Bandshell

A 3D-Printed Lattice Shell Pavilion

2022-2023

Keywords
3D-Printed Building
Lattice Structure
Tools
Rhino Grasshopper
Karamba
Python Scripting
Advisor
Vanessa Costalonga
Prof. Hanaa Dahy
Teammates
Wai Man Chau
Bill Xie
My Role
Computational Design
Concept Development

Innovations
3D-Printed Fiber Integration: Combines short and long 3D-printed natural fibers in a hybrid structure to optimize material performance and reduce waste.

Acoustic Shell Design: Inspired by the human ear, the concave form enhances sound direction, blending functionality with aesthetic appeal.

Optimized Discretization and Planarization: Leverages parametric and agent-based modeling to develop efficient fabrication and assembly strategies.
Concept
The Bandshell is a pavilion proposal fabricated from 3D-printed natural fibers, integrating short and long fibers into a single structural system.

The design features a functionally optimized acoustic shell geometry with an inner lattice structure made from short fibers that carry compression forces. The thickness of the lattice adjusts based on varying compression levels across the structure. Long fibers, woven using tailored fiber placement techniques, reinforce areas under tension, reducing strain on the short fibers. The panels, incorporating long fibers, are printed as integral components of the structure. A protective polycarbonate skin is applied to shield the natural fibers from environmental factors.
Workflow & Method
Global Geometry

The acoustic shell design is inspired by the human ear, with a concave shape that directs sound toward the audience.

Form-finding was tested using Rhino Vault 2 and Kangaroo, both utilizing the same mesh and boundary conditions.

The Kangaroo version resulted in a cross-vault form, while RV2 produced a dome with the apex at the center. The dome shape, more visually compelling, was selected as the final design.

Discretization:
Approach A: Force Lines
The main goals for the discretization patterns are:
- Fit within 1m x 1m x 1.2m 3D printer dimensions
- Minimize structural impact
- Hide seams using fiber orientation

The discretization pattern was generated by remeshing the global geometry along tension and compression lines. Connected panels were planarized to ensure seamless assembly. This approach resulted in 108 pieces, with 54 unique parts, each with a planar surface for support-free printing, optimizing fabrication time and material usage.
Discretization:
Approach B: Tension Lines Only
To prevent collisions between long fibers and component connectors, an alternative discretization approach following only the stress lines was developed to avoid the long fibers being printed along or near the edge of the connectors. This resulted in 79 unique parts, with 14 long fibers printed on top for reinforcement.
Planarization:
Approach A: Edge Planarization
The initial design featured planar edges with double-curved surfaces, yielding a smoother double-curved geometry compared to fully planar pieces. However, this approach assumed continuous long fibers at the joints, which is not feasible with long-fiber 3D printing due to its inherent limitations.
Planarization:
Approach B: Surface Planarization
Agent-based modeling was used to planarize the inner shell surface while adhering to fabrication limits (1m x 1m x 1m), maintaining geometry boundaries, and preserving the original shape as closely as possible.
Component:
Build-Up
Each component's cross-section integrates key pavilion concepts: lattice structures, short and long fibers, and the architectural skin.
Component:
Connections
Adjacent pieces are connected using lap joints and overlaps in the lattice. Steel pins run through the long fibers, connection pieces, and short fibers to secure the connections.
Lattice Topology
Topology optimization is employed to balance structural performance with minimal material usage.
‍
Two strategies are applied:
1. increasing lattice density in critical areas
2. varying lattice thickness for different structural parts.
Assembly
For easier on-site assembly, components are clustered into larger pieces and pre-assembled with permanent joints for transportation. This reduces on-site assembly/disassembly efforts.