Regarding the 180-Degree Turn From a 90-Degree Standard

By Roger K. Lewis
Saturday, April 16, 2005

Judging from contemporary architecture featured in the media, you might think that the 90-degree angle is passé. Among current architectural fads, non-orthogonal design -- shaping architectural mass, space and surface without using right angles -- is increasingly evident.

Architects seem to be designing ever more projects incorporating not only acutely angular geometry, but also complexly curved or faceted walls and roofs.

We see this in many dynamic recent projects: the new, glass-sheathed Seattle Public Library designed by Rem Koolhaas; the starkly symbolic, zig-zagging Jewish Museum in Berlin designed by Daniel Libeskind; any project, built or unbuilt, designed by Zaha Hadid; and, of course, the metal-clad, exploding and colliding forms crafted by Frank Gehry.

Non-orthogonal geometries can be aesthetically and functionally appropriate. But their use in many projects seems arbitrary and capricious. Too frequently, such geometries are little more than willful gestures having little to do with project circumstances or rational construction.

Like many once-original ideas, non-orthogonal design has gone from being special to being trendy.

Strong architectural concepts reflect project conditions as well as the creativity of the designer. But an innovative idea, once executed, can catch the eye of other designers and appeal to them for purely visual reasons. The catchy, aesthetically stimulating idea then begins appearing elsewhere, and before long it has become little more than a faddish, overused motif.

Departing from right angles is not intrinsically wrong. The history of architecture is replete with wonderful compositions based on triangles, hexagons, octagons and irregular polygons, not to mention circles, ellipses, parabolas and other curves.

Use of these geometries is typically motivated by four considerations.

? Structural system stability. Because the triangle is the only inherently stable polygon, architects and engineers have long exploited triangular geometry. Triangles occur primarily in supporting components made by assembling linear elements of wood or steel: walls, vaults and domes.

? Functional plan configuration. Theaters, auditoriums, churches and building lobbies commonly have non-orthogonal geometries to achieve desired acoustical, visual and even psychological properties.

? Site factors. Unconventional architectural geometries are most frequently influenced by site constraints or opportunities -- lot size and configuration, slope, views, vegetation, soils, abutting properties and zoning. I designed a triangular house in Silver Spring derived entirely from the shape of the lot and mandatory setbacks. And the rhombus-shaped plan of a house I designed in Bethesda directly responded to topography and views as well as bad soil conditions on part of the lot.

Site influences on building geometry are especially evident in Washington, where diagonal avenues cutting across the street grid have created hundreds of triangular and trapezoidal lots. The L'Enfant Plan geometry has affected buildings large and small, from the monumental East Building of the National Gallery of Art to the recently built National Association of Realtors headquarters on a sliver of land facing New Jersey Avenue NW.

? Artistic expression. Architects sometimes embrace non-orthogonal geometries for symbolic or purely aesthetic reasons. Circles and arcs of circles permeate and shape almost every space inside the new National Museum of the American Indian, conceived by Canadian architect Douglas Cardinal. Cardinal's curvilinear fixation is both aesthetic and symbolic. He clearly favors circles and curves, believing them to be more representative of forms found in nature, where right angles and perfectly straight lines are rare.

Nevertheless, right angles and straight lines are hardly passé. Indeed, they are pervasive and enduring for compelling reasons.

Most interior spaces work best for most people when walls are perpendicular to floors. Likewise, rooms, corridors, closets and garages are most flexible and efficient when their walls intersect at right angles.

Because of the linear nature of manufacturing -- milling, rolling, extruding -- architectural components are almost always rectilinear or planar. Just look at doors, windows, bricks and lumber. The same holds true for most items placed within buildings: beds, bureaus, desks, tables, chairs, bookshelves, kitchen cabinets and appliances.

At the urban scale, relatively straight streets with parallel curbs surrounding rectangular blocks have proved to be the most widespread and functionally reliable pattern. This pattern embodies 90-degree street intersections, considered by traffic engineers and planners to be the safest. Of course, this pattern also reflects and perpetuates the dominance of rectangular buildings on rectangular lots.

In light of the right angle's understandable "rightness" in so many circumstances, departing from it always should be done thoughtfully and wisely. Instead of simply being whimsical and different, it should be purposeful and, equally important, aesthetically justifiable. Otherwise, today's unconventional geometry can easily become tomorrow's cliché.

Roger K. Lewis is a practicing architect and a professor of architecture at the University of Maryland.

© 2005 The Washington Post Company