Parametric Design

Parametric Design: Formfinding with the Help of Computer-aided Geometries

Parametric design has become essential for engineers to be able to reliably plan projects such as tunnels, bridges and other structures. Parametric design describes the computer-aided generation of geometries that can be customised by changing individual parameters. Geometry is one of the fundamental principles of engineering and is used to make structures as robust as possible, taking into account shape, angle and size. Structural analyses are used to examine buildings under various loads, such as wind loads acting on skyscrapers or aircraft, or snow loads on roofs in mountainous regions. Structural engineering therefore focuses on the optimised design of load-bearing structures to ensure their stability, safety and durability.
Parametric design concept

using computer-aided geometries to optimise structures and materials

The Benefits of Parametric Design
Parametric design has manifold advantages and is beneficial for engineers, architects, builders and the environment alike. Next to improved structural performance and the resulting increased safety, there is also the design aspect that needs to be taken into account. Both the design and analysis of complex shapes can be facilitated by parametric design. Accurate designs make the construction phase less prone to errors and can optimise the choice and quantity of materials, which can save costs. Reduced use of materials and less construction waste also have a positive impact on the environment. Greater planning accuracy also leads to more precise execution and ultimately to a higher quality of the building, which has an impact on its durability. Clients benefit from lower risks and greater transparency throughout the construction process, which not only increases the longevity of projects but also overall satisfaction.

The Use of Grasshopper and Python for Parametric Design
Grasshopper is a visual programming environment that is fully integrated into Rhinoceros 3D, a 3D computer graphics and CAD application software. It enables the intuitive creation of algorithms for parametric design, structural engineering, building physics and many other areas, even without programming knowledge. The geometries generated make it an ideal tool for architects and engineers.
Python is a versatile programming language with powerful scripting functions that is ideal for optimising parametric design. Python can be used to perform complex calculations, analyse data and implement algorithms efficiently. The flexibility of the language enables the automation of repetitive tasks, which saves time and reduces the susceptibility to errors. Python thus contributes to a considerable increase in efficiency within the entire planning process. In addition, Python can be used to develop customised functions and tools that are precisely tailored to the specific requirements and needs of a project.

GhPython Component in Grasshopper
The synergy between Grasshopper and Python significantly increases the applicability and usefulness of the results. By integrating the GhPython component into Grasshopper, which serves as an interface for Python scripts, users can develop and execute custom Python scripts directly in the Grasshopper working environment. This connection enables a smooth data exchange between Grasshopper and the Python code, which significantly increases the flexibility and extensibility of Grasshopper solutions. With the help of Python algorithms, designers and engineers are able to create geometries that update automatically when individual parameters are changed. Geometric structures are thus defined algorithmically and controlled by parameters instead of creating each design element manually. In addition, structures are continuously optimised by iteratively varying the parameters in order to find the objectively best solution.
Furthermore, complex logic, sophisticated calculations and specialised functions can be implemented that go far beyond the standard functionality of Grasshopper.

Development of a Customised Fitness Function Component With GhPython in Grasshopper

General overview of the Grasshopper definition

highlighted: Python script and utilisation of the structural
elements

By using Python within the GhPython integration, a sophisticated Grasshopper component can be developed that provides a fitness function to calculate the equivalent tensile stress (Von Mises stresses) in structural elements. The development process involves writing a Python function that precisely analyses the stress ratios of the individual load-bearing elements and, in particular, evaluates the Von Mises stress as a decisive criterion for material failure. For values below 1.0, as shown in the figure above, the components are categorised as safe and stable. Otherwise, the fitness function together with the scaling factor would have to be adjusted in order to obtain relaible results.

Python script

for the fitness function

Application of the GhPython component

in Grasshopper

Parametric design concept

using computer-aided geometries to optimise structures and materials

Benefits of the GhPython Integration in Grasshopper

• Automation and efficiency: The integration automates the iterative process of design optimisation, significantly reducing the time and effort required to achieve optimal structural performance.
• Scalability and flexibility: Users can easily modify and extend the Python scripts and optimise parameters to accommodate a wide range of structural design scenarios and constraints.
• Decision making: The combination of both methods helps to visualise large data sets to make informed decisions.

Beyond technical improvements, this integration also results in substantial economic benefits such as cost savings and lower material usage, which has a positive impact on profitability. These advantages not only optimise the project results, but also offer potential clients an attractive proposition and position companies as pioneers in efficient, cost-effective and high-performance structural design solutions.