|photo from reference 1|
Various models are needed in order to understand the dome and its distortion. The computer reconstruction of Santissima Sindone is based on a side-elevation [reference 1] shown below. From this elevation, one is able to recreate pieces of the interior structure of the dome by using basic geometric shapes. The first basic shape exists at the top of the dome. Since the model is of the interior structure, this shape appears to be the top half of a sphere or a hemispherical dome, not the spire. This hemispherical dome sits on top of a section that in simplified geometric terms is a portion of a cone. Below the cone is a cylinder. The base of the cylinder ends at the clear horizontal lines located at the center of the side-elevation. These lines correspond to the large circle seen in the picture above. The remainder of the elevation no longer comprises the interior of the dome, but the interior of the chapel.
Although these three shapes provided a visual idea of Guarini's dome, two more shapes were used in order to create a more accurate representation. These two shapes lie between the cone and the cylinder. Above the cylinder is a section of the model that contains pentagons on the walls. This section is labeled the trapezoid layer. This is because the circular arches between the pentagons have been simplified by representing the top of the windows as triangles rather than semi-circles. So, the sections of the wall between the windows form trapezoids. Above the trapezoid layer is a cone made up of six rows of semi-circular windows. Based on the measurements taken from this elevation, it is evident that the first five layers lie on a common cone (main cone), while the bottom layer is a slightly different conical section, the base cone.
In this way, one is able to regenerate Guarini's dome. So, the final model
that was created included five basic parts and shapes: a hemispherical
dome, main cone, base cone, trapezoid layer, and cylinder. This forms the
simplified model since it is made up of basic
shapes taken from the side-elevation in reference 1.
|photo from reference 1|
Guarino Guarini used optical illusion in his
creation of the dome at Santissima Sindone. When standing directly
below the dome and looking up, the brain naturally assumes that the
distances between the hexagon layers are equal, while the eye perceives an
illusion that the differences between the layers are decreasing. Guarini
decreased the height between each triangle layer creating the illusion that
the dome recedes farther up into space than it really does. So, to study
this optical illusion, one can arrange the heights between each layer to be
equal to create a model of what the brain thinks it is naturally seeing.
The shape that is produced is a representation of what the dome would have
looked like without the distortion in the height between triangle layers.
|Optical Illusion & Projection in Domes: A Study of Guarino