Optics of Scale

Height Fright ... Fear of Height in the Suburbs

As Sydney groans at the prospect of increased residential density, the thorny subject of building height inevitably comes to the fore during approval processes. SEPP 65 remains almost silent on the issue of height, leaving a vacuum for inarticulate and emotional debate. Typically, Development Control Plans specify height as absolute dimensions measured in numbers of storeys or RLs not to be exceeded.

These rigid preconceptions can be stifling to proper urban design processes. If quality architecture is to transcend the sometimes blindly numerical local government controls, then some rational tools for understanding height need to be developed. Fortunately, such a tool does exist: “Der Optische-Maassstab”. Its description in this paper might assist architects in taking a lead to elevate the debate.

Scale ... Tuning Height to Place

Any height control, prescribed in the absence of context, is probably meaningless. Height is a linear measurement which, on its own, isn’t very helpful in assessing the desirability of any proposed new building. Height is only part of the story.

It is the context in which the height is perceived that brings relevance to a building’s vertical dimension. By observing a building from various vantage points we are engaged in an evaluation of its scale as well as the scale of the public space that it helps to define. It is the control of scale that is the more important matter than height.

While height is just a vertical dimension, scale, on the other hand, is a branch of human psychology. Height is a fact; scale is a qualitative perception. Scale can be manipulated to create grandiosity or to ameliorate grandiosity. 

Remembering Forgotten Knowledge

In these first few years of the 21st century it is anomalous that Sydney should be wrestling, seemingly for the first time, with an issue that has been refined through previous centuries in Europe; the concept of scale in civic design.

Der Optische ... Maassstab

Over the last few years I have noticed several references in urban design books to Hermann Maertens’ book, Der Optische-Maassstab, (The Optics of Scale) published in 1877 and revised in 1884. These books contained intriguing summaries of theories on the viewing angles through which scale is perceived in public plazas. I attempted to obtain the source text through architectural libraries around the world, but with no luck. Scott Carver’s librarian ultimately traced an original 1884 copy to an antiquarian bookstore in Switzerland, so we bought it.

As far as I can tell there has been little discussion since the 1950s and 60s of Maertens’ theories, and what discussion there has been has concentrated on architects’ responsibilities in matters of good civic manners and picturesque-ness in civic design. These would prove to be matters over which architects had little control or interest as cities headed high-rise.

Of course, in the 1870’s Maertens had only Renaissance precedents to refer to since modernism was yet to occur. Perhaps this is why his principles of the optics of scale have been unfortunately subsumed into aesthetic debates about historical styles and human scale. This is a pity since his observations on optics are principally about the geometry of perception and, as such, stand free of issues of style and humanism. 

Maertens’ Optics of Scale (Der Optische-Maassstab) can be usefully employed today to predict effects of scale, and to enable a shared understanding of scale, during development approval processes. This is true regardless of the style or artistic expression of the architect.

The principles are no more mysterious than the proving of sightlines in a theatre or sporting arena. Just as sightline analysis protects the interests of the observer in every seat in a theatrical arena, so too can the interests of the moving pedestrian be appreciated and protected.

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