cardboard chair Project

I designed the Torus Chair for a project in Fall of 2021. We were tasked to design and build a chair for our partner that caters to their needs and wants. The chair must be made with no more than 5 sheets of 4 by 8 feet of cardboard, and no adhesives or fasteners are allowed in its assembly.

TORUS CHAIR

torus chair

client
interview

My partner, Sarah, wanted a chair that was both ergonomic and aesthetically pleasing. She has scoliosis, and working long hours on her laptop often causes severe back pain.

PROBLEM SPACE

PRoblem Space

THUMBNAIL
SKETCHES

I drew thirty quick thumbnail sketches detailing different ideas, such as aesthetics, functions, and mechanisms, that I could try in future sketch models. These sketches were guided by earlier objectives I had come up with.

SKETCH
MODELs

I created 12 sketch models to test out some of the mechanical and design ideas of my thumbnail sketches. I was able to find out which ideas were feasible and which ones were not.

IDEATION

MANiKIN

In order to better understand Sarah’s dimensions, proportions, posture, and seating line, I made a 1/6 scale manikin using her measurements. The manikins also account for the loose clothing that she often wears; tolerances were also added for comfort.

90 DEGREE
SEating
line

The first seating line I tried was a 90 degree seating line. After doing some research, I realized that a 90 degree sitting angle is not the most ergonomic nor comfortable.

120 DEGREE
SEating
line

The second seating line I tried was a 120 degree seating line. After doing some research, I found out that this seating angle is much more ergonomic than the 90 degree seating angle; however, when compared to the next seating line (135 degrees), this seating line is still lacking. The biggest issue is how it leaves the neck at an awkward angle and position.

135 DEGREE SEating line

This seating line, the 135 degree seating angle, is the most ideal ergonomic seating angle according to my research. It alleviates pressure on the disks, and prevents people
from slouching. This is the seating line I decided to move forward with.

SEATING LINES

WAFFLING
CODE

During the ideation process, I realized that in order for my design’s geometry to not be constrained by the cardboard sheets, I had to first create the geometric form (3D model) before finding ways of creating it by waffling cardboard panels. I decided waffling was the best method based on my sketch models. I found that it allowed for the greatest detail and freedom in representation of 3D surfaces for the 2D-like cardboard sheets. Waffling also requires a high degree of precision, which is why I decided to use software to design it.

waffling code

Shown the the right is the grasshopper code I used to waffle my structures. On the left, I loaded in a curve for the cut frames to run along and the 3D model of my chair. I can also use the contour tool to the same effect; however, the countour tool only works at perpindicular angles! Not shown here is code that allows for the calculation of the intersections and intersection points. I ended up not using it because it would frequently break.

WORKFLOW

physical Model

My first concept was an extension of the torus sketch models I made. I adjusted the angle a little bit so that the torus allows the person sitting in it to sit at a 135 degree angle. The purpose of this concept model is to see how well a torus shape can be represented using perpendicular panels. This concept model had issues with sturdiness and shearing, which I fixed with later iterations. This concept ended up being the concept I used for my final models.

Concept diagram

I did not want any dimensions to be arbitrary. All dimensions and angle were created using the golden mean and a protractor. In order for the user to sit at a 135 degree angle, the torus must sit at a 125 degree angle from the ground. By using the template on the right, I was also able to draw important dimensions such as the distance between circles, bucket length, height, width, and more.

concept Rendering

concept 1

physical model

This concept played with the idea of using radial panels for rigidity. Although I did not use this design, what I learned while making it regarding angled panels and rigidity was very relevant to my final model.

concept diagram

Using the seating line template on the right, the basic structure of this chair was created by creating two curves: one from the top of the neck to the arms and then the ground, and one from the top of the neck around the butt and to the ground.

concept rendering

CONCEPT 2

concept 2

physical model

For this concept, I wanted to see how detailed of a surface I could make with just interlocking panels. I also wanted to find out what distances were required between panels for a geometric form or surface to show. This concept was unfeasible due to material constraints. However, the things I learned while making this model, particularly concerning making 3D surfaces, were very useful for my final model.

concept diagram

I used different golden ratio circles line up the posture and create a seating line. I then created 2 more curves: one supporting the arm, and one in between the two. I then lofted these curves on Rhino to create a seating bucket.

concept rendering

CONCEPT 3

concept 3

angled panels

For this concept refinement model, I played with how much I could angle the panels. Angle the panels decreases shearing and allows for a more stable construciton.

angled panels

I found out that angling both axis's of paneling was not a good design decision. Although it looked great in some angles, the design's inner geometric details often became submerged. The curves that made up the inner surfaces of the chair also became flattened. I decided that the best course of action was to only angle one axis of panels for stability and aesthetics while keeping one axis perpendicular to preserve the chair’s geometric form.

preserving form

After realizing that one axis of paneling must remain perpendicular for the geometric form to be preserved, I decided to attack the issue of material restrictions. I realized that there was not enough cardboard to create the form I desired. My solution was to use thin strips to suggest the form of the chair.

refinement

seating cage

For this concept refinement model, I played with how much I could angle the panels. Angle the panels decreases shearing and allows for a more stable construciton.

Chair dimensions

For this concept refinement model, I played with how much I could angle the panels. Angle the panels decreases shearing and allows for a more stable construciton.

Creating Form

I found out that angling both axis's of paneling was not a good design decision. Although it looked great, like a blooming flower, from some angles, angling both axis's causes the inner geometric details to become submerged. The curves that made up the inner surfaces of the chair became flattened. I decided that the best course of action was to only angle one axis of panels for stability and aesthetics while keeping one axis perpendicular to preserve the chair’s geometric form.

creating form

After realizing that one axis of paneling must remain perpendicular for the geometric form to be preserved, I decided to attack the issue of material restrictions. I realized that there was not enough cardboard to create the form I desired. My solution was to use thin strips to suggest the form of the chair.

creating base

After realizing that one axis of paneling must remain perpendicular for the geometric form to be preserved, I decided to attack the issue of material restrictions. I realized that there was not enough cardboard to create the form I desired. My solution was to use thin strips to suggest the form of the chair.

testing

After realizing that one axis of paneling must remain perpendicular for the geometric form to be preserved, I decided to attack the issue of material restrictions. I realized that there was not enough cardboard to create the form I desired. My solution was to use thin strips to suggest the form of the chair.

testing

After realizing that one axis of paneling must remain perpendicular for the geometric form to be preserved, I decided to attack the issue of material restrictions. I realized that there was not enough cardboard to create the form I desired. My solution was to use thin strips to suggest the form of the chair.