"Between the Xiang River and Yuelu Mountain, ‘Boundless’ unlocks the potential of shared resources, restructuring community warmth with minimal vertical structure—allowing homes to embrace nature, and communities to become restorative urban havens."
—Peidong Zhu

In 2021, Plot No. 048 along the South Lake waterfront in central Changsha set a record in the city’s land market, achieving a total price of nearly RMB 2.9 billion with a 49% premium, marking it as the “ceiling” of Changsha land transactions and the highest floor price to date. On this highly coveted riverside site, line+ co-founder and chief architect Dr. Peidong Zhu was invited to design Greentown’s first TOP-tier “Phoenix” series project in Changsha—Phoenix Mansion—and for the first time, translate his proprietary residential prototype, the “Boundless Apartment,” into built reality.

The project was conceived under strict market constraints, with both price and purchase restrictions limiting resources. Within this high-pressure environment, the primary design challenge was to create residential spaces that meet current needs while enduring the test of time.

Originally proposed by Dr. Zhu in 2019, the Boundless Apartment represents a systematic rethinking of high-density residential living. By employing suspended or column-free structures, it frees the façade and maximizes planar flexibility, allowing interior spaces to escape rigid functional divisions. The concept does not simply eliminate boundaries; it begins at the fundamental structural level, returning the definition of living spaces to the residents. Each household can grow organically with life stages, fostering deep engagement with both nature and the community. Since its first implementation at Phoenix Mansion, this prototype has been adapted to a new generation of high-rise residential projects, setting a benchmark for flexible, high-density living.

Greentown’s “Phoenix” series is renowned for site-specific, context-driven strategies. In Changsha, the design team leveraged the Boundless prototype to confront the inherent challenges of high-density riverside development, making the Xiang River and surrounding landscape the core driver of both architectural logic and daily experience.

01
Landscape Scarcity and Unequal Resource Distribution
Equitable River Views: 30° Optimal Rotation to Bring Scenic Access to 90% of Units

Situated along the east bank of the Xiang River, the site offers unmatched vistas of the river, Orange Island, and Yuelu Mountain. The starting point of the design challenge was how to extend these prime resources to benefit a larger number of residents.

Traditionally, prime riverside views are concentrated in front-row units, while second-row units typically overlook gardens. To democratize these coveted views, AI-driven parametric simulations rotated the towers 30° west-southwest, combined with staggered massing and strategic setbacks to minimize mutual obstruction and maximize river-facing openings for each unit. Additionally, a central tower constrained by northern height limits was removed, and the surrounding buildings were elevated in coordination, creating approximately 10,000 m² of central super-garden space.

This strategy increased the proportion of units with river views from the typical 45% to 90%, breaking the exclusivity of first-row apartments and embedding the river and landscape into the community as a shared amenity.

The central garden functions as a vibrant green heart, visually and experientially permeating the community.

The overall massing also steps back from surrounding hills, reducing earthwork, preserving natural topography, and seamlessly extending the original park greenery into the development, achieving a harmonious integration of blue-green ecology.

02
Public Experience and Sense of Belonging
Boundless Station: Reframing Community Arrival as a Resort-Like Experience

Contemporary communities often reduce living spaces to mere “sleeping containers,” eroding emotional connection and daily rituals. At Phoenix Mansion, arrival is transformed into a layered, experiential journey through terrain-driven elevation changes.

The main entrance, positioned at the lower southern edge, stretches the arrival sequence with steps, ramps, and landscape features, converting a simple entry into a deliberate emotional unfolding.

The Boundless Station strengthens this arrival experience for vehicles. Cars approach at grade via a tree-lined municipal road, with drop-off and reception areas on the first floor providing resort-like hospitality. The underground parking is partially open to landscaped courtyards, dissolving the oppressive feel of conventional garages.

The Boundless Station also functions as a neighborhood activity hub, where everyday amenities are embedded along the arrival path—parcel pick-up, temporary stops, community service points, fitness facilities, and casual meeting spaces—creating front-loaded and scenarized services that enhance convenience and actively foster neighborly interaction.

Above, a city deck offers panoramic views, defining the community’s identity within the urban context.

The infinity-edge pool serves as the visual crescendo of the arrival sequence. Seamlessly integrated with surrounding greenery, elevated platforms, and leisure spaces, it fulfills both athletic and restorative functions while acting as an emotional buffer and a social catalyst. In doing so, it embeds a gentle, resort-like sensibility into the everyday rhythms of homecoming and community life.

As a pivotal interface connecting city and community, public and private, efficiency and warmth, the Boundless Station sets a new paradigm for urban residential living.

03
Architectural Form and Urban Context
Building Ensemble: Classic Aesthetic and Contemporary Craft

Buildings along the Xiang River skyline should not merely chase trends. At Phoenix Mansion, an ensemble approach reconciles iconic expression with urban scale, balancing longevity and elegance.

As one of the most valuable developments along the Xiangjiang River, the project embraces a timeless architectural aesthetic enriched with contemporary industrial craftsmanship, shaping a collective architectural presence that resonates with the Borderless ethos.

Curved façade screens, using arched glass and expansive panes, eliminate vertical divisions, creating a “boundless screen” that directly serves 270° interior views.

Pearl-white metal lines and precise rounded edges reflect contemporary craftsmanship. Subtle accent colors on a white base produce nuanced light effects, maintaining tactile detail at close range while offering coherent volumetric presence from afar.

The riverside façade steps down from north to south, echoing the natural hillscape. North towers reach 140 m, south towers 100 m, establishing a rhythmic composition that dialogues with the cityscape, crafting a distinctive urban marker along the Xiang River.

04
Flexible Living and Interior Spatial Freedom
Panoramic Living: Structural Innovation for Spatial Elasticity

Here, structure liberates rather than limits. Corner columns are eliminated, and core-column combined cantilever structures create expansive voids at the podium, maximizing transparency and integrating the super forest park into the building’s base. Everyday life, rituals, nature, and social interaction converge seamlessly in these spaces.

Interior units gain extreme openness and adaptability, with unobstructed 270° views dissolving indoor-outdoor boundaries.

The LDKS-B integrated system breaks traditional functional walls, connecting multiple social clusters along landscape-facing fronts. Circulation encourages exploration, supporting family interaction within flowing spaces.

Balconies are expanded to 4 meters, functioning as private sky gardens that bridge outdoor and indoor living.

Conclusion: From Prototype to Living Scene

The Boundless Apartment at Phoenix Mansion marks a pivotal practice in which line+ evolved a conceptual prototype into a vivid, lived scenario. Emerging from a prime yet highly constrained urban site, it directly confronts the deep-seated challenges of high-density development. Through a quantifiable, replicable, and site-adaptable strategic framework, the project realizes view equity, spatial elasticity, and community resilience within a limited volume—positioning boundlessness as an institutionalized response to residential fairness, experiential quality, and collective sentiment in the era of high density. We believe that this reality of boundlessness can transcend market cycles, sustaining the long-term continuity of residential value.

Here, luxury is not material accumulation, but tranquility above urban noise, verdancy above urban bustle, and poetic surprise in daily life. The project bridges locality and global context, architecture and nature, and human experience and self-reflection, constructing a resilient, high-quality urban community.

Phase II will extend community nodes such as pocket plazas, enriching daily life and social encounters. “Boundless” thus transcends spatial openness—it continues to evolve as a lifestyle, dynamically growing with its residents.

Project Name: Greentown Changsha Phoenix Mansion
Design Firm: line+ studio
Principal Architect / Project Lead: Peidong Zhu
Design Team: Binmiao Li, Xiaoyu Sun, Runzhi Hu, Qian Bian, Qiqi Zhang, Qunchen Zhang, Xianghang Cai, Xiajing Duan, Zifeng Xu, Daozheng Zhang, Chensen Zhao, Xufeng Tao
Client: Greentown Group
Interior Design: LWMA / CCD / HBA
Landscape Design: GTS Lansong Design
Construction Documentation: Basis & Partners Architecture Co., Ltd.
Façade Design: Zhejiang Greentown Building Curtain Wall Co., Ltd. / Anhui Xinshiye Door & Window Co., Ltd.
Lighting Design: Starvision Lighting (Beijing) Co., Ltd.
Location: Changsha, Hunan, China
Gross Floor Area: 265,000 m²
Design Period: June 2021 – July 2022
Construction Period (Phase I): July 2022 – July 2025
Structure: Reinforced concrete
Materials: Aluminum panels, stone, UHPC, ETFE membrane
Photography: CAAI_image · LI YI