Step 1 - Generative Design Framework
Design Decision 1 – Structural Grid Optimization
Design Variables
- Bay spacing in X direction
- Bay spacing in Y direction
- Beam depth
Evaluators
- Total volume of structural material
- Estimated drift index
- Open space index
Most Important Tradeoffs to Consider
- Larger cantilever roofs improve coverage but increase structural demand.
- Curved geometries improve aesthetics but require more material.
- Increasing structural support improves stability but reduces openness.
Design Decision 2 – Facade Shading Optimization
Design Variables
- Panel rotation angle
- Window-to-wall ratio
- Facade orientation
Evaluators
- Solar exposure
- Daylight availability
- Facade area
Most Important Tradeoffs to Consider
- Increasing shading reduces solar heat gain but also reduces daylight.
- Larger window area improves daylight and view quality but increases heat gain.
- More complex facade geometry improves environmental performance but increases construction complexity.
Design Decision 3 – Cantilever Shelter Optimization
Design Variables
- Roof cantilever length
- Roof curvature
- Column angle
Evaluators
- Covered area
- Material usage
- Structural stability index
Most Important Tradeoffs to Consider
- Larger bay spacing creates more open space but increases structural drift.
- Deeper beams reduce structural drift but increase material usage.
- Smaller bay spacing improves stiffness but reduces architectural flexibility and openness.
Step 2 - Generative Design Study
For this study, I selected the structural grid optimization problem to explore the relationship between structural efficiency and architectural openness. The purpose of this study was to identify a balanced structural configuration that minimizes material usage and structural drift while maximizing open interior space.
I modeled this study by using Dynamo and Generative Design in Revit. A rectangular floor plan was parametrically divided into structural grids based on adjustable bay spacing values in both the X and Y directions. Structural columns and beams were generated automatically according to the selected grid configuration.
Design Variables
- Bay spacing in X direction
- Bay spacing in Y direction
- Beam depth
Constants
- Building dimensions
- Number of floors
- Floor height
- Column dimensions
The total material volume was calculated based on the beam and column volumes generated from the structural grid system. This evaluator was minimized to improve structural efficiency and reduce material usage. For the drift index, it was used as a proxy for lateral structural stiffness. Larger bay spacing generally increased the drift index, while deeper beams reduced the drift index.
The open space index was defined using the tributary open floor area created by the structural grid spacing. Larger bay spacing resulted in greater architectural openness and flexibility.
Step 3 - Generative Design Study Results
Parallel coordinates
The parallel coordinates graph illustrates the relationship between the three evaluators and the design variables generated during the Generative Design process. It clearly shows how different structural configurations influence drift, material volume, and open space simultaneously.
All generative design
The complete set of generated design alternatives demonstrates a broad range of possible structural solutions.
The remaining choice of design after filter
To identify more practical solutions, several filters were applied:
- Open Space > 600
- Drift Index between 0 and 300
- Total Volume of Material < 200000
After filtering, the remaining alternatives represent balanced structural solutions that provide acceptable drift performance.
Drift v.s. Total Volume of material
The results show that designs with lower drift generally require a larger volume of structural material. Increasing beam depth and reducing bay spacing improve stiffness but significantly increase material usage.
Drift v.s. Open Space
Larger open spaces are typically achieved by increasing bay spacing, but this also increases structural drift due to reduced stiffness and fewer structural supports.
Total Volume v.s. Open Space
Designs with very large open spaces would result in decreasing material volume. On the other hand, smaller bay spacing increase material demand and creates more interior obstructions.
