surrogaattilohkot

Surrogaattilohkot is a term used in Finnish urban planning and architectural modeling to describe surrogate blocks, i.e., simplified representations of real city blocks or land parcels used during early design stages. A surrogaattillohko serves as a placeholder that allows planners to test layouts, scale, and circulation without requiring precise parcel data.

In practice, surrogaattilohkot are typically rectangular prisms or extruded footprints defined by standard dimensions or parameterized rules. They function within 3D models or geographic information systems as stand-ins for actual blocks, and they can be enriched with generic attributes such as land use, expected density, or frontage length to support analytical tasks like traffic simulations, daylight analysis, and pedestrian movement studies. They are designed to be easily replaceable with accurate parcel geometries and building programs as a project progresses.

Benefits of using surrogaattilohkot include faster iteration during early design, clearer communication with stakeholders, and reduced risk when exploring multiple urban-form scenarios. Limitations arise from their abstraction: irregular site shapes, topographic constraints, and micro-scale details are often omitted, which can lead to over- or underestimation of certain performance aspects if relied on too long in the design process.

Historically, the term appears in Finnish planning discourse and software documentation as a practical technique for rapid prototyping of urban forms. It complements other schematic massing methods and traditional placeholder approaches in BIM and GIS workflows. See also massing models, surrogate modeling, and placeholder concepts in urban design.