Project: LoC Grid

  • Intro
  • Technical Aspects

Information

Primary software used Python
Software version 1.0
Course Computational Intelligence for Integrated Design
Primary subject AI & ML
Secondary subject Machine Learning
Level Intermediate
Last updated September 17, 2025
Keywords

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Project: LoC Grid 0/1

Project: LoC Grid

This project focuses on developing a surrogate model to predict the structural performance of a grid system and optimize the cross-sections of its members.

Structural grid optimization, performed with Karamba3D (Authors). [Content copyright remains with project author(s). Used with permission.]

Structural elements in buildings – such as columns and beams – are typically made from carbon-intensive materials like concrete and steel. To build more sustainably, it is essential to optimize structural systems by minimizing material usage while maintaining sufficient structural performance.

This project focuses on developing a surrogate model to predict the structural performance of a grid system and optimize the cross-sections of its members. Compared to conventional structural analysis tools like Karamba3D, the surrogate model is far less computationally intensive, allowing designers to quickly evaluate and compare multiple design options.

Summary video presentation of project. [Content copyright remains with project author(s). Used with permission.]

Project Information

  • title: LoC Grid
  • Author(s): Emily Lenarduzzi, Wei Wei
  • Year: 2024
  • Keywords: neural networks, regression, classification, surrogate model
  • Topic tags: structural optimization, embodied carbon

Project: LoC Grid 1/1

Technical Aspectslink copied

Design Workflow

This project aims to assist designers in evaluating structural system performance during the early design stages. Given a structural grid and initial cross-section selection, the algorithm predicts a performance score based on utilization, deflection, material usage, and embodied carbon metrics.

Overall design workflow (Authors)
Overall design workflow (Authors). [Content copyright remains with project author(s). Used with permission.]

The algorithm is trained on a dataset generated from a parametric rectangular grid system, modelled in Grasshopper. The dataset includes the input geometric parameters of the grid system, including grid size, division, total floor area, material properties, and cross-sections. And the corresponding structural analysis outputs of utilization, deflection, and material usage.  The materials were limited to S235 steel, and cross-sections were restricted to 18 IPE variants to reduce the complexity of the design space. 

Rectangular structural grid for data generation (Authors)
Rectangular structural grid for data generation (Authors). [Content copyright remains with project author(s). Used with permission.]
Data generation workflow (Authors)
Data generation workflow (Authors). [Content copyright remains with project author(s). Used with permission.]

Machine Learning Workflow

The objective of training a machine learning model was to predict the structural performance from the given input variables without any time-consuming analysis in Karamba3D. 

A rating system was used to evaluate the performance of each grid design. Utilization and deflection ratios were maximized within regulatory limits to avoid over-dimensioning, while material usage was minimized to optimize material efficiency and reduce environmental impact. Each design option is assigned a final performance score, from zero to fifteen, representing the combined sum of the carbon ratio, deflection ratio and utilization ratio. 

Performance indexes (Authors)
Performance indexes (Authors). [Content copyright remains with project author(s). Used with permission.]

The machine learning workflow applies supervised learning techniques, where the model is trained from labelled input and output data. An essential step was pre-processing the dataset. This involved removing the invalid data points to prevent errors and normalizing the structural analysis outputs to improve training accuracy. 

Regression neural network (left) and classification neural network (right) (Authors)
Regression neural network (left) and classification neural network (right) (Authors). [Content copyright remains with project author(s). Used with permission.]

Regression was used as an initial ML technique to predict the actual utilization, deflection, and material usage values for each design option, thus avoiding the time intensity involved in structural analysis calculations. However, this technique only outputs the predicted values but did not provide any indication of the optimal solution or ranking of the solutions within the design space. 

Disproportionality of performance score classes (Authors)
Disproportionality of performance score classes (Authors). [Content copyright remains with project author(s). Used with permission.]

Classification was then used to predict the overall performance score of each design, thus providing an effective way to rank the options within the design space. The classification model showed strong prediction results (97% prediction accuracy). However, within the dataset there was a disproportionate number of samples within each performance score class, leading to skewed prediction results.

Once trained, the algorithm was intended to be integrated into Grasshopper as a lightweight component, replacing the more computationally intensive Karamba3D analysis. However, due to Python compatibility limitations in Rhino 7, integration of the surrogate model within the Grasshopper workspace remains to be solved. 

Structural optimization workflow (Authors)
Structural optimization workflow (Authors). [Content copyright remains with project author(s). Used with permission.]
technical video presentation of project

Software & Plug-ins:

  • Rhino 7 and Grasshopper for parametric dataset generation
  • Karamba3D for structural analysis
  • Jupyter Notebook for Python script development
  • scikit-learn, MLPRegressor and MLPClassifier for machine learning models