Location: New York, United States
Program: Software Development
Year: 2024
Team: Manas Bhatia, Hao Lee, Sebastian Schloesser
Manav: Posture-Based Furniture Generation
As a designer, how do you create furniture that balances ergonomic precision with aesthetic appeal? Imagine a tool that empowers you to design for any posture — no matter how conventional or extraordinary — adapting seamlessly to each user’s unique needs.
What is Manav?
Manav is an innovative Grasshopper plug-in specifically designed to generate ergonomic furniture based on human postures. This tool accommodates a wide spectrum of poses, ranging from everyday positions to extreme and unconventional ones, such as handstands or mid-cartwheel. By analyzing these diverse postures, Manav creates customized furniture tailored to the specific body configurations of users, thereby offering a harmonious blend of functionality and creativity in furniture design.
Video Introduction for Manav.
Manav provides several key benefits:
- Rapid Prototyping: Designers and manufacturers can swiftly prototype unique furniture solutions tailored to specific users or applications. This capability significantly reduces the time and effort typically associated with traditional design processes, allowing for a more agile response to user needs.
- Customized and Adaptive Furniture: The tool empowers users to generate fully customized furniture that accommodates a wide range of postures, including unconventional ones. This ensures unparalleled comfort and support, promoting a healthier and more ergonomic interaction with the furniture.
- Inclusivity and Accessibility: By adapting to various body postures, Manav facilitates the design of more inclusive furniture options that cater to individuals with diverse physical needs or disabilities. This commitment to inclusivity enhances accessibility in furniture design, making it possible for everyone to benefit from well-designed ergonomic solutions.
Who Is It For?
Manav leverages computational methods to provide a wide array of possibilities for diverse demographics. Whether for speculative or practical purposes, artistic or functional applications, this tool fosters flexibility and innovation in furniture design, accommodating various contexts.
- Furniture Designers and Manufacturers: Manav is particularly beneficial for designers and manufacturers focused on creating customizable, ergonomic, or avant-garde furniture that adapts to the unique needs of each user. By utilizing Manav, they can streamline the design process and enhance the adaptability of their products.
- Workplace and Office Solutions: With the increasing emphasis on ergonomics in workplace design, particularly in remote working environments that demand flexibility, Manav serves businesses aiming to optimize workspaces for comfort and productivity. The tool enables the creation of furniture that supports diverse working styles and body types, enhancing employee well-being.
- Healthcare and Rehabilitation: Manav is especially valuable in healthcare settings, including physical therapy and occupational therapy, where customized supportive furniture is essential for addressing various postures and mobility challenges. The ability to design furniture tailored to individual patient needs can significantly improve comfort and facilitate recovery.
How Does It Work?
Manav currently consists of three main parts: posture rigging, furniture generation, and furniture analysis.
Fig 1. Manav’s Grasshopper logic.
The posture rigging component has two distinct iterations: freeform dragging and parameterized. The past freeform dragging iteration allows for more fluid and organic manipulation of the mannequin, whereas it lacks the same level of control and user guidance. In contrast, the parameterized approach, which is utilized in the latest version of Manav, offers enhanced control over the mannequin’s movements and poses. This method allows for more precise adjustments and can be restricted in a manner that is particularly beneficial for general users, ensuring an intuitive and user-friendly experience. By highlighting both iterations, we aim to illustrate the development process and the thoughtful considerations that have shaped Manav into a versatile and effective tool for ergonomic furniture design.
Fig 2. Manav’s segmented Grasshopper structure: body, chair, and analysis.
One of the most notable features of Manav is its ability to intuitively manipulate postures and body types exclusively using Grasshopper’s native nodes, without relying on additional plugins. This design approach emphasizes accessibility and flexibility, allowing users to adjust poses and body types seamlessly within a custom-built mannequin tool. Through this tool, users can define and export detailed body metrics, integrating them directly into our furniture design modules for enhanced customization and user-centered ergonomics.
Manav is carefully crafted to meet the needs of both professional designers and general users, with a focus on balancing creative freedom and user-friendly constraints. To achieve this, we have implemented a system of strategic restrictions within the mannequin’s movement. Simple sliders provide users with straightforward control over posture adjustments, enabling them to move smoothly between poses. Meanwhile, controlled limitations on movement prevent unnecessary complexity, ensuring a clear and intuitive experience that supports a diverse user base without causing confusion.
Through this approach, Manav not only offers a streamlined workflow but also broadens the potential for application in various design contexts by adhering to core, universally accessible Grasshopper tools.
Fig 3. Manav’s posture rigging with integrated body type selections.
I. Posture Slider
Manav features global, local, and individual limb controls, allowing for a comprehensive range of adjustments. It includes several preset posture types, enabling users to utilize sliders for interpolation between these poses. For the rigging of postures, we primarily employ Grasshopper’s Line SDL node, applying various directional inputs to effectively generate the limbs and joints.
The mannequin construction initiates from the hip position — a crucial point in the torso for this project — from which the remaining torso and limbs are generated. This process resembles the growth of a tree, where the trunk serves as the primary structure, and any movement or rotation of this “parent” element subsequently influences its “child” elements. Each limb, represented by a Line SDL node, is configured with a vector input that incorporates parent vector data, ensuring that any global operation cascades to affect all subordinate elements.
Furthermore, Manav’s posture sliders interact with multiple limb configurations, allowing individual sliders to modulate several body parts concurrently. This functionality enables seamless pose transitions, such as moving from a seated to a standing position or rotating from lying face-down to lying on one side, thereby enhancing the system’s adaptability and responsiveness to user input.
Fig 4. Galapagos’ Gene Pool node enables the mannequin’s pose parameters to be integrated into different chair generation methods.
Fig 5. Posture interpolation between sitting and lying down.
II. Body Type Selection
Manav utilizes Value List and Explode Tree (BANG!) nodes to consolidate body metrics into streamlined text files, enabling efficient data organization and accessibility within Grasshopper. All body metrics are compiled into a unified CSV file, facilitating streamlined access and analysis. In support of a comprehensive and inclusive design, Manav currently accommodates five distinct body types. Users can further customize these by adjusting individual parameters or employing a body type slider, which modifies multiple features simultaneously.
This approach not only enhances personalization but also enables users to create diverse body representations, reinforcing Manav’s commitment to user-centric and adaptable design.
Fig 6. Using csvs and the Value List node, users are able to select or create different body type sets.
Fig 7. For the MVP, we provide five different body types for testing.
III. Existing surface matching
Manav also supports workflows based on analyzing existing designs. In this case, the mannequin must arrange itself to match an existing surface, so that the analysis part can proceed with the most natural posture for that piece of furniture. For this purpose, we have provided the inputs of the Manav component as a gene pool, so that it can easily be plugged into Galapagos for optimizing based on the distance of the body’s points to the given surface. Once the optimization has run and the mannequin has been correctly positioned, analysis can proceed, or another generative design can be created based on that posture.
IV. Output format
The Manav component will output every body joint as a point, every limb as a line, and also every body part’s preview visualization BREP, making it easy for the generative design process to leverage any data type that is most convenient.
Part II: Posture-Based Furniture Generation
Once we have the basic posture and body type parameters, we will be able to output them as furniture design references or put them in various posture-based furniture generators to explore different design approaches. Currently, Manav supports three generation methods:
I. Assembly furniture: Natural-form chair generated from key body points;
II. Adaptive furniture: Self-adaptable chair using evolutionary algorithm; and
III. Soft-body furniture: Stamping-molded chair following the human body surface.
Fig 8. Natural-form chair generated from key body points.
Fig 9. Self-adaptable chair using evolutionary algorithm.
Fig 10. Stamping-molded chair following the human body surface.
I. Assembly Furniture
Utilizing parameterized posture rigging in Grasshopper, we have developed several types of generative furniture, including assembled furniture.
In this initial application, we use Manav to design a chair that perfectly integrates natural form with comfort and meets ergonomic standards. The chair’s design is elegantly simple, consisting of six bars. Each bar supports a specific body position, with five of these bars designed to adjust according to changes in the user’s posture, enhancing both comfort and support. The base bar remains static, ensuring stability. Woven fabric strips not only connect these bars but also serve as comfortable contact surfaces for seating.
The parameterized posture rigging forms the foundation of this adaptive design. It captures critical ergonomic data, such as the spatial positioning of key body areas (head, shoulders, waist, hips, and ankles), to inform the chair’s geometry. Using this data, we developed an algorithm to generate three-dimensional curves that define the primary structural components, including the support bars, seat adjusters, and seat mounting nodes. These curves are anchored to a master datum point on the ground, which is projected based on Manav’s core body point. This master datum ensures balance and optimization in the structural framework, allowing the chair to deform harmoniously according to human postures while maintaining structural integrity.
Beyond the functional aspects, the algorithm incorporates aesthetic considerations. For instance, woven fabric strips connecting the structural bars are generated through an independent algorithm. This algorithm identifies points along each bar and links them using a randomized pattern within a predefined domain. The result is a dynamic decorative element that also serves as the primary seating surface, merging form and function in a cohesive design.
As the rigging adjusts to various postures, the chair’s form evolves while maintaining a consistent design language, thereby optimizing the structure for an ideal design model. Moving forward, the tool will also focus on automating documentation for manufacturing, promoting a streamlined and automated design workflow.
Fig 11.1. Posture A.
Fig 11.2. Posture B.
Fig 11.3. Posture C.
II. Adaptive Furniture
As an alternative approach to the procedurally generated chair designs, we are also exploring a design that can adapt itself to various postures. A user could use an interface to specify the ideal posture they desire, and the chair would change its configuration to the most suitable. The chair consists of two intersecting triangular systems of cushioned rods with slots, along which bungee cables are stretched. Each triangle has a fixed base, and then two rods held by arms capable of rotating around a hinge, and extending as well. The two triangles intersect with the bungee cords passing next to each other so that a comfortable area for sitting is created at the intersection of the cords. The grasshopper definition of the system uses an evolutionary algorithm, leveraging the Galapagos plugin, to identify the ideal angles and extensions of the rods to match a given posture. The minimizing fitness function calculates the distance from key points along the chair surface and their distance to the mannequin, as well as the area of intersection between the mannequin and the chair.
As an alternative approach to the procedurally generated chair designs, we are also exploring a design that can adapt itself to various postures. A user could use an interface to specify the ideal posture they desire, and the chair would change its configuration to the most suitable. The chair consists of two intersecting triangular systems of cushioned rods with slots, along which bungee cables are stretched. Each triangle has a fixed base, and then two rods held by arms capable of rotating around a hinge, and extending as well. The two triangles intersect with the bungee cords passing next to each other so that a comfortable area for sitting is created at the intersection of the cords. The grasshopper definition of the system uses an evolutionary algorithm, leveraging the Galapagos plugin, to identify the ideal angles and extensions of the rods to match a given posture. The minimizing fitness function calculates the distance from key points along the chair surface and their distance to the mannequin, as well as the area of intersection between the mannequin and the chair.
Fig 12. Adaptive Furniture.
III. Soft-body Furniture
The furniture design focuses on creating a soft body version of a chair that adapts to the user’s body, offering a modular and customizable seating experience. Inspired by the traditional Eames plastic chair, this design emphasizes flexibility and support through a responsive surface. The chair can be manufactured using methods such as custom molding or injection molding for a seamless finish. Alternatively, a metal framework can be fabricated and wrapped with an elastic membrane or fabric to create the soft surface. The metal frame ensures durability and can be easily welded, allowing for straightforward assembly and adaptability to different body types and preferences.
To achieve this design, we used a mannequin-based framework in Grasshopper, developed to map key body joints and create ergonomic curves that align with natural postures. Points like the head, neck, shoulders, torso, elbows, hips, wrists, knees, and ankles were strategically selected to define the chair’s form. These points were connected using interpolated curves that serve as structural elements, ensuring support for critical areas of the body. The curves were lofted into a seamless surface that wraps around the mannequin’s contours, creating a flexible yet supportive shell. This surface was then translated into a manufacturable design, with diagrams illustrating each step: joint mapping, curve generation, and surface lofting, providing a clear visualization of the process.
The furniture design focuses on creating a soft body version of a chair that adapts to the user’s body, offering a modular and customizable seating experience. Inspired by the traditional Eames plastic chair, this design emphasizes flexibility and support through a responsive surface. The chair can be manufactured using methods such as custom molding or injection molding for a seamless finish. Alternatively, a metal framework can be fabricated and wrapped with an elastic membrane or fabric to create the soft surface. The metal frame ensures durability and can be easily welded, allowing for straightforward assembly and adaptability to different body types and preferences.
To achieve this design, we used a mannequin-based framework in Grasshopper, developed to map key body joints and create ergonomic curves that align with natural postures. Points like the head, neck, shoulders, torso, elbows, hips, wrists, knees, and ankles were strategically selected to define the chair’s form. These points were connected using interpolated curves that serve as structural elements, ensuring support for critical areas of the body. The curves were lofted into a seamless surface that wraps around the mannequin’s contours, creating a flexible yet supportive shell. This surface was then translated into a manufacturable design, with diagrams illustrating each step: joint mapping, curve generation, and surface lofting, providing a clear visualization of the process.
Once the furniture design is generated — or if an existing furniture piece is used — the analysis starts by extracting the chair’s surface geometry. Using an optimized posture, points from the body are compared with the chair’s surface to identify areas of closest contact. These proximity zones are visualized with a gradient: red indicates areas where the chair is closest to the body, while blue highlights regions that are further away. This gradient-based visualization provides insights into how well the chair conforms to the body, identifying pressure points and ensuring ergonomic support.
For a deeper structural evaluation, the Karamba 3D plugin in Grasshopper is employed. Karamba 3D operates through two main components: the Analysis Cluster and the View Cluster. The Analysis Cluster consists of smaller submodules for tasks such as preparing the chair’s geometry, defining supports and loads, and analyzing the surface under stress. These steps allow for precise simulations of real-world conditions. The View Cluster, on the other hand, visualizes key outputs such as the distribution of loads and supports, surface displacement, equivalent stress, and the stress-to-strength ratio. By combining these tools, we can assess critical parameters like the extent of displacement due to applied loads and overall structural performance. This comprehensive analysis ensures the furniture achieves a balance of comfort, durability, and optimal design for user support.
Fig 13. Furniture Analysis.
Fig 14. Load displacement.
Fig 15. Equivalent load stress.
Fig 16. Script
The analysis cluster consists of several smaller modules, including chair preparation, defining supports and loads, and surface analysis. Additionally, the view cluster enables the visualization of various outputs, such as loads, supports, surface displacement, and equivalent stress, providing a comprehensive overview of the analysis.
- Piker, D. (2019, August 13). Inverse kinematics post #2. McNeel Forum. https://discourse.mcneel.com/t/inverse-kinematics/87440/2
- Rietveld Landscape, R. (2024a, October 31). The End of Sitting. https://www.raaaf.nl/en/projects/927_the_end_of_sitting