Grasshopper is a visual scripting tool for creating 3D models. It breaks with traditional CAD software in that geometry is coded rather than directly created and manipulated in the viewport. The benefit of mastering this added complexity is that, well, the end result can also be highly intricate. That renders it perfect for 3D printing. Let’s take a look at when to best use scripts versus solids and surfaces.
March of the Algorithms
Grasshopper was released as a Rhinoceros add-on in 2014 and since then has gathered a vibrant community of designers, engineers, artists, and architects. It has its own user interface panel separate from the 3D viewport in which users can add functional blocks of code.
These blocks are connected, forming a node network through which data passes to generate increasingly elaborate designs. Instead of the geometry itself, only the definition gets saved, which conveniently minimizes file size, making it easier to share Grasshopper files. The final result of creating with Grasshopper is a mesh object ready for 3D printing.
But Grasshopper is not only for the code junkies out there; after a week or so of learning and experimentation, the program becomes quite intuitive because of its visual nature. And for those working with additive manufacturing technology, it turns out to be an indispensable tool for making geometry that other modeling environments could only dream of. The following are some of the main advantages of using Grasshopper.
1. Unlimited Design Freedom
Opening up the code that generates the geometry empowers you to take full parametric control. Sliders, graphs, matrices, and other input panels offer real-time feature control to make variations almost instantaneously.
This permits the creation of computational designs for:
- Organic forms and patterns. Use scripts such as Voronoi cells, Perlin noise, fractals, or plugins like Exoskeleton and Plankton to create intricate designs that mimic natural growth or mathematical qualities.
- Functionally graded objects. The outer “skin” of the object can be subdivided into panels of different shapes and sizes. Each panel can then be filled in, depending on local requirements. This allows automatic creation of variations in ornamentation, the use of multiple materials, or mechanical aspects such as density, load-bearing direction, and porosity, giving rise to so-called metamaterials.
- Function integration. By combining multiple functionalities in a single part, you can save on material, assembly costs and source multiple parts. For example, complex internal channels can be automatically generated and optimized for applications like medical growth scaffolds, fluid pumps, cooling ducts, surgical planning models, and injection molding of prototypes.
- Grasshopper-grown designs are renowned for their beautiful aesthetic. So it’s logical that we would want to wear them on our bodies. Furthermore, because Grasshopper is parametric, fashion designers can endlessly customize and tailor their creations.
- Grasshopper facilitates the creation of sophisticated lattice networks that can be used for optimally filling a volume. This can save on material and categorically improve strength versus standard infill options provided by slicer software. Lattice networks are an entire topic of architecture that can be studied on its own, but for 3D printing, “minimal surfaces” such as Schwarz and Schoen gyroids are of special interest.
2. Ultimate Parametricity
For any project requiring dimensional control of design features, parametric design is the way to go. In constraint-based modeling, as seen in SolidWorks, Siemens NX, and Fusion 360, objects are drawn, and dimensions and constraint relationships are added afterward.
Grasshopper takes a leap in that the data directly defines all geometry. Unlike a linear history tree with features stacked on top of one another, the entire visual flowchart is a multi-dimensional history, and everything, by definition, hangs together numerically.
When modeling Grasshopper, you start with a base shape or surface related to the fixed coordinate system. From there, everything is related back to the object instead of absolute coordinates. This allows complex interdependent relationships with sophisticated constraints—for example, linking features based on the center, area size, angle of a face, the closest nearby point, or creating groups based on advanced mathematical conditions.
The way the numbers can be tweaked at any time in the process gives Grasshopper its unique and limitless capability for the high-level structural organization.
3. Quick Iterations
3D design by scripting is the fastest process by far for creating repetitive design elements. By adjusting input parameters, new designs are generated on the fly. Due to the inbuilt intelligence and complete parametricity of the program, rebuilds are in most cases robust enough for instantaneous updates.
This does away with the Christmas tree phenomenon of history-based modelers, where one error causes all dependent design features down the line to light up with red orbs in error. And because all functionality is wrapped inside input-output modules, it is also less error-prone and time-consuming than traditional coding.
When it is data-driven, it can be customized. Grasshopper is a key enabler for customization to the nth degree so that product variants do not only have a few differing features, text, or surface patterns added as an afterthought but also the entire overall geometry can be altered.
From there, it is straightforward to set up interactive product customizers where the most impactful design features can be changed with sliders.
The challenge here is that the product may lose a distinctive design DNA, and there is the pitfall that the tool will dictate the design language. Therefore, together with tool-driven explorations, it is important to keep sketching on paper alongside your work to get the results you want, solicitously choose the features for customization, and curate the outcomes.
5. Ease of Use
Adopting a new 3D modeling workflow may sound intimidating, but Grasshopper’s user-friendliness is highly underrated:
- The zoomable user interface is easy to navigate and makes it simpler to memorize the location of specific design features up to the smallest details.
- The myriad of features is visually grouped in tabbed component palettes with on-hover descriptions.
- The basic premise is very simple: functional nodes with inputs and outputs that flow from left to right to incrementally build an object. This way, complexity is broken down into a series of intuitively understandable steps.
- As seen in OpenSCAD, manual line coding is possible for very advanced users but is not required.
- To keep large definitions workable, components can be grouped, annotated, and toggled on or off when necessary to work on specific design parts.
- There are online tools with powerful cloud-based servers that allow remote collaboration.
- Large definitions can be split into different interlinked files that can be opened simultaneously in a tabbed interface.
- Next to the icons in the component palettes, functions can quickly be found aided by hotkeys and command prediction.
6. Great Plugins
Rhinoceros comes with an acceptable price tag for most users, especially considering that Grasshopper is included. On top of that, it knows dozens of free plugins that are available online. Some of these include:
- Lunchbox for paneling and unrolling shapes to flat surfaces.
- Weaverbird for subdivision and fabrication preparation.
- Karamba3D for mechanical finite element analysis (FEA).
- Kangaroo for physics-based simulation, constraint-solving, or form-finding.
- Pufferfish for shape changes such as Blend, Tween, and Morph.
- Jackalope for modifiers like Bend, Flow, Maelstrom, Splop, Splorph, Stretch, Taper, and Twist.
- OpenNest for optimally grouping multiple parts for fabrication.
- Dendro for volumetric operations such as Booleans.
- Exoskeleton for thickening a wireframe into a printable mesh.
- Plankton form a library of special polygonal shapes.
- Mesh+ and MeshEdit for mesh editing.
- Fabtools for workflow enhancement.
- Peacock for jewelry design.
7. Spirited Community
A lively online community is in place and growing. Professional designers, engineers, architects, and mathematicians are available and eager to offer advice or even complete template scripts to support your project.
8. Create G-code
It is not easy nor impossible to create the G-code toolpath definitions for CNC machines or 3D printers directly from Grasshopper. This bypasses the process of “baking out” the Grasshopper model, throwing it back over the wall to Rhinoceros, to then export the STL mesh file and repair it before generating the G-code with slicer software.
An advanced feature, it deconstructs the model into polylines and coordinates for directly commanding the extruder nozzle. This permits non-planar slicing, where layers are not printed flat following three-dimensional curvatures. It is relevant for parts with upgraded mechanical properties or when layers are visible such as with special projects in concrete, clay, porcelain, technical ceramics, or glass.
An Emerging Competency
Computational design is currently one of the industry’s niches, but it is fast gaining in popularity among artists and designers. Being infused with data makes the technological world come alive with behavior, and Grasshopper is the ideal modeling tool for creating responsive structures. Being in its own category, the gaps between CAD modeling and both the design and manufacturing stage are still wide ones to cross, but an increasing number of tools and extra plugins will help you streamline the process.
Limitations such as advanced surfacing and mechanical strength of 3D-printed structures are merely growing pains of an emerging discipline and will soon be overcome.
With the advent of more advanced functionalities, third-party software integration, and customizable user interfaces, Grasshopper can become a serious contender for industrial use, as we already see in architecture, consumer products, and jewelry.
Being data-driven, it is a direct coupling to automating digital manufacturing processes that handle mass-customized production runs. Web-based tools for visualization and product configuration are signs of a dynamic and exciting future where customers and clients are empowered to participate in the design process. It is safe to say that Grasshopper is here to stay.
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