Explaining optical illusion in classical architecture

Abstract

This report addresses the phenomenon of optical distortion found on architectural elements. It investigates how the distortions occur and how they are corrected. In Part 1, two examples of refinement that correct such errors are explained. Both of them are extracted from classical architecture.(Greek architecture 650-30 B.C.) They are the shaping of columns and the curving of horizontal elements on facade. In Part 2, the report attempts to explain the previously stated phenomenon, using the strategic theories and the structural theories. The result of the investigation shows that a straight column will appear to be thicker towards the top. This distortion comes from the confusion of visual depth. Ancient Greek architects used the method of entasis to shape their column so that they taper in opposite manner to cancel out the thickening effect. Therefore, the result also shows that the base of a triangular top of a facade will appear to sag. This error arises from the incapability of the eye to present a true picture of the scene. Blurring of images and the effect of summation of neural activities on the retina are responsible for such distortion. To correct this, architectural elements that compose the base of the triangular top of the Parthenon's facade are made to perform a slightly convex outline. No contemporary architectural examples that possess similar refinement are identified. Correcting optical distortions is not practised by architects in these days. One possible reason is that people have knowledge of how things are constructed and this overruled the distorted geometries that the eyes present. The other reason is that time and cost constraints do not favour such kind of refinement.