that shows the roof, as well as the coffered ceiling. Piranesi’s drawings go beyond the typical role of a plan view of communicating wall thickness, door and window locations, and the partitioning and sizes of a space. His drawings have much more detail in the shading and texturing, and are much more informative about the qualities of the space.
Section drawings involve the same cutting technique as plans, although the cutting plane is vertical instead of horizontal. The point of a section view is to show the heights of each floor, and any complex structures like strange ceilings.
Sections are typically cut at right angles to the axes in a building, and unless their position is obvious, there are often reference lines on plan views to show where the section cuts fall. In the two drawing sets here, those reference lines are absent. The Desgodetz sections are fairly simple, cutting through the center of the dome along the longitudinal and transverse axes, with one section through the portico.
The Piranesi sections are more interesting. The shadows are shown as if the building actually were cut and sunlight was streaming in. This technique helps to communicate the depth of the building much more clearly than the Desgodetz sections.
In addition to the same sections as Desgodetz, Piranesi drew a portico section looking back towards the building, without the wooden roof structure.