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11.1. Local Symmetry

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(Weitergeleitet von Local Symmetry)

This pattern begins a section on broader geometric properties that are included in many other patterns at many scales. We can see these geometric patterns in Biophilic Urbanism, in Place Network, in Courtyard Building, and in many other parts of the city.


11 1 01 Local Symmetry.jpg


Problem-statement: Environmental structures without a legible symmetry are chaotic and ugly. But environmental structures with relentless symmetry at all scales can become lifeless and oppressive.


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Discussion: Symmetry is in many ways the most important property in cities, and in living structures too. There are many kinds of symmetries — bilateral (like our two hands), radial (like the irises of our eyes), and so on. There are also many compound symmetries, like our eyes (each of which is radial while both are bilateral).


But breaks in symmetry are also very important, as we are learning from many fields today, notably physics. A relentless form of symmetry — one that does not break when adaptive conditions require it — is oppressive, and usually indicates a faulty process of generation. (Including a designer who has become megalomaniacal with their design, as can be seen in, say, the vast, overly-symmetrical palaces of some despots.)


A more benign form of symmetry can be seen occurring spontaneously in many places — exquisitely symmetrical at local and human scales, but interrupted at larger scales, especially when topography or other conditions prompt an adaptive shift. This “symmetry-breaking” is actually a key generator of a more complex form of order.¹


Three important points are worth explaining. First, symmetries that contribute to perceiving “life” in the environment exist mostly on the smaller and intermediate scales. In the best-loved examples, there are thousands, if not millions, of cooperating smaller-scale symmetries. They all cooperate to generate coherence instead of randomness. The opposite case — where there is an overall symmetry on the largest scale, but no further small-scale symmetries — is perceived as oppressive.


Second, we instinctively compute the coherence and intensity of multiple symmetries in our field of view, and apparently “feed visually” on high degrees of organized complexity. Yet multiple symmetries on façades and perceivable structures have priority over symmetries of the building’s plan. While those are also important, we may not be able to grasp the ground symmetries in a complex building. We normally cannot see the plan when we use the building at ground level.


Third, monotonous repetition abuses the symmetry idea to generate a hostile environment. The human mind cannot identify meaningful information presented in, say, endlessly repeating blocks or windows, and tires itself in trying to grasp a non-existent complexity. This is why groupings and variations are necessary to break a monotonous symmetry, and why they arose as an essential part of traditional design solutions (see Small Groups Of Elements.)


Nature never shows monotonous repetition. Whenever a design repeats in nature, it adapts to local conditions so that it is never exactly the same. Monotonous repetition thus signals that adaptation has been neglected.


11 1 02 Local Symmetry.jpg
There is a very high degree of symmetry in the Alhambra in Spain, seen above and in the image at the start of this pattern. It includes bilateral, radial and other forms. However, this symmetry exists only at smaller “local” scales. At larger scales the symmetry often breaks, as can be seen in the asymmetrical upper building in this image.


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Therefore:

Use symmetry to create beauty at local and human scales, but use it sparingly at larger scales. Break the symmetry as needed to respond to changes in terrain or other environmental conditions. Do not use symmetry slavishly, but as an asset to be applied within a looser, more complex geometric system.


11 1 03 Local Symmetry.jpg


Use local symmetry to create Construction Ornament and Human-Scale Detail.




¹ The property of local symmetry is discussed at length in Book One (and elsewhere) in Alexander, C. (2003). The Nature of Order: The Art of Building and the Nature of the Universe. Berkeley: Center for Environmental Structure.



SECTION I:

PATTERNS OF SCALE


1. REGIONAL PATTERNS

Define the large-scale spatial organization…

1.1. POLYCENTRIC REGION

1.2. BLUE-GREEN NETWORK

1.3. MOBILITY CORRIDOR

1.4. 400M THROUGH STREET NETWORK

2. URBAN PATTERNS

Establish essential urban characteristics…

2.1. WALKABLE MULTI-MOBILITY

2.2. LEVEL CITY

2.3. PUBLIC SPACE SYSTEM

2.4. BIOPHILIC URBANISM

3. STREET PATTERNS

Identify and allocate street types…

3.1.URBAN GREENWAY

3.2. MULTI-WAY BOULEVARD

3.3. AVENUE

3.4. SHARED SPACE LANE

4. NEIGHBORHOOD PATTERNS

Define neighborhood-scale elements…

4.1. STREET AS CENTER

4.2. PEDESTRIAN SANCTUARY

4.3. NEIGHBORHOOD SQUARE

4.4. NEIGHBORHOOD PARK

5. SPECIAL USE PATTERNS

Integrate unique urban elements with care…

5.1. SCHOOL CAMPUS

5.2. MARKET CENTER

5.3. INDUSTRIAL AREA

5.4. HOSPITAL

6. PUBLIC SPACE PATTERNS

Establish the character of the crucial public realm…

6.1. PLACE NETWORK

6.2. WALKABLE STREETSCAPE

6.3. MOVABLE SEATING

6.4. CAPILLARY PATHWAY

7. BLOCK AND PLOT PATTERNS

Lay out the detailed structure of property lines…

7.1. SMALL BLOCKS

7.2. PERIMETER BLOCK

7.3. SMALL PLOTS

7.4. MID-BLOCK ALLEY

8. STREETSCAPE PATTERNS

Configure the street as a welcoming place…

8.1. STREET AS ROOM

8.2. TERMINATED VISTA

8.3. STREET TREES

8.4. STREET FURNISHINGS

9. BUILDING PATTERNS

Lay out appropriate urban buildings…

9.1. PERIMETER BUILDING

9.2. ARCADE BUILDING

9.3. COURTYARD BUILDING

9.4. ROW BUILDING

10. BUILDING EDGE PATTERNS

Create interior and exterior connectivity…

10.1. INDOOR-OUTDOOR AMBIGUITY

10.2. CIRCULATION NETWORK

10.3. LAYERED ZONES

10.4. PASSAGEWAY VIEW



SECTION II:

PATTERNS OF MULTIPLE SCALE


11. GEOMETRIC PATTERNS

Build in coherent geometries at all scales…

11.1. LOCAL SYMMETRY

11.2. SMALL GROUPS OF ELEMENTS

11.3. FRACTAL PATTERN

11.4. FRAMING

12. AFFORDANCE PATTERNS

Build in user capacity to shape the environment…

12.1. HANDLES

12.2. CO-PRODUCTION

12.3. FRIENDLY SURFACES

12.4. MALLEABILITY

13. RETROFIT PATTERNS

Revitalize and improve existing urban assets …

13.1. SLUM UPGRADE

13.2. SPRAWL RETROFIT

13.3. URBAN REGENERATION

13.4. URBAN CONSOLIDATION

14. INFORMAL GROWTH PATTERNS

Accommodate “bottom-up” urban growth…

14.1. LAND TENURE

14.2. UTILITIES FIRST

14.3. DATA WITH THE PEOPLE

14.4. INCREMENTAL SELF-BUILD

15. CONSTRUCTION PATTERNS

Use the building process to enrich the result…

15.1. DESIGN-BUILD ADAPTATION

15.2. HUMAN-SCALE DETAIL

15.3. CONSTRUCTION ORNAMENT

15.4. COMPLEX MATERIALS



SECTION III:

PATTERNS OF PROCESS


16. IMPLEMENTATION TOOL PATTERNS

Use tools to achieve successful results…

16.1. FORM-BASED CODE

16.2. ENTITLEMENT STREAMLINING

16.3. NEIGHBORHOOD PLANNING CENTER

16.4. COMMUNITY MOCKUP

17. PROJECT ECONOMICS PATTERNS

Create flows of money that support urban quality…

17.1. TAX-INCREMENT FINANCING

17.2. LAND VALUE CAPTURE

17.3. EXTERNALITY VALUATION

17.4. ECONOMIES OF PLACE AND DIFFERENTIATION

18. PLACE GOVERNANCE PATTERNS

Processes for making and managing places…

18.1. SUBSIDIARITY

18.2. POLYCENTRIC GOVERNANCE

18.3. PUBLIC-PRIVATE PLACE MANAGEMENT

18.4. INFORMAL STEWARDSHIP

19. AFFORDABILITY PATTERNS

Build in affordability for all incomes…

19.1. INTEGRATED AFFORDABILITY

19.2. COMMUNITY LAND TRUST

19.3. MULTI-FAMILY INFILL

19.4. SPECULATION TAX

20. NEW TECHNOLOGY PATTERNS

Integrate new systems without damaging old ones…

20.1. SMART AV SYSTEM

20.2. RESPONSIVE TRANSPORTATION NETWORK COMPANY

20.3. AUGMENTED REALITY DESIGN

20.4. CITIZEN DATA