Raul Kalvo

This presentation presents digital tools to support observational studies in pedestrian movement and perception in the built environment. Speakers’ bio Raul Kalvo (1983) is an architect and computational designer. Prior of joining Tampere University of Technology as a researcher he founded computational design office Inphysica Technology Ltd and held a researcher position at City Form Lab in Singapore University of Technology and Design (SUTD). His research topics ranged from fabrication methods to urban accessibility models. Raul Kalvo is currently lead developer for “Urban Network Analysis for Rhino” and “Grid Structure Fabrication toolset for Rhino”. Kalvo has been honored by Singapore President Design Award, best paper award at SimAUD and been multiple times nominee for EAIA Annual Prize in exhibition category. He has also worked as an architect for 3+1 Architect and a lecturer at Estonia Academy of Arts. He has lead workshops in numerous firms and institutions, such as RMIT (Me...

Research on urban form and walkability suggests that on average smaller blocks are better for pedestrians. We explore how block sizes, plot dimensions and street widths affect pedestrian accessibility in regular grids. Pedestrian accessibility is captured by the gravity index, which is proportional to the number of neighbouring plots that can be reached within a given walking radius and inversely proportional to the travel costs involved. Pedestrian accessibility is measured for the original town plans of wellknown US and Australian grids and compared with thousands of computer simulated grids, analysing how close the grids come to the theoretical maxima of pedestrian accessibility, given plot sizes and street dimensions. The findings show how dimensions of plot frontages and depths, street widths and block lengths affect pedestrian accessibility in gridiron urban environments. Block lengths have a nonlinear relationship to accessibility and smaller blocks are not necessarily better...

Abstract Big data from smartphone applications are enabling travel behavior studies at an unprecedented scale. In this paper, we examine pedestrian route choice preferences in San Francisco, California using a large, anonymized dataset of walking trajectories collected from an activity-based smartphone application. We study the impact of various street attributes known to affect pedestrian route choice from prior literature. Unlike most studies, where data has been constrained to a particular destination type (e.g. walking to transit stations) or limited in volume, a large number of actual trajectories presented here include a wide diversity of destinations and geographies, allowing us to describing typical pedestrians’ preferences in San Francisco as a whole. Other innovations presented in the paper include using a novel technique for generating alternative paths for route choice estimation and gathering previously hard-to-get route attribute information by computationally processing a large set of Google Street View images. We also demonstrate how the estimated coefficients can be operationalized for policy and planning to describe pedestrian accessibility to BART stations in San Francisco using ‘perceived distance’ as opposed to traversed distance.

We introduce a version of the Huff retail expenditure model, where retail demand depends on households’ access to retail centers. Household-level survey data suggest that total retail visits in a system of retail centers depends on the relative location pattern of stores and customers. This dependence opens up an important question—could overall visits to retail centers be increased with a more efficient spatial configuration of centers in planned new towns? To answer this question, we implement the model as an Urban Network Analysis tool in Rhinoceros 3D, where facility patronage can be analyzed along spatial networks and apply it in the context of the Punggol New Town in Singapore. Using fixed household locations, we first test how estimated store visits are affected by the assumption of whether shoppers come from homes or visit shops en route to local public transit stations. We then explore how adjusting both the locations and sizes of commercial centers can maximize overall vis...

This paper introduces a method for creating double-curved grid structures made out of flat components, where fabrication is limited to only 2-dimensional cutting, making complex architectural structures accessible to a wider audience at a lower cost. The focus of the paper is to identify the limitations and to map the geometric solution-space of the method for real world construction applications. A double-walled nature of the structure enables us to significantly reduce the geometric complexity of the grid structure’s nodes – instead of needing to find a combined geometric intersection for all edges meeting at a node, our solution instead requires determining a pair of adjacent planes at a time, as many times as a node’s degree. But if any of these pairs of planes around a node is torsioned relative to the node’s normal, then collisions might occur between different pairs of planes. This paper discusses the geometric solution-space under which such collisions are avoided, making the structural joints easy to build. As a proof of concept, we demonstrate the use of this method in a design-build pavilion that was realized at the Singapore University of Technology and Design in 2013.

Research on urban form and walkability suggests that on average smaller blocks are better for pedestrians. We explore how block sizes, plot dimensions and street widths affect pedestrian accessibility in regular grids. Pedestrian accessibility is captured by the gravity index, whichis proportional to the number of neighbouring plots thatcan be reachedwithina given walking radius and inversely proportional to the travel costs involved. Pedestrian accessibility is measured for the original town plans of well-known US and Australian grids and compared with thousands of computer simulated grids, analysing how close the grids come to the theoretical maxima of pedestrian accessibility, given plot sizes and street dimensions. The findings show how dimensions of plot frontages and depths, street widths and block lengths affect pedestrian accessibility in gridiron urban environments. Block lengths have a non-linear relationship to accessibility and smaller blocks are not necessarily better for pedestrians. In many cases, larger blocks have greater pedestrian accessibility than smaller blocks, which might explain previous variable findings on the effects of blocks sizes on walkability. Though block lengths in most of the famous grids we investigate come close to achieving maximum possible pedestrian accessibility levels, some of them could provide users with as much as 12 per cent more accessibility if their lengths were optimized for pedestrians. The lengths of the Manhattan and Indianapolis blocks come closest to maximizing pedestrian access, given their original plot and street dimensions. We illustrate a few prototypical block sizes that maximize pedestrian accessibility and may be suitable for pedestrian-friendly subdivisions in contemporary urban planning.

We introduce a method for creating free-form
architectural structures out of 2D domain line networks. The
resulting structure combines principles of thin shell and
single-layer grid structures. The innovation lies in a threedimensional
geometrical arrangement, where all structural
elements can be cut out of flat panels. The advantage of the
proposed method is that structural support systems can be
created for a wide variety of line networks using simple
cutting technology (e.g. saws, laser-cutters, 3-axis CNC
routers), making the construction of geometrically complex
structures accessible to a wider audience at a significantly
lower cost. We illustrate theoretical possibilities of the
approach and demonstrate a full-scale application on a 200
square-meter pavilion built from plywood panels and clad
with sheet-metal tiles at the Singapore University of
Technology and Design. An analogous approach can be
used with a high degree of flexibility to fabricate complex
structures of different shapes and patterns for various
building applications.