Urban/image: Conceptualizing Amsterdam as urban environment in virtual renderings

Abstract

This article proposes that virtual renderings of speculative architectural projects provide a crucial entry point into the reimagination of sustainable urban life through the production of nature(s) within the city. Drawing on case studies of ‘sustainable’ building projects in and around Amsterdam, The Netherlands, I aim to trace the entanglement of virtual and real environments in imagining green futures. With the concept of the ‘render ghost’, James Bridle situates the people inhabiting virtual renderings ‘in the liminal space between the present and the future, the real and the virtual, the physical and the digital’ (2013). Similarly, the imaginations of nature within virtual renderings of sustainable buildings are situated at a point of in-between, a constant state of becoming. More than just visualizing their respective architectural design, the virtual renderings visualize these designs in a specific space, a specific environment – and how that environment could and would change through the spatial presence of these buildings. What makes these immaterial elements – ranging from computer-generated images to virtual renderings and augmented reality applications – particularly productive as research objects is the subjective nature of the atmosphere created in and through them, an atmospheric imagination of sustainable futures embedded in what Degen et al. call a ‘field of negotiation, tension and ambivalence’ (2017). Atmospheric in their imagination of urban environments, contingent in their temporality between the past, the present and the future, and ambiguous in their spatial grounding in simultaneously specific and generic surroundings, virtual renderings arguably allow for an engagement with the possibilities of alternative urban futures.

Introduction

‘Not just more green, but more importantly better green’: This rather abstract formulation is at the core of the Comprehensive Vision Amsterdam 2050: A Humane Metropolis, the municipal publication outlining the urban planning approach for the upcoming decades. Beyond questions of exaggeration, the role of nature in urban environments is becoming an increasingly pressing issue, entangled with discussions of liveable and sustainable cities at a critical moment of environmental crisis. In recent years, municipalities in European cities, like Amsterdam, have emphasized their commitment to creating neighborhoods centered around sustainability and sustainable living. Crucially, these urban futures are not just envisioned but also visualized, made material, in and across a variety of media. More green, more sustainable, more livable: This is the image and atmosphere of Amsterdam constructed, rendered and repeated in and through mediations of contemporary architecture – especially for designs in their initial funding and development phase. Between visual references to rural pasts and urban futures, these architectural mediations appear to be haunted by the repetition and recycling of imaginations of nature as suspended between spatial and temporal realities. This article proposes that virtual renderings of speculative architectural projects provide a crucial entry point into the reimagination of sustainable urban life through the production of nature(s) within the city. This imaginative potential becomes even more pronounced with the broad variety of digital technologies – both software and hardware – allowing for a photorealistic, multiperspective rendering of urban environments. ‘Modeling practices that make use of digital tools have become ubiquitous in building design and construction’ (Ammon, 2017: 177), writes Sabine Ammon in her discussion of architecture after the digital turn. This article understands virtual renderings as a crucial step in the increasingly cross-mediated practice of architectural writing – architecture as writing – to highlight the processual logic of sustainable design. The increasing reliance on virtual renderings – both visual and audiovisual – in architecture also expands beyond questions of practicality and convenience. As Degen et al. (2017) discuss in their overview of the changing tools architects draw on to imagine and produce future cities, the increasing use of digital visualization technologies plays a crucial role in creating ‘a more ambiguous, “atmospheric” and contingent idea of place’ (p. 21). How technology mediates, produces and enacts our understanding of the environment becomes palpable in the unfolding of architectural writing through and across different media – from digitally rendered buildings and their surroundings to the imagined human and nonhuman bodies moving through these imagined spaces.

In the context of this article, virtual renderings are understood as an important part of this process – in turn encompassing different mediated forms, ‘be they pictures, sketches, renderings, maps, plans, or photographs; be they analog or digital, planar or three-dimensional, ephemeral, realistic, or imaginary’ (Ammon, 2017: v). Partly augmenting, partly replacing traditional architectural scale models, virtual renderings – particularly of architectural projects in their development phase – go beyond (photo)accurate representation. More than just visualizing their respective architectural design, the virtual renderings visualize these designs in a specific space, a specific environment – and how that environment could and would change through the spatial presence of these buildings. The imaginations of nature within virtual renderings of sustainable buildings are situated at a point of in-between, a constant state of becoming. With the concept of the ‘render ghost’, James Bridle (2013) similarly situates the people inhabiting virtual renderings ‘in the liminal space between the present and the future, the real and the virtual, the physical and the digital’. Drawing a connection between the (human) render ghosts and the (natural) environments points to the complex embedding of architecture in environments and environments in architecture. This has to do with the place of virtual renderings in the design process as well: arguably even more so than sketches and models, computer-assisted design (CAD) situates architecture digitally in an environment that is both drawing on and expanding existing urban realities. Rather than just focusing on the building itself, this article defines sustainable architectural projects as increasingly mediated – extending not just into physical spheres but quite crucially also into virtual and digital spheres. Focusing on the production of nature(s) in this mediation allows for an exploration of how the relationship between virtual and physical environments is negotiated – and complicated – in virtual renderings.

Drawing on case studies of two ‘sustainable’ building projects in and around Amsterdam, The Netherlands, I aim to trace the entanglement of virtual and real environments in imagining green futures. As one of the centers for environmentally conscious architecture, focused on but not limited to living with rising sea levels and other consequences of climate change, The Netherlands function as a productive setting to explore the construction and presentation of sustainable architecture – particularly with an international appeal both in terms of potential partners and residents as well as the seeming ‘transferability’ of the design. The two examples discussed here – The Urban Tree Village and ReGen Villages – are not just connected by their national location in The Netherlands (and reference to provinciality rather than urbanity) but also their speculative character. The Urban Tree Village, designed by Amsterdam-based architectural firm Space&Matter and run by a team around project founder Naleye Sultan Buddista, is a concept for a community-centered highrise in Amsterdam bringing together individual apartments and shared facilities across four building blocks, while ReGen Villages, a company started at Stanford University and run by serial entrepreneur James Ehrlich, is an international development plan expanding the vision of integrated living to a whole neighborhood (visualized as a self-sustaining village). At the point of writing, neither project has a definite building site, and neither project has moved beyond the initial design – and funding – phase. This is precisely what makes the virtual renderings of these two yet-to-be-realized projects such productive examples: tracing the production of nature(s) in virtual renderings of these two lighthouse projects highlights both the speculative nature and potential of architectural writing to image urban futures sustainable and sustainably. To do so, this article explores the threefold understanding of place as atmospheric, contingent and ambiguous (as suggested by Degen et al., 2017) through the urban environments produced for ReGen Villages and The Urban Tree Village. The first section discusses virtual renderings as operative images simultaneously visualizing architectural design for expert audiences and imbuing this design with meaning for larger publics. Understanding virtual renderings as ‘active images’ highlights how the visualization of environments in and through them contributes to nature imaginations. The second section proposes that the virtuality of this visualization blends different temporalities in the rendering of urban environments. Particularly for yet-to-be-realized projects such as those discussed here, virtual renderings function as a connection between the solutions of a green(er) past and the promise of a sustainable urban future. How architectural writing imagines, plans and realizes the transformation of urban spaces becomes even more complex when explored through a spatial lens as well. The third section argues that virtual renderings simultaneously position architectural projects in specific and generic environments. This ambiguity implies sustainable architecture as a generic model that can be applied flexibly and independent of specific urban circumstances. Atmospheric in their imagination of urban environments, contingent in their temporality between the past, the present and the future, and ambiguous in their spatial grounding in simultaneously specific and generic surroundings, virtual renderings arguably allow for an engagement with the possibilities of alternative urban futures.

Virtual/real: renderings as operative images

On the use of visualization in architecture, Belén Maiztegui (2020) writes that ‘all of these tools serve as a way of bringing an idea to life’. In doing so, architectural renderings move beyond their function as instructional for the construction process: while – historically and technically – based on technical drawings, they are nonetheless fundamentally different. More than translating the requirements of material steps or even visualizing green(er) neighborhoods, the virtual renderings discussed here are arguably actively producing nature in and through their mediated forms. If ‘we perceive the exterior world through the lenses provided, both literally and on a more symbolic level, by the technological culture that surrounds us’ (Picon, 2004: 115), the ways in which architectural writing provides us with images of sustainable urban futures becomes particularly interesting. As a lens in itself entangled with technological considerations, an analysis of virtual renderings highlights another perspective of the architectural site beyond construction sites – and digital media as a site of architectural writing. Exploring virtual renderings through the lens of operativity follows an interest in the ‘many ways images become active in architecture’ (Ammon, 2017: v), while at the same time understanding architectural media as both operative and performative – not necessarily always simultaneously, but in the larger process of architectural writing. Offering the visual experience of a full ‘environment’, I argue that virtual renderings contribute to the imagination and production of nature at the intersection between virtual and real spaces.

Following Bruno Latour – and the fundamentals of actor-network theory – Reinhold Martin (2017) suggests that architectural drawings ‘gather materials, documents, readers, and writers around themselves, in an ensemble of activities’ (p. 3). Notably, these other materials and documents are also other media forms – which then in turn draw together other media. This emphasis on cross-mediality suggests architectural writing as a process that constantly and actively does something. Understanding virtual renderings, done with and through computer technology, as operative images points to their ‘active doing’ (Hoel, 2018: 11). Importantly, this connects the same image to different audiences in a multitude of meaning-making processes. In their introduction to ‘The Active Image’, Sabine Ammon and Remei Capdevila-Werning (2017) write that ‘images serve as means of representing, as tools for thinking and reasoning, as ways of imagining the inexistent, and as means of communicating and conveying information, but they may also perform functions and have an agency of their own’ (p. v). In their conceptualization, the term ‘active image’ aims to capture both the operative function of architectural media – in conveying measurements, for instance – as well as their performative function – in conjuring ideas of urban futures as in the context discussed here. If it is ‘through an atmosphere that a represented object will be apprehended and will take on a certain meaning’ (Anderson, 2009: 77), highlighting the presence and feel of nature(s) in virtual renderings points to the atmospheric qualities drawn on in the process of architectural writing.

Playing with but not fully following the conventions of technical drawings, the operationalization of the publicly available drawings of The Urban Tree Village ¹ tower becomes more complex. As schematic representations adhering to conventions of size and scale (of different floors, for instance), technical drawings are meant to translate design into a logical set of instructions. As such, they become operational for the building process, and the specialists involved in the building process – from urban planning authorities to the plumbing company tasked with setting up the pipes within the building. The lateral cuts of The Urban Tree Village, publicly available via the project’s website, highlight the different apartment types and shared spaces, the staircases and connections between them as well as the circular design of the building as a whole. The size and perspective of these drawings is similar, but not identical – some featuring the building’s shadow, some featuring interior walls, some even featuring furniture and inhabitants. Placed next to each other, the efficiency of these vertical cuts as operative images in this context is debatable. Still, these images certainly do something – but something that is beyond the technical and objective communication of spatial details. The virtually added details and the similar yet different repetition of the building’s structure separate these lateral cuts from both architectural scale models and architectural plans, moving them closer to virtual renderings with a first implication of the ‘full’ environments created in and through them. Raising the question of what these images are actually meant to communicate points to the complex ways virtual renderings are imbued with meaning. If the affectivity of atmospheres is ambiguous to begin with, as Ben Anderson (2009) suggests, the layering of different meanings and audiences underlines this ambiguity even more. As operational images, virtual renderings of sustainable architecture are charged with creating a ‘sense’ of place that is entangled with the ‘feel’ of nature.

This is, of course, not to say that renderings cannot provide realistic and accurate visualization of proposed projects, ² but rather that this additional effort is rarely undertaken. ‘Design images’, Sabine Ammon (2017) asserts, ‘are characterized by the fact that they do not refer to an actual object in the course of their main use during the design process’ (p. 181). In most cases, architectural renderings are created and importantly also communicated before the actual construction of the building. Not only is the future of physical spaces thereby deferred to virtual spaces, but also further entangled with implicit ideas of (digital) technology – particularly as it comes to sustainability. Both The Urban Tree Village and ReGen Villages are inherently technological projects. As ‘the feel, the atmosphere, the sensoriality, of cities is being created and shared using digital devices’ (Degen and Rose, 2022: 4), it becomes even more obvious that these digitally mediated atmospheres are decidedly ‘natural’ in the virtual renderings discussed here. At the heart of the strategy adopted by ReGen Villages to foster ‘resilience’ in a changing environment lies a specifically developed software system ‘using artificial intelligence and machine learning algorithms to enable thriving and flourishing communities with surplus energy, clean water, high-yield organic food that support urgently needed neighborhood regenerative resiliency’ (ReGen Villages, 2022). However, the circular approach to the production and consumption of resources within the community – based on an interconnected flow of energy, food, waste and water – remains invisible in the virtual renderings. Similarly, the complex and interwoven processes that are highlighted in the lateral cuts of The Urban Tree Village disappear in other visualizations. Instead, the technological and digital processes are visualized in and through their consequences for the environment, their emphasis on turning both of these architectural sites into living and lived in spaces for both human and nonhuman inhabitants. For instance, the virtual renderings for ReGen Villages ³ prominently feature greenhouses that at the same time function as extensions of the living space and sites of vertical farming. As ‘agrihoods’ integrating agriculture into the neighborhood, the virtual renderings emphasize the harmony between the ‘natural’, the ‘farmed’ and the ‘inhabited’ lands without much attention to the potential contradictions between them. The swarms of birds soaring through the sky of almost all virtual renderings might be attracted by the reclaimed land, but in turn would also threaten the careful rows of fields and fruit trees featured in the virtual renderings. Yet, for the affective atmosphere of these technologically informed and produced images, the references to nature and the natural are crucial.

Here, the render ghosts discussed by James Bridle and the cinematic phantoms discussed by Harun Farocki come together: ‘The phantom perspective relates, in other words, to the capacity of machine-made images to leap beyond the human scale, reporting on events outside the scope of human sensibility’ (Hoel, 2018: 13). As operative images, virtual renderings are tasked with the imagination of urban futures and their potential atmospheres that cannot yet be ‘felt’ without technological mediation. In their framing, constructing and projecting of different futures, sustainability becomes a question of imagination more than one of realization, of virtual atmosphere more than lived experience. Harun Farocki’s insistence on materiality – of the images as well as of the processes creating them – becomes entangled with questions of sensibility here: How is sustainability made ‘sensible’ in and through virtual renderings? In the intersection between virtual and real spaces, the atmospheres of a space simultaneously existing and hypothetical become layered on top of each other. The vision of virtual renderings – afforded by software such as CAD as well as the hardware of the computer screen or the three-dimensional (3D) scanner – becomes almost indistinguishable from the architect’s vision, neither possible without the other in conjuring yet another, more metaphorical ‘vision’ of the urban future. The active imagination in architectural writing combines concrete operativity as a tool in the construction process and a wider performativity in constructing the atmosphere of urban environments. The operationality of architectural images, then, goes beyond presenting a visual reference point, as these images ‘help to produce the building less by resemblance, than through the exchange, of visual, textual, and numerical information, an exchange that is enabled and limited by social and political institutions as well as by material processes’ (Martin, 2017: 4). While Reinhold Martin highlights the larger socio-political context of this exchange, its temporality also plays a crucial role: This exchange is not taking place at a singular moment in time, but as a continuing and continuously changing process.

Past/present: temporality and the urban environment

Architecture inhabits an ‘ambiguous position’ not just between nature and culture (cf. Hagan, 2001), but also in the negotiation of temporality. Providing architecture with the ‘conditions of possibility of thinking otherwise’ (Frichot and Loo, 2013: 1), the concepts proposed by Gilles Deleuze and Félix Guattari in their philosophical writing on architecture have been taken up increasingly in both design practice and architectural theory ⁴ over the past decades. Key to these discussions is the exploration of the potentiality of spaces yet to come – in line with Deleuze and Guattari’s (2013) suggestion that architecture is a force able to ‘assemble a new type of reality’ (p. 345). With this shift in attention comes an openness to explore architecture through its mediated forms and different methodologies, including embodied research methods and the analysis of architectural texts. At the same time, these explorations frequently focus on either the finished building or the writing about the said building (cf. Wilson, 2015), ultimately overlooking the critical force of architecture as a site-of-becoming. The affordances of digital forms of architectural writing are interwoven with their operationalization to produce (ideas of) sustainable futures. While the process of building – from the initial drawing to the creation of architectural models up to the actual construction site – is always oriented toward the future, virtual drawings are tasked with anchoring these visions in the present. Integrating the ‘existing’ environment on the proposed construction site, virtual renderings are at the same time tasked with imagining the ‘possible’ environment. The ambiguous position of virtual renderings, then, also relates to questions of time and space in the process of architectural writing. Here, I propose that it is precisely the virtuality of architectural renderings that positions their imagination of urban environments simultaneously in and beyond a specific temporality. Contingency returns here as one of the characteristics of virtual places to point to the complex negotiation of circumstances. Between the existing environment, the approved and ongoing development and the possibility of alternative visions, virtual renderings suspend urban environments between the past, the present and the future.

Approaching virtual renderings in their specific socio-political context highlights this suspended temporality: As part of the larger effort to turn Amsterdam into a sustainable city, the municipal development plan ⁵ for Buiksloterham currently estimates the construction of 8575 apartments over the course of 13 years (ending in 2030). While virtual renderings of course rarely visualize neighborhoods under construction, the extensive timeframe of the development plan pushes the urban environment envisioned here even further into the future. Visualizing speculative futures becomes entangled with imaginations of the past – with an emphasis on the rural ‘as a repository for ways of life regarded as simpler, slower-paced and more rewarding, natural, authentic, meaningful and healthy’ (Taylor and Cairns, 2024). As notably the only highrise buildings right on the water, the two towers of The Urban Green Village extend the green riverside into the vertical sphere, both growing and overgrown with a variety of plants. Similarly, references to the urban and industrial present of the north of Amsterdam are replaced with those of a rural past: instead of cargo ships, the virtual rendering features traditional fishing boats on the calm and undisturbed water of the river. However, the references to the rural past should be understood as more than mere nostalgia. In their blending of different – partly real, partly imaginary – temporalities, virtual renderings are not only different from other architectural media but also other visualizations of alternative futures. To present these sustainable architectural projects as a viable and possible option for how the urban environment could and should be (re)constructed, the contingency between the past, the present and the future is crucial. Projecting the imaginary of a more natural, more authentic, more connected past into the yet-to-be-built urban future, these virtual renderings explore how we could think about and relate to our surroundings in a changing world.

‘Drawings and visualizations are architecture in their own right’, Eric Baldwin (2022) proposes. Yet, architectural drawings and visualizations contain a link to architectural realization that is simultaneously prescriptive and speculative. What makes these immaterial elements – ranging from computer-generated images (CGIs) to virtual renderings and augmented reality applications – particularly productive as research objects is the subjective nature of the atmosphere created in and through them, an atmospheric imagination of sustainable futures embedded in a ‘field of negotiation, tension and ambivalence’ (Degen et al., 2017: 15). The proposed location for ReGen Villages in the Netherlands is close to the city of Almere, on land that was reclaimed in the 1960s. Located 7 m below sea level and currently predominantly used as farmland, the environment visualized in the virtual renderings necessitates not just the construction of the buildings but also of complex ‘natural’ infrastructures, able to withstand and counter potential flooding. This includes new canals and ponds as well as the surrounding forests. To allow for what James Ehrlich, founder of ReGen Villages, frames as ‘connect[ing] a neighborhood the way it’s supposed to be connected, which is around natural resources’ (Peters, 2018), then, means very much developing a landscape – despite the seeming ‘naturalness’ of the design. For instance, the virtual renderings, visualizing the ‘village’ both from a bird’s eye perspective and from the ground, draw the attention to water as both environment and infrastructure. Connecting the different houses and their individual boat landing stages to each other, the seemingly ‘organic’ waterways form a crucial part of the design. Particularly considering the positioning of ReGen Villages as replicable and scalable across different settings – and their presumably very different conditions – the assumption of nature as equally replicable and scalable becomes palpable. In their discussion of place atmospheres, Degen et al. (2017) point to a ‘universalism’ running through imaginations and representations of urban places, which in the case studies discussed here becomes entangled with shared imaginaries of universal natures.

Arguably, the conviction of this visualization is also based on the referentiality of these virtual renderings to other established representations of landscape. As the first of the ReGen villages to be (potentially) developed, the different perspectives afforded by architectural software as well as the landscapes rendered through them appear to follow the tradition of Dutch landscape paintings. Imagining neighborhoods based on and connected through water as infrastructure and environment in this regard also situates these virtual renderings in an imaginative temporality between the rural past and the technologized future – yet both informed by the climatic change of the present. Similarly, the virtual renderings for The Urban Tree Village play with temporality through visual references. Highly stylized, in particular the interior renderings of the architectural project conjure a comparison to the 1960s through a color schemes favoring vibrant hues, the physical appearance of the human render ghosts dressed in patterned A-line dresses and colorful suits, and the interior design itself between mid-century modern furniture and space-age shapes. More than just an aesthetic choice, connecting the imagination of future ways of living (together) to visualizations of the past could also be understood as part of a larger political agenda. For Amsterdam, particularly, the 1960s represent a crucial turning point in urban planning – and in creating an urban environment prioritizing shared public spaces (cf. Verstrate and Karsten, 2011) and bicycles instead of cars (cf. Verlaan, 2021). Both of these decisions are deeply connected to both the literal and figurative natural climate of the city then and now, as well as the municipality’s current ambition to become an emission-free city by the year 2050 (City of Amsterdam, 2020). Visually referencing earlier epochs of urban change like the 1960s thereby also underlines the seeming viability of the solutions envisioned in the virtual renderings discussed here. Equating the challenges of the present – especially as it relates to both protecting and producing nature(s) – with the solutions of the past emphasizes the promise of the sustainable urban environment to be realized through architectural projects like ReGen Villages and Urban Tree Village.

Perceiving virtual environments in parallel to ‘unmediated reality’ (Murphy and Skarbez, 2020) emphasizes how the production of nature(s) in these virtual renderings is both tied to and independent of specific settings. Different from virtual environments created for other contexts – gaming, for instance – the negotiating of spatial presence at a given moment in time takes on further meaning when applied to architectural design. ‘As with any mediated spatial presence, you still know that you’re not really ‘there’, since the ‘there’ isn’t a physical place’ (2022), Dooley Murphy and Richard Skarbez write about experiencing presence in virtual environments. For the virtual renderings of sustainable building projects discussed here, however, this becomes more complicated: the ‘there’ might not be a physical place yet, but it represents a physical place to be in the future.

Space/speculation: the ambiguity of the construction site

Whereas ReGen Villages has already found – and presumably acquired – a construction site in the municipality of Almere (a few kilometers south of Amsterdam), The Urban Tree Village remains fully speculative at the point of writing. Without a definite construction site, the building therefore relies entirely on shared imaginations to simultaneously publicize and fund the idea of residential space ‘connected to sustainability, connected to each other, connected to the future’ (2021). However, the key image highlighted across different websites, including the official project website and the portfolio of the architectural firm behind the design, places the building nonetheless in the full environment of a neighborhood. Stacking different building blocks with community spaces on top of each other, the virtual renderings position The Urban Tree Village at the same time in a concrete and an abstract space. While key visual markers in the virtual renderings – a cycling bridge, for instance, as well as the river itself – reference the increasingly developed (and gentrified) neighborhood Buiksloterham ⁶ in Amsterdam Noord, the construction site itself does not exist. Rather than positioning the design in an actual (or actually available) location, the virtual rendering represents an alternative way of building – and ultimately living – through and beyond the design in a more abstract way. And yet, as this section will argue, these visions remain ambiguous both in their relationship to existing spaces and their commitment to actualizing these imagined futures.

As a conceptual approach to future ways of living, ReGen Villages emphasizes the role of software solutions in creating sustainable ‘resilient neighborhoods’. As an international project currently in its initial funding phase, the emphasis on virtual simulations underlines the connection between architectural writing, technology and imaginations of green futures. Crucially, this eco-technological ideal is thought in global dimensions: As the ‘integrated and resilient neighborhoods that power and feed self reliant families around the world’ (ReGen Villages, 2022), the ReGen Villages are (to be) situated in the Netherlands, the United States, Sweden and the United Kingdom via their national holdings. The virtual renderings available to prospective tenants, however, do not reflect potential differences across these settings. Instead, the architectural design is situated in a somewhat Dutch, yet also somewhat generic landscape. For special occasions, these ‘general’ renderings are supplemented with visual markers to reference a ‘specific’ location. For instance, a virtual rendering of ReGen Villages presented at the international horticulture exhibition Floriade in Almere, The Netherlands, features the (reconstructed) visual landmark Almere Kastell in the distance behind the houses and botanical domes of the eco-village otherwise depicted before an open horizon. Beyond the perspective impossibility of this specific view – based on the currently proposed location for the construction site in Almere – the disconnection between the built environment and the natural environment becomes notable. While constructions like Almere Kastell in this example function as markers of specificity in the spatial grounding of the project, the virtual renderings propose a generic and generalizable nature (including trees, paths, ponds) across these different locations. In other words: virtual renderings not only embed architectural design in nature, but also transform nature in the process. Or, maybe more provocatively, nature can be made to transform in a ‘blueprint approach’ similar to the technical drawings discussed above.

At the same time, this seeming flexibility does not just apply to these visualizations but also to the inherent nature of virtual renderings themselves. Based on original models and sketches as much as on pre-existing databases, virtual renderings allow for continuous changes and adaptations to architectural design. The official brochure for The Urban Tree Village (2022) highlights the potential for a change depending on the input of other stakeholders: ‘Once The Urban Tree Village has found a location, the design process is planned. We believe it is important that everyone is actively involved and has a say’ ⁷ . If virtual images ‘situate users in space both within and beyond the boundaries of the screen’ (Feiersinger et al., 2018: 7), their potentially continuously changing realization complicates a sense of spatial grounding of urban imagination. Especially in the context of larger municipal redevelopment plans toward more sustainable building and living – with Amsterdam as one of 100 European cities committed to become climate-neutral and smart cities by 2030 – it becomes nearly impossible to talk about urban environments without speculating about what might become of them. On one hand, virtual renderings allow for the visualization of urban futures beyond the status quo – and beyond current and currently deemed ‘realistic’ plans. On the other hand, the inherent vagueness in the absence of a clear setting complicates the realization of these visions. Again, the technology behind virtual renderings plays an integral role here: Rather than necessitating the (manual) drawing of all individual elements, CAD allows for the integration of existing datasets. Specifically for architectural projects functioning as ‘lighthouse projects’ – like the examples discussed here – these existing datasets provide the literal ‘surrounding’ of the design by visualizing natural and built environments from a set catalog.

In other words, virtual renderings situate specific designs in generic environments – as becomes noticeable in the repeating patterns and natural elements in the renderings for ReGen Villages. Rendered from a bird’s eye perspective, the perfectly symmetrical field strips, alternating between hues of green, yellow and purple, are disrupted by a seemingly organic system of canals that flows between the clustered buildings. Linking the virtual renderings to the spatial location of Almere – the ‘youngest’ city in the Netherlands, built entirely on reclaimed land – further highlights the ambiguity of urban visions informed by and mediated through technology. Arguably, this repetition of the same ‘natural’ elements and their ‘natural’ placement in highly controlled and constructed landscapes, is both afforded and complicated through CAD. Through an interview with an unnamed visualization artist, artist and writer James Bridle (2013) comes to call this approach to continuously reused and recycled images ‘lorem ipsum architecture’ – ‘placeholder things and people, pulled at random from vast databases to populate imaginary places’. In conceptualizing future urban environments as more sustainable, more green, and ultimately more ‘livable’ spaces, this placeholder status of the rendered environment becomes problematic in grounding sustainable architecture. Even beyond the realization of the building, the spatiality of architecture in ever-changing environments adds another layer of speculation. From the perspective of Amsterdam – with statistically 189.3 rainy days per year, and 5.7 months per year of overcast skies – the spatial setting of the virtual renderings discussed here becomes somewhat unrealistic. Positioned under ‘perfect skies’ and referencing an ‘evergreen’ rural idyll, ReGen Villages and The Urban Tree Village construct an idea of nature that is not only profoundly idealized but also notably replaceable. London, Almere. Virtual, Real.

The question of replaceability in the negotiation between the physical and the virtual space of the city also takes on another dimension: among ‘examples of architecture and its virtual substitutes, replacing real spaces, only nature remains impossible to replace with the computer substitutes – yet’ (Skaza, 2016: 177). However, this is precisely what both ReGen Villages and The Urban Tree Village appear to be doing in their emphasis on designed and technologized landscapes – independent of the actual, existing environmental conditions of their prospective, or rather potential, construction sites. Pushing this even further, the emphasis on databases in creating virtual renderings contributes to an idealization of ‘nature’ that does not necessarily contribute to approaching environmental concerns. While larger databases allow for a filtering of plants based on visual as well as geographical and functional characteristics, it remains questionable whether these are actual factors in the decision-making process of architectural practitioners.

Conclusion

Speculation is inherent in the visualization of architecture, as Antoine Picon underlines: ‘There is no architectural design without some margin of indeterminacy that allows for different paths to be followed. Usually only one will be realized’ (Picon, 2004: 115). In a similar line, Reinhold Martin calls this ‘a certain amount of give and take built in’ (Martin, 2017: 2). That the translation from visualization to realization is not necessarily straightforward also becomes visible in a range of articles comparing and contrasting renderings of buildings to their realized forms – often with less convincing conclusions. ⁸ Indeed, it is one of the characteristics of architectural writing – architecture as writing – that in the design process a variety of different outcomes is imagined, designed and discarded. Of the possible futures written in this way, only some will actually be built. The affordances of digital technologies to render objects from different angles and in different variations, as well as the possibility to return to a previously discarded ‘draft’, is arguably easier than with non-digital models, and add further to the operationalization of virtual renderings. At the same time, the explicit focus of this article on the virtual renderings of ReGen Villages and The Urban Tree Village – two building projects that have not been approved yet, that have not been funded yet, that have not been constructed yet – highlights this speculative potential even further. Pushing the unique positioning of virtual renderings in and beyond temporality and spatiality further, their speculative character plays with the potential to imagine alternative urban futures. As an engagement with possibilities for shaping the city, virtual renderings allow for a visualization of (urban) plans that might – and likely will – continue to change.

The emphasis on Amsterdam grounds the exploration of virtual renderings in one and the same socio-political setting. At the same time, Amsterdam can be understood as representative of the changing role of governance and expertise in urban development (cf. Raco and Savini, 2019), highlighting the complex connections between private, public and municipal agendas in the imagination of urban futures. At the same time, the global appeal and ambition of both ReGen Villages – as a software-centered and supposedly scalable approach to construction of new neighborhoods – and The Urban Tree Village – as a lighthouse project countering the ongoing development of an urban neighborhood – already point to the significance of this discussion on a larger scale. With international initiatives like the aforementioned European Union mission to create ‘better lives for citizens, their children and the planet’ ⁹ through sustainable urban planning, the ways these visions are drawn on and constructed in individual and private projects becomes political as well. In a comparative view, both the design and technology of circular building and living toward climate neutrality become somewhat generic as well – as do the environments created through these urban approaches. As a starting point to the multiple possibilities of what ‘greening’ the city means in both virtual and real spaces, the discussion of the two case studies here has the potential to function as a point of comparison to other examples both within and beyond the Dutch context. The play between spatially grounding and abstracting urban settings is relevant to nuance our understanding of nature and ‘natural’ environments. In the tension between original built environments and generic natural environments, the complex operationalization of virtual renderings to both imagine and shape urban environments sustainable and sustainably becomes increasingly visible. Just like Bridle’s render ghosts, virtual renderings of urban environments arguably reside at a place of in-between: Between virtual and real, between present and future, between space and speculation.

The focus on the speculative potential of digital renderings of urban environments allows for an expansion of contemporary conceptualizations of ‘the city’ (cf. Hinchliffe and Whatmore 2009; Mitchell and Casalegno, 2008; Vehlken, 2019). Visualizing the idea of a space not-yet-built, yet-to-be-built, potentially never-built, contains a multitude of speculative temporalities – particularly as it comes to the imagination of environments. If urban imaginaries are ‘not just “matters of the mind”, but also manifest and find expression in lived urban space’ (Lindner and Meissner, 2019: 1), cross-mediated architectural writing allows us to trace the potentialities of both architecture and nature to image and produce more sustainable futures. In this article, I am consciously employing the term ‘speculation’ rather than drawing on the dialectic of utopia/dystopia: instead of an inevitable outcome, virtual renderings allow for an engagement with possibility, for architectural practitioners as well as for the current and future inhabitants of the urban environments envisioned here. At the same time, the threefold characteristics of virtual places as atmospheric, contingent and ambiguous point to complexity of speculation as a specific type of imagination. In their openness to change and adapt, to reuse and recycle existing images and ideas, virtual renderings produce not just one but a multitude of possible futures at the same time – independent of their actual realization and realizability. Here, it is precisely what makes virtual renderings productive in imagining alternatives that also makes these visions increasingly blend into each other.

This replaceability becomes even more pronounced when tracing the virtual renderings across different platforms and different architectural projects: The information brochure for The Urban Tree Village not only features the virtual renderings discussed in this article but also stock images and virtual renderings of (parts of) other sustainable building projects designed and completed by the same architectural firm. Maybe most notable among these is a rendering visualizing green terrasses, balconies and pergolas, not just overgrown with plants but as a literal forest of expanding over three floors. As with the integration of Almere Kasteel in the ‘generic’ rendering of ReGen Villages discussed above, the visualization is an impossible one: the current design for The Urban Tree Village does not feature a tiered terrace between the individual building blocks. The design for residential area Sloterdijk Kavel N, created by the same architectural firm in 2017 and situated in the west of Amsterdam, The Netherlands, does, however. Highlighting this is not meant as a critique of the architectural practitioners here, nor as an emphasis on the commercialization of designs. Rather, the repetition and recycling of both nature in virtual renderings and virtual renderings of nature across different projects emphasize the seeming generalizability and replaceability of environments. Suspended between the past, the present and the future, virtual renderings simultaneously reference shared concepts of sustainable policies as much as they produce alternative visions of nature in the urban. This becomes particularly pronounced when the practical and imagined temporality of virtual renderings is connected to their grounding in and beyond a specific spatial setting. As ideas of a green(er) past become entangled with promises of green(er) futures, virtual renderings become charged with not just representing forms of building, but more crucially also forms of living. At the same time, the speculation inherent in virtual renderings warrants a critical discussion – not just about which possible futures are actually built, but also about which futures are imagined in the first place.