Infill development has been seen as one of the solutions to urban challenges. However, it changes the dynamics and visual appearance of the neighborhood. As infill development usually requires the acceptance of local stakeholders, their perceptions of the resulting intensified housing have a significant role. In this study, customized visualizations illustrating scenarios of infill development were made from the perspective of individual apartments in neighboring residential building. The usefulness of customized visualizations for local stakeholders was studied in the Tammela test area. A 3D virtual model of the existing environment was created. Models depicting the alternative infill buildings were added to the 3D model, which was used to create customized visualizations. These visualizations were utilized in the interviews of local stakeholders. The findings indicate that the customized visualizations help stakeholders conceptualize the impact, and plan and manage the infill development. Visualizations can also be seen as a tool for a resident-driven approach to intensifying housing.
The intensification of urban areas in its many forms―such as compact city development [
Urban infill projects change both the dynamics and visual appearance of their neighboring area. Local stakeholders’ opinions concerning infill development depend on their perception of how the neighborhood would change. In the relevant literature, not-in-my-backyard (NIMBY) outlooks [
One way to reduce the local stakeholders’ concerns about the infill development is to integrate the stakeholders in the planning process. Von Haaren, Warren-Kretzschmar, Milos, and Werthmann reviewed different design approaches to landscape planning and emphasized the need to include local stakeholders [
Visualizations hold the potential to help conceptualize the effects of infill development for local stakeholders and help engage them in the planning process. A study by Lewis and Sheppard on visualizing the effects of forest management plans for members of indigenous communities in Canada showed that 3D visualizations were considered far more explanatory than traditional presentation media, e.g., maps [
To involve stakeholders, the visualizations should be relevant for them. They should offer the possibility of accurately evaluating and giving feedback on the proposed plan (cf. [
In construction, new building projects are commonly visualized by using virtual 3D models of the planned buildings [
In this study, we create customized visualizations of the infill development project for every individual apartment of a neighboring residential multi-story building by using 3D models of the project and the existing environment. These floor-by-floor visualizations are used together with animations, in indicative interviews of local stakeholders. The aims of this study are to test the feasibility of producing customized visualizations from 3D models, to explore stakeholders’ attitudes and perceptions towards them, and finally, to test the utility of these customized visualizations. The findings of the study contribute to the literature on the tools of resident- driven planning, visualization techniques, and housing intensification possibilities.
Either static or interactive 3D visualizations can be utilized for public consultation in construction projects. Images and plans are considered static visualizations, and applications of virtual environments and gaming technology are considered interactive [
For presenting interactive visualizations, different techniques can be used in addition to regular computer monitors. The scenes can be examined in immersive Cave Automatic Virtual Environments (CAVEs) [
For interactive visualizations, accurate 3D models are required. They can be produced from the existing environment with surveying methodologies. The alternatives are geodetic measurements, photogrammetric techniques, and laser scanning. Modern photogrammetric applications utilize dense image matching algorithms, allowing the automatic creation of 3D point clouds of the scene [
In Finland, apartments are typically owned in the specialized limited company form known as a housing company. The shareholders do not own any real estate units but the shares they own entitle them to possess their apartments. If on freehold, the housing companies are in the key role―deciding on and initiating the infill development on their plots [
A housing company is managed by a board with the assistance of a hired housing manager who acts as the chief executive officer of the company [
For this study, an individual housing company with infill development potential located in Tammela was selected. Currently, one seven-floor residential building with 32 apartments and a low-rise commercial building are situated on the plot. Tammela is a neighborhood with approximately 6500 residents, located in the center of Tampere, the third biggest municipality in Finland. The city has created a strategic vision for the intensification of the relatively loosely built neighborhood and outlined plans for its infill development on a general level. The aim is to build housing for 4000 new residents [
The empirical part of the study consisted of two components: the creation of customized visualizations, and their use in indicative interviews of local stakeholders. The creation of synthetic views from arbitrary viewing perspectives requires a complete 3D model of an area. As there was no suitable 3D model of Tammela available, several data sources were utilized for 3D model generation. To achieve complete 3D models of the buildings, both terrestrial and airborne data were used. Based on the models, customized visualizations depicting two alternative infill development scenarios were created.
The aim of the interviews was to explore local stakeholders’ perceptions of customized visualizations illustrating a small-scale infill development in the proximity of their apartments. It was expected that the findings provide indications of the utility of 3D models as a tool to illustrate different options of infill development for decision makers.
TLS data were collected with a Faro Focus 3D laser scanner (
The National Land Survey of Finland (NLS) provided pre-oriented ALS data (with a point density of 0.5 points per square meter) and orthoimages. In addition, terrestrial photographs were used to texture the model. The ground sample distance of the orthoimages was 0.5 m. Terrestrial images were taken with a Nikon D700 camera and 14 - 24 mm f/2.8 lens. The lens was fixed at 14 mm. The camera was calibrated and lens distortions were removed from images [
The 3D model of the existing area was produced by integrating the TLS and ALS data. The low point density of ALS data prevented the modeling of small details. However, with this data it was feasible to create a digital terrain model and extract coarse outlines of existing buildings. ALS data was classified to ground, building, and vegetation points with the Axelsson method [
It is essential to ensure the common coordinate frame for multi-source data sets [
In order to increase the photorealistic appearance, the final visualizations were produced from textured building models, using Blender software. The textures of roofs were extracted from aerial orthoimages. For the walls, terrestrial images with the size of 1024 × 1024 pixels were applied. Texture images were rectified to the wall planes by projective transformation [
There were also some trees in courtyards. The locations of the trees in the model were extracted from the laser point cloud. Scaled and rotated tree objects were placed in those locations. The tree object used was a typical rendering tree, consisting of 39 triangle faces textured with two texture images (
Specification | Faro focus 3D |
---|---|
Field of view | 360˚ × 305˚ |
Measurement range | 120 m |
Max. speed (points per sec) | 976,000 |
Beam diameter at the exit aperture | 3 mm |
Beam divergence | 0.22 mrad |
Distance measurement accuracy at 25 m | ±2 mm |
Max resolution hor. × ver. | 0.009˚ × 0.009˚ |
Max points 360˚ hor. × ver. | 40,960 × 40,960 |
Laser wavelength | 905 nm |
Laser power | 20 mW |
was used, because the variation of tree species in the test area was limited. In order to reduce the effect of the similar appearance of trees, the tree objects were rotated randomly around the height axis, and scaled according to the sizes of the actual trees.
A 3D model of the infill building was created manually. Laser scanning data and the layout plan of the area were utilized to define the correct location and size of the new building. In order to simulate high and low infill building alternatives, two models with a different number of floors were created. The height of the buildings was defined by calculation, based on a floor height of 2.7 m.
The textures for the models of infill buildings were created by combining a set of images depicting contemporary building facades that were separately photographed. For the two models, different textures were created. The textures were created by forming a mosaic of geometrically corrected images of existing buildings. In
After the 3D models were ready, the customized visualizations were created by rendering the infill development model and the environment model. For each residential floor of the adjacent building, three locations on the floor were used to create visualizations of the infill building. In total, there were 18 camera positions. For each position, three images were rendered, depicting the scene from the window in three scenarios: the current situation, with a new six-story building, and with a new four-story building. In total, 54 images were rendered.
In order to recruit interviewees, invitations to participate in the study were delivered to all apartments. The participants of the study were limited to the shareholders (as decision makers) of the selected housing company, and thus, tenants were excluded. The reason to exclude tenants was based on the fact that Finnish legislation related to housing companies acknowledges only shareholders’ right to participate the decision making concerning the infill development in the area governed by the housing company.
Shareholders were asked to fill in a short questionnaire regarding their views on the potential infill development within their housing company and neighborhood, and their willingness to participate in an interview. Altogether six responses were received, out of which one was willing to fill in the questionnaire but declined the interview. In order to increase the response rate, another recruitment round was performed. However, no additional responses were received.
Four interviews were carried out during fall 2013 and spring 2014 (one of the potential interviewees could not be reached, despite multiple attempts). The interviewees were the chairperson of the housing company’s board, the housing manager (who were both also shareholders), and two regular owner-occupiers. In total, the interviewees constituted over 10% of the shareholders.
As a warm-up for the interview, the interviewees were requested to describe the housing company in which they were living. After that, they were asked if they knew whether the housing company was currently planning an infill development and, if so, what was their opinion on the matter. This part of the interview served as introduction to the topic.
This was followed by the presentation of a layout drawing illustrating the potential infill development for the housing company. The interviewees were asked to describe their perceptions related to the layout drawing and infill development. In the final part of the interview, the customized visualizations and animations were presented
and the participants’ views on those were discussed. This part was intended to reveal the local stakeholders’ perceptions of the customized visualizations. The interviews lasted between 45 - 90 min and were held in the interviewees’ homes or in a nearby lunch restaurant. The interviews were tape-recorded and transcribed. The interviewees received an incentive (a bag of groceries worth approximately 25 euros) for participating the study.
The data analysis followed the logic of Grounded Theory, in which data-driven categories of the studied phenomenon are created [
Based on the 3D model of the existing environment, and the virtual model of the infill development, it was possible to create customized visualizations. The visualizations help comprehension of the influence of infill development from different locations in the adjacent building. With these visualizations, it was possible for individual interviewees to see the effects of the proposed infill development from their own apartment. Some of the apartment specific visualizations are shown in Figures 3-5. The rendered images were printed in A3 size, and arranged in a folder to help locate the correct images for the interviews. In addition, fly-through and street- level animations were created. The videos were also rendered with three setups, showing the current state, with a new six-story building, and with a new four-story building (
The interviews indicate that customized visualizations can help stakeholders conceptualize, plan, and manage an infill development at the early phase of a project. Based on the analysis of the interviews, three main categories were developed to illustrate how the stakeholders perceived the customized visualizations and animations. The first category relates to the planning of the infill development, the second to the perceived impact of the infill development, and the third to the management of the infill development project.
For the stakeholders, the customized visualizations and animations provided the possibility to contemplate the visual design of the new building and its location on the plot. Prior to seeing the customized visualizations, most of the interviewees were worried that the size of the plot was too small for a new building, even when the suggested infill development was to demolish an existing low-rise building and replace it with an apartment house. Seeing the models strengthened their worries of the cramped plot. Some interviewees started to envision a better location for the new building.
“Yes. Oh my! The house [the infill building] is beautiful. It looks like a piece of candy. I have nothing against it but I criticize our house and our small plot. And I can’t help it. And there is the taller [building] then. Oh dear!” (Resident 1)
“It is a terrible chunk to [come] here. It is a terrible chunk. As these buildings are so close to each other here. They are completely side by side.” (The chairperson)
“... but it is in the wrong place. If it would be even ten meters this way, there would be some kind of breathing hole. I mean between this [apartment] house and the other one [the infill building]”. (Resident 1)
After seeing the customized visualizations, some of the interviewees were able to more thoroughly discuss the use of the plot. They mentioned road lines, emergency routes, the routes for collecting the rubbish, and the significance of the trees. For the stakeholders, the customized visualizations provided a chance to better conceptualize the planning of the infill development.
For the interviewees, the customized visualizations assisted in conceptualizing the impact of the infill development on their surroundings. Firstly, the interviewees understood the mass of the new building better after studying the visualizations. This was particularly clear when the interviewees saw the new building from the perspective of their own apartment windows or balcony. This was found out by comparing the perceived effects of the infill development on different floors. Overall, the six-floor building caused more suspicion than the four-floor building. This was due to the mass of the building and the loss of views and/or the living convenience.
Interviewer: “Is there a difference between four and six floors?”
Interviewee: “Well, yes a little. The yard is even more like some canyon [with the six-story building]” (Resident 2)
...
“…there are walls around [unfinished thoughts]. Sure, there are [walls] here as well, but here you have more air space than there [compares the four- and six-story buildings]. It is completely blocked. It does not look very good.” (Resident 2)
...
Interviewee (The chairperson commenting on the proposed six-floor apartment.): “Even worse.”
Interviewer: “What makes it even worse?”
Interviewee: “It blocks our yard. ... Although we are in the middle of the city, you cannot take away the living convenience of people.”
...
Two of the interviewees said that they would not have needed the customized visualizations to comprehend the negative impact of the tall infill building. Nevertheless, the visualizations seemed to enhance their negative views on the infill development and its impact.
Secondly, some of the interviewees were able to better comprehend the unequal position of the residents living in the different parts of the existing apartment building in regard to the infill building. The interviewees were able to browse through folder of customized visualizations from every floor of their building. They were concerned about the residents in the lowest floors and those of one end of the existing building, as the new building would block their views the most.
“... it is quite blocked then. Most of all for them; for those who are living there.” (Resident 2, referring to the people living at the opposite end of the existing apartment house, where the view was more blocked)
Thirdly, with the customized visualizations, the interviewees were able to recognize the streets and buildings of the neighborhood. This was particularly clear when compared to the illustrations of the infill development they had seen earlier in the newspapers or at the infill development briefing held by the city. All the interviewees were very critical of the infill development illustrations they had seen earlier.
“It is very clear here. I recognize very clearly what is proposed through all these pictures. I don’t have to ask ‘What on earth is that?’ and ‘Where is that street?’ ... I saw it very clearly and recognized all the buildings in the neighborhood. This is a thousand times better than the white shoe boxes...” (Resident 1, comparing the visualizations to the illustrations presented at the city briefing)
Fourthly, the loss of trees, green areas and urban fauna due to the infill development caused concern to one interviewee after seeing the 3D models.
The possibility of an infill development had been discussed earlier in a general assembly of the housing company, and the management had met the representatives of the city and developers. However, no plans for the infill development existed, and the stance of the general assembly towards the infill development on the plot of the housing company was critical. The housing manager considered the customized visualizations essential for planning the infill development. The visualizations would enable both the residents and the management to conceptualize the infill development, assist planning, and make the entire infill development process easier. The housing manager emphasized that tools like customized visualizations had been missing completely from the infill development discussions. The visualizations would be useful in his job. Also, the chairperson saw the customized visualizations as useful tools, especially for residents with no expertise in construction.
“Yes. And this corner―a sizeable building [to be put] there and height; that kind of thing will bring that space. ... And when we get this garage as a storage space and more [storage space will] come here. The garage of the new building would come to this entity and the drive-in here. [With this kind of plan] It will be approved [by residents]. The city has only presented raunchy illustrations in the newspaper.” (The housing manager brainstorms using the 3D models)
“If we would use this, it would be the lower option [four-story building]. But we need this kind of tool. ... Showing how it looks like. And in the same way, if there was not this kind of long mass on the front―so it comes here, to the corner, rises up like this [explains by using the visualizations]. A person can see it will be like this, and this manner of representation is more illustrative.” (The housing manager)
“It makes it easier to conceptualize―this type of working takes the process ahead.” (The housing manager)
According to the housing manager, the use of customized visualizations in the early phase of planning the infill development could bring more control to the residents of housing companies and adds to the possibilities of resident-driven planning. This was considered particularly important in relation to the city-led general level planning for the infill development in Tammela. Both the housing manager and the chairperson were critical of the infill development push made by the city, although they understood the city’s need for housing intensification.
“Infrastructure costs are of course probably the most crucial issue dictating why this needs to be intensified. And that is why the city has made these original plans. They [city representatives] say that if they hadn’t made any of these illustrations―the issue wouldn’t proceed anywhere. But, on the contrary, they [referring to the city’s infill development illustrations and plans] caused the opposition: ‘No such colossus here!’” (The chairperson)
Additionally, many issues mentioned under previous categories would provide valuable input to the management of the infill development process. For example, the decrease of the living convenience and the unequal position of the residents living in the different parts of the apartment house building would have to be considered.
The first aim of the study was to test the feasibility of producing customized visualization of infill development for the local stakeholders. The final customized visualizations illustrate two alternative infill development buildings from different locations in the adjacent building. As the described visualization method relies on 3D models as the source material for producing the visualizations, the tasks and costs of utilizing the method can be divided into costs of modeling and costs of visualization. Both 3D models depicting the proposed infill buildings and their surroundings have to be available before the visualizations can be made. In the presented case, a measuring campaign was required to produce the model of the urban environment. The visualizations were made from a 3D model based on combining ALS and TLS data.
As a terrestrial laser scanner was used in measuring, the cost of the measuring device has to be also taken into account. A one-day measuring campaign was required for acquiring the data, after which several working days were required for modeling. The process of modeling from TLS data has been reported to be very time taking by other authors as well [
After the 3D model of the environment was available, models depicting the infill development scenarios were made. Each scenario of infill development requires separate design model, which leads to manual work. Usually, 3D design models are rendered as 2D illustrations for easy distribution and visualization. For both of these steps a large amount of tools are available, both commercial (e.g. [
In the future, we can assume that the development of measuring technologies continues, making the measuring instruments more efficient and affordable. For larger areas mobile mapping systems would be the most efficient method for collecting detailed 3D data [
When compared with the model presented in [
In addition to the rendered images and animations used in this study, there are alternative methods of visualizing digital 3D models. Game engines can be utilized to produce multimodal simulations, such as that presented by Manyoky et al. [
The second aim of the study was to explore the stakeholders’ attitudes and perceptions towards these customized visualizations by indicative interviews. With the visualizations, stakeholders (here, owner-occupiers and the management of a housing company) were able to see how the small-scale infill development would change the surroundings of their apartments.
Considering the NIMBY attitudes and resistance towards infill development, residents may hold strong senses on the way of living in their neighborhood, and see the infill development as chaotic and conflicting [
Residents often place distrust in the stakeholders planning different developments (e.g. [
Finally, our aim was to assess the utility of customized visualizations in infill development projects. The visualizations offered a possibility to study the visual impact of the infill building from three different positions on each floor of the adjacent building. When assessing the views from apartments, residents of different floors were found to be in unequal positions. For example, the new four-story building barely reached the horizon when seen from the top floor of the adjacent building but completely obscured the view of the people living on the first residential floor. For their apartments, such a project would have had a huge impact, as the interviewees noted. This needs to be taken into account when considering the rights of individual owners and the distribution of the benefits and disadvantages of an infill development.
In addition, the customized visualizations helped the stakeholders to give preconditions for the infill development project, such as the disposition and the number of floors of the infill building and the use of the plot. Customized visualizations can be shown and discussed in joint meetings and could successfully be a part of a participatory decision-making processes. They possess great communication potential by visualizing different scenarios [
Detailed visualizations reduce the possibility of misunderstanding and ease the orientation of a viewer [
The management of the infill development project in the housing company benefits from the customized visualizations. Visualizations provide a new tool to help understand and give input to the infill development on the plot of the housing company. The use of customized visualizations could enable resident-driven infill development as opposed to the traditional, top-down planning (see, [
In the future we can expect that improving virtual models enable a more efficient production of visualizations, game engine mediated, interactive visualizations [
In this study, customized visualizations of two different infill development scenarios were made, showing the new buildings from each floor of a neighboring residential multi-story building. The visualizations were made using 3D models of the new buildings and the existing environment. These floor-by-floor visualizations were used together with animations in indicative interviews of local stakeholders. The interviewees were owner- occupiers, a housing manager and a chairperson of a housing company’s board.
The findings indicate that the customized visualizations work as an instrument helping the stakeholders conceptualize the impact of infill development. They can also be used to plan and manage an infill development at an early phase of the project. Additionally, they can be seen as a tool for a more resident-driven approach to intensifying housing (when compared to the traditional, top-down planning) due to their communication, planning, and participatory potential.
In the Tammela area and many other older neighborhoods in Finland, housing companies are the main landowners. Thus, they are the main stakeholders in initiating infill developments and have a key role in decision making. For them, infill development is a viable way to finance major repairs to buildings. Tools, like customized visualizations, will most likely be welcomed by the housing companies considering or planning an infill development. Qualitative research with more interviews would enable a deeper understanding of this topic.
Currently, the technology and know-how required for measuring and modeling the existing environment increases the costs of producing the visualizations presented. As the technology is developed further, these costs can be expected to reduce. If high quality city models continue to emerge, it is even possible that the measuring and modeling work becomes mostly unnecessary for producing the presented visualizations. As producing simple 3D models of planned buildings, and using them for visualization is already quite common, we can assume that with the availability of city models the presented use of visualizations could become more of a standard practice in infill development in the future.
Possible topics of further research include the development of customized visualizations into a scenario-based tool for participatory planning, offering more alternatives for stakeholders to discuss. In addition, the use of customized visualizations in an ongoing infill development project would enable the use of detailed models in the decision making of construction projects.
The ALS data was obtained from the open data service of the NLS. This research project was supported by the Academy of Finland, the Centre of Excellence in Laser Scanning Research (CoE-LaSR) (272195), Research on Resident-Driven Infill Development Possibilities―Case Study in Urban Areas in Finland (REPSU) (255390), The Finnish Funding Agency for Innovation, “A healthy building”―project (40250/14) and the Aalto Energy Efficiency Research Programme (Light Energy―Efficient and Safe Traffic Environments project), the EUE project (2141226), and the Aalto University doctoral program.