August 22, 2016
by Chris Curran
As the experience of sourcing, creating, optimizing and printing 3-D models becomes simpler and robust, 3-D printing will find uses beyond prototyping.
Software for 3-D printing is evolving along several paths that complement and accelerate advances in 3-D printers themselves. Innovations focus on providing 3-D designs that are ready to make or modify, developing easier-to-use and less costly design tools, and turning smartphones into 3-D scanners that start the design process-to name a few.
With innovations like these, software lies at the heart of the evolution of 3-D printing. It spans the entire 3-D printing lifecycle-from sourcing ideas and designing in three dimensions to delivering formatted data to 3-D printers, and then monitoring and managing the printing process. Software defines and enables interfaces between computers and printers, drives automation, captures intelligence, and integrates processes that make the whole ecosystem hum and move forward.
As discussed in the article “The road ahead for 3D printers,” expectations run high for 3-D printing, also known as additive manufacturing. Meeting those expectations depends on the industry’s ability to pivot from rapid prototyping to printing finished products and components. Software innovation, examined in this article, is central to this pivot: manufacturing finished products demands a higher degree of automation, reliability, and repeatability. A future article will explore advances in print materials.
Software roles in 3-D printing
As noted, the role of software spans the entire 3-D printing lifecycle, starting with the designer’s idea and ending with a physical artifact. Figure 1 illustrates that software solutions are concentrated in four phases of this lifecycle:
Source: Software that allows access to existing 3-D models or the creation of 3-D models from existing artifacts; this software includes emerging libraries of 3-D models and scanning solutions
Design: Software used to create a 3-D model that is a digital representation of a physical product; this software includes established computer-aided design (CAD) solutions and newer methods for creating a 3-D model
Optimize: Software that refines 3-D models so they can be printed with accuracy, higher quality, and better results while taking into account cost, speed, materials, and other issues
Print: Software that takes the result of optimization and prepares the model for printing, and that enables the printing process so the print runs are successful
Figure 1: In the journey from idea to artifact, 3-D printing software is concentrated in four phases.
Where software can make a difference
Software is ideally placed to address many challenges facing the 3-D printing industry. Among these:
Commercial and open-source [design] libraries are providing ready-made 3-D models that users can further develop or customize.
- Commercial and open-source [design] libraries are providing ready-made 3-D models that users can further develop or customize.
- Creating 3-D models is hard: Most CAD solutions remain the province of highly trained design professionals. Even they often must acquire additional skills to work successfully with 3-D printers and 3-D printing software.
- Printers are difficult to use: Some 3-D print processes can be fussy and unpredictable, requiring considerable tinkering to get the right result. Achieving consistent results on the same printer or across different printers is also difficult.
- Yield, quality, and cost-effectiveness can be poor: Existing technology sometimes yields output that might have defects or does not match expectations, wasting material and increasing costs.
- Software and standards do not capture and transmit complex and functional system details: The technology for 3-D printing is evolving to be capable of printing complete systems that include multiple materials, integrated sensors, circuits, batteries, and so on. Most modeling software presently does not seamlessly capture and transmit all this information to printers.
The following sections describe emerging techniques meant to address each of these challenges.
Until recently, users needed to create designs from scratch; now, the rise of CAD design libraries and 3-D scanning methods means designs, or digital models, can be sourced from existing digital or physical versions of a model.
Creating finished products with 3-D printing: The role of standards
As with any emerging technology, the right standards will be instrumental to the adoption of 3-D printing, its ease of use, and its success. While the industry pivots toward creating finished products and components, standards are evolving in two key areas. One is standard file formats for exchanging product information among different categories of software and printers. The second area is standards related to the performance of materials and printers.
STL (STereoLithography) is the long-standing format for sharing design information among various CAD programs and printers. STL describes the surface geometry or the topology of the object. It does not include material or color information. To overcome these shortcomings, a new open format called Additive Manufacturing File Format (AMF) has been created. AMF has native support for color, material, lattice, and other attributes. It is an official ASTM standard designed to allow any CAD software to describe the topology and composition of any 3-D product for fabrication on any 3-D printer.
In late 2013, the National Institute of Standards and Technology (an agency of the US Department of Commerce) issued two grants to advance standards in 3-D printing. One grant is to develop a suite of integrated tools for process control and 3-D printed part qualification. The second grant is to ensure that parts produced using 3-D printing are of high quality and are certified for use. Standards that certify the performance of materials and processes will allow designers to select 3-D printing with confidence for uses beyond prototyping.
Commercial and open-source libraries are providing ready-made 3-D models that users can further develop or customize. These libraries enable users to experience 3-D printing without requiring them to learn sophisticated design software. Thingiverse, launched by MakerBot (a subsidiary of Stratasys), offers thousands of freely shareable designs to download and print-as is or modified-allowing design activity without a well-developed skill set. The Cubify service from 3-D Systems maintains a library where designers can upload, share, download, collaborate on, and eventually print designs.
Autodesk, maker of AutoCAD software, is partnering with GrabCAD, an online community of 700,000 design engineers. GrabCAD recently introduced a web-based collaboration environment called GrabCAD Workbench, which supports design sharing, viewing, and annotation-allowing designers to leverage existing designs. GrabCAD Workbench works natively with AutoCAD 360 and Fusion 360-Autodesk’s online design solutions.
Figure 2: Today’s 3-D scanning solutions generate a CAD model of a physical object so it can be used in any CAD software.
Most of the 3-D printing service bureaus, such as Shapeways, Sculpteo, Materialise, and Ponoko, maintain growing libraries of designs so anyone can easily select, configure, and print 3-D designs.
Scan an existing object
Users often have a physical artifact they would like to re-create, modify, or refine. In such cases, 3-D scanners can be used to generate a 3-D model. Figure 2 illustrates the steps involved.
[With 3-D printing], it is no longer enough to communicate just topology information.” – Gonzalo Martinez, Autodesk
The 3-D scanners use different methods and technologies-including lasers, x-rays, and various colors of lights-depending on whether they work at close, medium, or long range from the object and with small or large objects. They all generate a dense point cloud, which is the collection of x, y, and z coordinates that detail the object’s external surface. This raw data is further analyzed in the software to identify physical features and their parameters, such as radius, length, angle, and depth.
Complete systems are emerging that combine hardware and software to make generating a CAD model a seamless task, supporting the full cycle shown in Figure 2. For instance, the Matterform 3-D scanner combines an HD camera, dual lasers, a rotating platform, and analytic software to generate 3-D models. An object is placed on a rotating platform and scanned from all angles, capturing details as small as 0.43 mm. The company says it is working to enhance its software to deliver 3-D color scans for more sophisticated requirements.3 Similar systems are Go!SCAN 3D and HandySCAN 3D from Creaform, HDI from LMI Technologies, MakerBot Digitizer from Stratasys, and Sense from 3-D Systems.
Not all solutions require a 3-D scanner. Some take advantage of the ubiquity of digital cameras and generate CAD models from several 2-D photos of the object. Autodesk offers 123D Catch, a smartphone and tablet app that shoots 20 or more photographs of a person, place, or thing from every angle; the photos are then processed to generate a 3-D model.
Design software: Creating 3-D models
For more than three decades, CAD software has been the conventional approach to creating 3-D designs, or models, of products. Leading CAD software vendors have their roots in 2-D drafting. Over time, 3-D capabilities became common, allowing the design, simulation, and visualization of 3-D objects and the support for subtractive manufacturing, such as computer numerical control (CNC) machining. Vendors offering CAD solutions include Autodesk, Dassault Systèmes, Siemens, and PTC. Generally at the high end of sophistication and functionality, these solutions are tailored for engineers and other professionals. They offer wide-ranging command options and functionality appropriate to the design of complex systems and devices.
Engineers may require years of training and practice to become proficient with traditional CAD software. To engage nonprofessionals, innovators are focused on CAD solutions that are far simpler and easier to use and that cost much less. Delivering good-enough functionality in accessible packages could engage a larger pool of users in design and manufacturing and could seed a larger market of hobbyists.
“Not everyone can start from scratch. Giving them templates for product categories, such as figurines, is much better for their purposes than having them create the model on a blank canvas.” – Nancy Liang, Mixee Labs
Web browser support for 3-D manipulation and interaction has become a turning point. Initially, 3-D manipulation support in browsers required downloading a plug-in, a step too far for many users. That requirement is changing thanks to the popularity of WebGL (Web Graphics Library) for rendering interactive 3-D graphics, now an integral part of most browsers. Emerging vendors such as Mixee Labs and Dreamforge are taking advantage of WebGL to bring traditional desktop CAD functionality to the browser. In 2013, Autodesk revived cloud-based 3-D modeling software called Tinkercad for casual users. Tinkercad is a browser-based 3-D solid modeling tool that has a comparatively simple interface.
The attempt to simplify also involves giving users a better starting point than a blank canvas. “Not everyone can start from scratch. Giving them templates for product categories, such as figurines, is much better for their purposes than having them create the model on a blank canvas,” says Nancy Liang, co-founder of startup Mixee Labs. The Mixee Labs approach starts with a set of design parameters. Through a browser interface, a user participates in the design process, tweaking within the parameters. The company is also building design libraries and working with third-party designers who can use the Mixee Labs platform to deliver 3-D designs and products to customers.
To improve usability, some innovators are rethinking the interface for creating and interacting with 3-D models. Startup ZeroUI- the name suggests its minimalist intentions- focuses on people’s innate abilities to design physical objects by letting them move and gesture in front of a camera. “We’re not trying to meet the current tools head on,” says CEO Raja Jasti. “We’re offering an alternative way for all users to express their creativity and take advantage of 3-D printing.”
Innovation such as that from ZeroUI is possible due to the growing ubiquity of 3-D sensors. Apple’s acquisition of 3-D sensor company PrimeSense, Intel’s recent RealSense technology announcements, and Google’s Project Tango suggest that 3-D sensing and depth capability will become commonplace in laptops, smartphones, and tablets, laying the foundation for some radical innovations in interfaces.
To 3-D print complete products or components means contending with materials, colors, and other details beyond basic shape and topology. A key arc of innovation in design software is to include details of complete systems. “Since 3-D printing can allow electronics or sensors to be embedded during the fabrication process, the design tools should accommodate that capability and integrate those details in information communicated to the printer. It is no longer enough to communicate just topology information,” says Gonzalo Martinez, director of strategic research at Autodesk.
For instance, the Stratasys Objet Studio software lets users separate a multi-material 3-D design into discrete shells and assign a material or color for each. Users can choose among three base resins; the software calculates the resulting material options and provides a drop-down palette each time the user clicks on a shell.
Tissue Structure Information Modeling (TSIM) software from Advanced Solutions brings together the ability to design, visualize, collaborate on, simulate, and analyze 3-D digital models of tissue structures. Doctorsuse the software to model much more than a shape; they also can model the arrangement of cell layers, cell types, viscosity, and other details so the complex tissue can be 3-D printed as a complete system.
Optimizing designs for 3-D printing
CAD software is a generic modeling tool for designing in three dimensions, includinsg uses not related to 3-D printing. That means not all designs created by CAD software are ready for 3D printing and will print successfully. New software solutions help to modify designs without sacrificing functionality, akin to the “design for manufacturability” concept in the traditional manufacturing discipline.
We’re not trying to meet the current [CAD] tools head on. We’re offering an alternative way for all users to express their creativity and take advantage of 3-D printing.” – Raja Jasti, ZeroUI
The “design for 3-D printing” concept addresses a range of challenges. For example, thin sections or elements cantilevered from a vertical section can collapse or deform under their own weight during 3-D printing unless additional supports are built. Software can make the changes to add temporary supports that are removed after printing. Software can also determine if a 3-D model is watertight. Being watertight means there are no holes, cracks, or missing features that will prevent the printer from knowing what is inside the object (which is to be printed) and what is outside the object. Another important feature is to hollow out designs, so less material is used and less expense is incurred during printing.
To optimize 3-D printing, the 3-D printing service bureau Shapeways offers its Mesh Medic service. Powered by netfabb, which sometimes calls its service a “spell checker for 3-D printing,” Mesh Medic takes files uploaded to Shapeways and examines them for defects that some 3-D design software may not be able to prevent, such as holes in surfaces. netfabb reports that this automated tool repairs 95 percent of these holes, greatly enhancing yields. Similar capabilities are available from Materialise and CADspan.
Another class of software recognizes that a default printing approach will print an object as a solid-simple and strong, to be sure, but costly in time and material. Optimization software creates an internal lattice structure that optimizes both material use and print time. (See Figure 3.) The objective is to use the least amount of material that will meet the design needs for strength, stiffness, and other requirements.
Within Technologies, a design consultancy, offers optimization tools such as Within Enhance. The tool will take as inputs different parameters, including desired weight, maximum displacement, and stiffness. It will then custom design an optimized internal 3-D lattice and outer skin to achieve those goals-and output the information to a third-party printer. The netfabb Selective Space Structures software also turns solid structures into lattice structures.
Another service from Within Technologies uses the same techniques to let engineers and surgeons design and remotely print 3-D titanium orthopedic medical implants. The company provides free, downloadable software to help design the implant and send the file to a third-party manufacturer.
Figure 3: This aerospace component is designed with a lattice structure that makes it lighter while ensuring it is strong enough for the uses it is designed for.
Source: Laser Institute of America (LIA)
Software to print successfully
Most 3-D printers require time- and labor- intensive setup before they can be used, and they require regular supervision during printing projects. Software is emerging and maturing to address these usability issues. Areas of focus include preparing the model for printing (slicing), directing the printhead, self- leveling, self-configuration, and feedback for quality checking.
3-D printing software should evolve to work with existing enterprise systems
In any enterprise, 3-D printing will not be and should not be an island by itself. “If 3-D printing is going to transition from interesting novelty to legitimate manufacturing technology, then it will need to interface with companies’ traditional product and manufacturing data management systems,” forecasts Mark Thut, principal in PwC’s industrial products practice.
With 3-D printing, products can go directly from engineering and design to manufacturing and production. This direct path suggests that integrating 3-D printing with an enterprise’s supply chain, enterprise resource planning (ERP), and product lifecycle management (PLM) systems will unlock a greater proportion of its promised value, rather than being just another production technology.
Over the longer term, 3-D printing is likely to compress the idea-torealization cycle. (See Figure A.) The long cycle from marketing to realization could conceivably collapse, as many of the intermediary functions are automated, reconfigured or transformed, or deemed unnecessary. For instance, simulations using 3-D models could carry out testing for many use cases.
Undoubtedly, a shorter cycle will have an impact on the enterprise architecture and systems. The marketing, design, manufacturing, and supply chain functions have their own systems, and today they are integrated to share data across these departments. As the compressed cycle of realization takes hold, fewer systems and a simpler process will likely span the full cycle, all while capturing the necessary data to maintain compliance and to run the business.
Before a model can be printed, it must be sliced (virtually) into thin layers, and the path of the printer head as it deposits the material must be defined. The way slicing is performed can depend on the material used, the printing method, and the printer type.
Slicing software divides a 3-D design into printable layers and helps plan the path of the printhead or tool, matching the design files to the capabilities of the printer. Many solutions on the market address this need, including low-cost or no-cost options. For instance, Slic3r, an open-source, cross-platform offering, has grown in popularity partly because it is considered easier to use than earlier products. KISSlicer, a closed-source product, provides support for multiple extruders and auto- packing-a process for efficiently printing multiple parts in a single build cycle.
There are also promising developments in automation, particularly at the hobbyist end of the market. For example, the build platform must be level, which is crucial for achieving output quality and repeatability. Self-leveling is now included in new units from Printrbot.
Similarly, software is also central to using real- time feedback to improve quality. Stratasys and the US Department of Energy at Oak Ridge National Labosratory, focusing on carbon composite additive manufacturing improvements, are collaborating to develop in-process inspection methods. In-process inspection identifies manufacturing defects in real time and provides feedback upstream to initiate corrective action. The multiyear program aims to supplant or replace post- process inspection with in-process analysis and correction.
Sigma Labs has also introduced an in-process inspection technology called PrintRite3D, a suite of software and hardware products to support higher-quality 3-D printing of metal parts.
These kinds of innovations will ensure that the completion of the idea-to-artifact journey increasingly will result in high-quality, cost- effectively printed products.
Software will figure prominently in the evolution of 3-D printing; it is the glue that holds together the entire ecosystem. Printers and the materials they use are subject to relatively slow and costly innovations, and they face limits based on physics. Software offers tremendous potential to greatly enhance functionality and improve the economics.
Concentrated in sourcing, designing, optimizing, and printing, software innovation promises to simplify the experience of engaging with 3-D printing technologies and to make 3-D printing more broadly accessible. By extending support to multiple materials, multiple colors, and complete systems, the software complements similar advancements in printers and materials. Together, they form the foundation for the industry to move beyond prototyping and pivot toward printing finished products and components.
Software will make printers smarter, more capable, and more autonomous, requiring less skill and labor to operate. Software is poised to push the state of the art in 3-D printing substantially in the coming years.