Coding for 3D Part 4: Rhino, Grasshopper and Weaverbird Setup

Rhino

After doing research on how we are going to attack this series with our toolbox of resources, we are setting up our environment for exploration. Setting up the build environment is simple enough, but it is vital. Even with our build environment, there are specific subtle things we need to do for our purposes of creation. We will go through some of these items in this article while highlighting some other integral parts.

Firstly we need to download Rhino for our modeling purposes. To do so check out this link for a free 90 day trial version of Rhino. After going through the download instructions, we can now use Rhino. When I first opened Rhino, frankly I was intimidated. I have used various 3D modeling environments and software, but Rhino’s interface is a lot to handle. No disrespect to Rhino as a package as it is great, but it seems to have a steep learning curve. It has various plugins and tools ready for your disposal. Something important to remember is that having various tools is often not the best route when building anything. This is a methodology I take in terms of technical project building as well as physical product manufacturing. My goal with Rhino is to build parametric designs through coding, so I have a precise route to learning. This allows me to get to the meat of what I want to do quickly. I would not benefit from a large overview of Rhino at this point. A lot of what Rhino has tool wise does look intriguing, but we will stay focused when using it. Otherwise our curiosity may let us stray from our path to getting things done.

Download Window for Rhinoceros

The biggest advantage of Rhino is the number of plugins available for it. These plugins are the essence of utility. We will focus on two plugins for Rhino in this series. The first plugin of interest to use is Grasshopper. Grasshopper is an algorithmic modeling plugin for Rhino. It uses a visual programming language vs. a typical text-based coding language. It also gives you the ability to reference geometrical objects from Rhino. The ability to create intriguing geometry quickly and with comparative ease is the main benefit of Grasshopper.

Grasshopper Build Environment

The second plugin of choice for us is Weaverbird. Weaverbird is a topology based modeler. It gives a designer the ability to make known subdivisions and transformation operators. This plugin allows us to automate subdivisions and reconstructing of shapes. It is a great plugin due to its ability to help in fabrication as well as rapid prototyping of ideas.

Weaverbird

Something I appreciate from Rhino is how extensive the program is from just looking at it briefly. Various software packages I have used are expansive, but Rhino seems to take things to a different level. The mind of an architect is very expansive, so their tool of choice needs to have various tools within its utility belt. I am excited to somewhat learn the mindset of an “architect” through operating in this program.

For the next installment of this series, we will try to make a simple 2D parametric design that can be extruded into 3D form. I realize the importance of 2D drawing and going to the 3D level as it makes product creation much easier. It flows better and it makes the ability to iterate more intuitive. So look out for that in our next article.

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Penn State: 4D Printing with Wood Composites for Architectural Applications

In ‘Designing for Shape Change: A Case study on 3D Printing Composite Materials for Responsive Architectures,’ Elena Vazquez, Benay Gursoy, and Jose Duarte present details on customizing parts to optimize shape changing behavior. Forging straight ahead into the 4D, the Pennsylvania State University researchers delve more comprehensively into smart materials and how they are able to morph depending on user requirements and changes in the environment—whether due to temperature, moisture, or other elements.

Looking into past studies regarding the ability for building systems to become enhanced due to ‘shifting environmental conditions,’ the authors became inspired, envisioning new concepts for architectural 4D frameworks—along with embracing the concept of unpredictability within these frameworks that can be viewed as opportunities to learn. Their question, and mission, became not only how to harness such capabilities, but also how to control them as they formed a unique ‘hydroactive architectural skin system’ that would morph in reaction to moisture in the air. The materials are a 3D printed, wood-based, bio-composite. With customized settings, the team was able to study the behavior of the material, along with comparing notes to previous 4D experiments using wood.

The framework for systematic explorations in 3D printing bilayer composite materials.

“In the case of wood-based composites, 3D printing enables the design of specific patterns for layers that lead to differential swelling and then to shape-change,” state the researchers.

Six 3D printed bilayer composite samples of PLA with varying tool path geometry and their response to being immersed in hot water.

In setting parameters for 3D printing, the team used the Silkworm plug-in for Grasshopper to customize the G Code—thus establishing control not only over the nozzle, but also the printing pattern. This means being able to manipulate the fiber orientation and shape-changing dynamics. Additional identified parameters are as follows:

  • Number of print layers
  • Layer height
  • Order for active and constraint layers in the bilayer configuration
  • Road distance controlling porosity

“The 3D printing settings that we control also through custom G Code include bed and nozzle temperatures and the 3D printing speeds,” state the researchers. “Another parameter that is in play while 3D printing is the filaments used, and whether the objects are printed using a single material or with multiple materials.”

In beginning the case study, the team 3D printed some samples with PLA to have a baseline for comparing. The next set of ‘explorations’ included the use of Laywood, a wooden material made up of 40wt% wood fiber. The authors state that samples printed with Laywood offer an elongation rate of 106% if substantial amounts of humidity are present. Activators are both temperature and humidity, with the amount of time samples were exposed directly corresponding to the level of effect.

The shape changes of the six bilayer wood-based bio composite samples with 10 minute intervals for a total duration of 40 minutes.

Aware of the effect that both porosity and print angles had on activated shapes, the researchers created 175 x 75mm prototypes in the form of combined triangles. They discovered that samples subjected to humidity deformed from 70 minutes onward.

Prototype design for a hydroactive architectural skin

“To assess how the samples keep changing shape over hours instead of minutes, we recorded shape-change of prototype B over a period of 7 hours,” said the researchers.

The shape-changes of the Prototype A with 10 minute intervals, B) The
shape-changes of Prototype B with 2 hours intervals.

During their experimenting, the researchers discovered that they could change porosity levels—which allowed them to control the 4D models. They were also able to use the study parameters to control the level of transparency in the ‘architectural skins’ they created. As many other research studies before this have made note of, 3D printing will allow for the fabrication of complex geometries. In relation to this project, the authors note that many other types of material could be used in creating the architectural skin system. In noting also that single-material prototypes deformed completely when subjected to humidity, the authors suggest that in the future a multi-material approach could be more successful

“In the explorations conducted, design decisions orchestrate the interdependence between geometry -from tool path to overall form, 3D printing settings, and time, as the added dimension in the design process. Time, in this study represents shape transformation, and we argue that a systematic material exploration and computation brings us one step closer to controlling this dynamic behavior in designing for shape-change,” concluded the researchers.

“We postulate that once the shape-changing behavior is formalized through systematic material explorations, material intelligence can be embedded in parametric computer models. This constitutes a next stage in this research and can enable us to explore design variations in the computer prior to materialization. It will also allow us to create computer simulations to assess the performance of the architectural skin designs in controlling air flow, daylight and interior temperature.”

Scientists involved in 3D printing research are hard at work around the world improving and perfecting different ways to use the technology. Along with making continually new strides in software and hardware for 3D printing, the study of materials is a strong center of focus—and composites have become very popular with strengthening metals used in the process, from carbon nanotube composites to PEEK composites or trials with continuous fiber.

[Source / Images: ‘Designing for Shape Change: A Case study on 3D Printing Composite Materials for Responsive Architectures’]

Caterpillar Is a Powerful Rhino Grasshopper Plug-in for Greater Customization in 3D Printing

Bio-inspired 3D printings by (Zheng and Schleicher 2018)

Whether you are a serious 3D printing user or not, you have probably heard of Grasshopper, a popular add on of 3D modeling software Rhino. Grasshopper lets you use scripts and algorithms to create 3D models and generative designs. It is one of the quickest ways through which designers can get started with generative designs and lets you in a visual build things such as parametric designs or designs based on datasets. You may not yet be familiar with other features, however, recently outlined by University of Pennsylvania’s Hao Zheng in ‘Caterpillar – A GCode Translator in Grasshopper.’ Here, we learn more about a new plug-in Caterpillar and its ability to unleash full use of the three degrees of freedom of Computer Numerically Controlled (CNC) machines and non-traditional 3D printing. Caterpillar lets you generate Gcode from within Grasshopper. Your dataset or generative algorithm or existing model can now be quickly turned into Gcode that you can then optimize for 3D printing. This will enable people to quickly implement very creative and new 3D printing methods and techniques as well as enable the making of more non-traditional 3D printing processes.

Zheng points out what many of have noticed over time, as 3D printing users are simply not satisfied to stop and enjoy what has been supplied to them in terms of what is now traditional 3D printing in the layer-by-layer, bottom-to-top approach. For better control, Zheng postulates that users must be able to use ‘the three degrees of freedom’ – meaning X, Y, and Z and also go beyond them. More degrees of freedom and different ways of printing mean more applications are possible. The developers have added to conventional methods previously with accompaniments such as robotic arms, 3D printers that print on curved surfaces, as well as those that extrude alternative materials like wire.

For Caterpillar to do the necessary work, you must first give it the necessary data required. This means printers settings, to include many different parameters:

“Printer bed size (MM) contains three numbers (x, y, z), indicating the maximum printing size of the printer. Heated bed temperature (°C), extruder temperature (°C), and filament diameter (MM) are based on the printing material, which normally will not be changed once settled. Layer height (MM) and subdivision distance (MM) control the precision of the printing, while printing speed (%), moving speed (%), retraction speed (%), and retraction distance (MM) control how fast the printer will act when printing, moving without printing, and retracting materials. Extruder width (%) and extruder multiplier (%) together decide the width of the printed toolpaths.”

Work flow of Caterpillar in Grasshopper

Most users can just go with their default settings to be safe, but there may be some cases where you want to customize without default restriction. Infill settings must be considered too if you are slicing the model to provide infill.

For slicer and toolpath generation, there are numerous options:

  • Planar slicer
  • Curved slicer
  • Curved toolpaths for special use
  • User-defined toolpaths

Planar Slicer (left), Curved Slicer (middle), User-defined Toolpath (right)

The workflow of the GCode generator then creates toolpaths based on points based on inputted curves, and optimization occurs:

“So before inputting the given curves to the dividing component, the program will detect and separate curved toolpaths and linear toolpaths, then divide the curved toolpaths as usual and extract the start and end points to represent the linear toolpaths.”

The GCode decoder then translates text files, assisting users in further design and control through keywords extraction and model rebuilding.

Commonly-Used Gcode.

“In the future, non-conventional customized 3D printing will be highly developed for both educational and industrial purposes,” concludes Zheng. “Low-cost 3-axis 3D printers with extra toolkits can handle a variety of tasks, providing an alternative for expensive robotic fabrication.”

In 3D printing, the central theme is customization. Users can create on an infinite scale, whenever they want, rapidly and affordability. Hardware choices continue to expand with the needs of 3D printing enthusiasts around the world, as do materials. Changes and evolution in software tend to be even more sweeping—and desired—as computer programs allow us to design objects and then control printing processes. While add-ons, plug-ins, and updates are continually available, software programs drive innovations—whether in allowing more advanced bioprinting and tissue engineering, scanning, or simulation of other processes. Caterpillar makes is much easier to implement, design and develop completely new 3D printing techniques and we can not wait to see the impact that this will have.

What do you think of this news? Let us know your thoughts! Join the discussion of this and other 3D printing topics at 3DPrintBoard.com.

Printing Simulation

[Source / Images: ‘Caterpillar – A GCode Translator in Grasshopper]