Nano step - Learning Parametric Modelling

Introduction

Parametric modelling with Rhinoceros and its Grasshopper plugin transforms how we approach design, modelling, and analysis in civil and structural engineering. This article encourages engineers to take the first step in learning this powerful tool, which offers flexibility, efficiency, and a new level of control over complex designs. Below are three key benefits that make parametric modelling essential for modern engineering projects.

Three Key Benefits of Parametric Modeling for Engineers

1. Create Once, Reuse Many Times: In parametric modelling, geometry is developed with variable dimensions, allowing designs to adapt instantly to changes. By simply adjusting input parameters, engineers can automatically regenerate the final model, saving time and ensuring consistency. This adaptability is ideal for projects that require variations or adjustments based on evolving requirements.

2. Direct Integration with Architectural Designs for Structural Optimization: With parametric modelling, engineers can directly import complex architectural geometries for structural optimization, modelling, and analysis. This capability bridges the gap between architects and engineers, enabling seamless collaboration and helping engineers respond more effectively to design challenges and innovations in complex structures.

3. Customizable Automation with Python and VB Scripting: For those interested in further customizing and automating workflows, Grasshopper supports scripting in Python and VB, allowing engineers to perform a sequence of commands tailored to specific project needs. This flexibility lets users create their own functions and streamline repetitive tasks, further enhancing productivity and creativity.

Familiar CAD Concepts Enhanced

Rhino and Grasshopper retain familiar CAD elements: basic geometry (points, lines, curves, surfaces, and 3D objects), construction planes, gridlines, snapping, and various manipulation tools (like array, mirror, extend, trim, chamfer, extrude, and Boolean operations).

In Grasshopper (Plugin for Rhinocores), these tools are represented as "components" – functional blocks that perform specific tasks. Each component takes inputs (such as numbers or geometry), processes them, and outputs results, creating a dynamic, visually programmable workflow.

For example, the "Right Trigonometry" component under the "Math" tab will take two inputs ( two sides of a Right-angled triangle, one angle and one side) and will solve for unknown sides and unknown angles, Refer to Figure 2

This makes the interface easy to move from basic to complex with transparency.

The Grasshopper components are grouped under twelve families

The Grasshopper plugin is invoked by typing "Grasshopper" at the command line in Rhino

Components in Grasshopper

How can one remember all the components?

no need, double clicking on the Grasshopper screen, brings the input box, typing the first alphabet pops up with all components with that alphabet or complete word line "line", "curve", vector", "array", "region". Example below

Case Study 1

In the first case study, the Geometry of Belfast-type roof truss is generated, input parameter

• span

• span-to-depth ratio

• purlin spacing

Fig. 9 shows the complete scripting for geometry generation from input. The geometry will automatically change using a slider for different span and span-to-depth ratio values. Fig. 10 shows the geometry generated which can be exported as.IGES ( extension .igs) or STEP ( extension stp) for further structural analysis and design or taken ahead with the "Karamba3D" plugin for structural analysis and optimisation.

Components under Different Tabs

Summary

Parametric modelling with Rhino and Grasshopper empowers civil and structural engineers to streamline design processes, optimize complex geometries, and bring greater efficiency to their projects. Taking this first step into parametric modelling could be a game-changer in enhancing your engineering practice.

 Further Resources

University resources

1. Essential Mathematics for Computational Design

2. https://www.andrew.cmu.edu/course/48-125/IDM2/HANDOUTS_files/Rhino%20Level%201%20v4.pdf

YouTube

1. https://www.youtube.com/@individualizedproductionin7470/videos

2. Digital Design Unit – TU Darmstadt https://www.youtube.com/@digitaldesignunit

3. Think Parametric https://www.youtube.com/@Thinkparametric

IStructE resources

1. https://www.istructe.org/journal/volumes/volume-100-(2022)/issue-3/parametric-design-and-visual-scripting/

2. https://www.istructe.org/resources/training/lecture-computational-design/

3. https://www.istructe.org/resources/guidance/computational-engineering/