Project 2

1. Modeling

• Software: Use specialized tools like Rhino + Grasshopper with Kangaroo, SOFiSTiK, Easy, or Formfinder.

• Geometry: Define membrane surface using NURBS or mesh geometry.

• Boundary conditions: Set points with fixed or cable-supported constraints (green squares in the image).

• Cables: Model edge cables as tension-only elements.

• Material: Assign membrane properties (e.g., PVC-coated polyester or PTFE-fiberglass) with isotropic/orthotropic behavior.

2. Form-Finding

• Objective: Achieve a stable form under pre-stress or gravity loads.

• Methods:

  • Force Density Method (FDM): Quick, good for concept stages.

  • Dynamic Relaxation: Iterative, accounts for nonlinear behavior.

• Output: A naturally curved tensioned shape (minimal surface) resisting loads efficiently.

3. Structural Analysis

• Loads: Apply dead load, prestress, wind (CFD can help here), and snow (if applicable).

• Analysis Type: Nonlinear static analysis due to the flexible nature of membranes.

• Outputs:

  • Membrane stress distributions (warp/weft or principal directions).

  • Cable forces and reactions at supports.

4. Cutting Pattern Generation

• Flattening the surface while:

  • Minimizing distortion (strain and shear).

  • Maintaining original dimensions in warp/weft direction.

• Steps:

  • Divide the curved surface into panels.

  • Use tools like Rhino Membrane, Easy, or GSA for patterning.

  • Add seam allowances and direction of fabric (warp/weft orientation).

Summary Workflow

Step	Tools	Key Output
Modeling	Rhino + Grasshopper	Membrane + cable geometry
Form-Finding	Kangaroo, Easy	Equilibrium shape
Structural Analysis	SOFiSTiK, GSA	Stresses, reactions
Cutting Pattern	Rhino Membrane, Easy	Fabric layout