An Introduction to Built Forms
UrbanFootprint built forms depict different building, block and neighborhood configurations and their associated demographic attributes. Represented in UF as bundles of built form and land use characteristics, built form types make up the palette of development options used to create land use scenarios, allowing you to test a wide range of alternative future land use patterns.
Built forms consist of components and types. Components are the parts for making building and block types; they are not used for painting. They can be empirical or prototypical buildings, as well as parks.
Types are split into buildings, blocks, and places, which are designed for painting at different scales, from individual parcels and city blocks, to neighborhoods and districts.
Building and block types are blends of one or more components.
Place types are blends of one or more building and/or block types.
Figure 1. Nested structure of UF built forms
Unlike typical land use designations, built forms bridge the gap between simple land use classifications and physical built form. Land use designations are typically defined first by their major use (e.g. residential) and second by their development intensity (e.g. single-family vs. multifamily). More detail is not necessarily required for zoning. However, detailed assumptions are necessary for robust analysis and they enable UrbanFootprint to be flexible across scales.
The major attributes of built forms are:
- land use designation
- site characteristics (e.g., building and parking footprint, hardscape vs non-hardscape coverage)
- building characteristics (e.g., building area, floor area ratio, number of floors, height)
- parking characteristics
- average residential floor area and dwelling unit counts by type
- average non-residential floor area by sector and subsector
- population, residential and employment densities
Using Built Forms
Built forms serve three main purposes within UrbanFootprint:
- Classifying geographies (parcels, Census Blocks, etc) according to their empirical existing conditions data
- Deploying change via painting scenarios
- Providing the detailed inputs required by UrbanFootprint’s analytical modules
UrbanFootprint inspects existing conditions data, using a density matching algorithm to assign geographies a UF built form type. Unlike painting, this does not modify the underlying data; it splits geographies into logical groupings by either land use designations or intersection density of the street network, then finds the closest match in terms of dwelling unit and employment densities. Aggregate scale geographies (e.g. census blocks) are assigned place types by default, while parcel-scale geographies are assigned building types. For more detail on base canvas translation, see the base canvas creation documentation.
Built forms are also used to deploy change onto the landscape in order to model urban growth or land conservation. In scenario modeling, this is known as painting. Painting wipes away any existing development. In greenfield areas, new development and net growth are therefore the same. In already urbanized areas, painting models complete redevelopment (new development is greater than net growth because some units were demolished and replaced). For example, let’s say a parcel has one existing single-family unit on it, and you paint a four-unit multifamily building on it. New development is four, but net growth is three. Now, let’s say you do the reverse and paint a single-family home where there is currently a four-unit apartment building. New development is one and net growth is negative three. Along with urban types (building, block and place), you can also paint “landscape types”. This would model conservation of land, applying zero dwelling units and/or employees.
Built forms can also be used to refine the existing conditions data, essentially “painting on the base canvas”. The same tool that enables you to model future change to the built environment also empowers you to vet — and where necessary — improve the existing conditions data.
Analysis module inputs. Finally, the detailed attributes of built forms supply the land use and buildings inputs required to model the full range of UF metrics, from building energy and water use to fiscal impacts.
Key Built Form Concepts
The UrbanFootprint built forms system allows you to capture the complexity, range, and nuance of urban form and land use. In order to make built form creation transparent and defensible, UrbanFootprint employs a nested hierarchy comprised of individual components, which are grouped together to form types. Components—which include buildings, parking structures, and parking lots, parks, and other urban elements—are used to construct prototypical or average building types for a project area. In turn, building types—as well as components—are used to construct hypothetical city blocks, known as block types. Finally, to construct districts, known as place types building and/or block types are used.
This clear hierarchical structure helps ensure that types are grounded in real-world, tangible elements. The alternative—directly asserting population and employment densities and built form characteristics instead of combining components—can yield unrealistic types, whose densities do not align predictably or reasonably with development characteristics. The feasibility of types can be difficult to vet, particularly at the block and place type scales. It is particularly difficult to trace the downstream impacts of unrealistic attributes, which often show up in analysis module results.
In short, the detailed inputs for built forms are abstractions of the real world. The built environment is complex and varied—although the built forms setup process is input-intensive, its consistency and grounding in tangible components helps ensure more realistic scenarios and consistent, transparent analytical outcomes.
More information about our Built Forms Manager are coming very soon; If you have any questions feel free to ask via our Chat app or via email!