Mesh Modeling, Part 1: 3D Printer Company 3D Systems Has Geomagic, Other Software for Meshes

This article has been updated and republished 

For decades, many CAD users have looked askance at data for any purpose made from point clouds, or polygonal meshes. Despite early attempts in the 1990s at virtual reality markup language (VRML), CAD software didn’t do much with mesh data aside from tessellated displays and FEA type applications. CGI data and other emerging types, such as scan data, info from radar, satellite and drone scans, voxels, anatomical data from MRI or CT, were left to other specialists and haven’t had much foothold in the world of mechanical design.  

Mesh data can be represented in many ways:

• Mesh 
• Polygonal mesh 
• Point cloud  
• Subdivision (or subd, pronounced SUB dee) 
• Pixels/voxels 
• Tessellation 

In some data types, the points are important. In others, the connections between the points are important. 

Raster graphics assign colors to individual pixels (like a bitmap). From there it becomes easy to represent a set of 3D points in various colors projected onto a 2D screen. Computer-driven animations are ubiquitous today and used in just about every area of visual communication. CGI tools let us create and animate organic shapes from point data much more easily than using math-driven NURBS surfaces.

Finite element analysis (FEA) methods also make use of large matrices of point data. Stress and thermal analysis, though far removed from CGI, have 3D point data in common. FEA methods also are useful for design with shape optimization and generative design.

3D scans give us the capability of collecting polygonal mesh data from mechanical probes, scans using lasers, structured light, radar and even sonar. This gives us information on everyday objects we want to represent as computer models, as well as larger items, such as ships, buildings and even landscapes captured from satellites in orbit. 

Healthcare is another industry that makes use of this type of data. Computerized tomography (CT) and magnetic resonance imaging (MRI) scans record various properties for each point in a 3D slice of a patient’s body. This gives technicians a detailed map of internal organs.

3D printing also uses point cloud data. It’s increasing use in industry has made for an expanding list of materials, processes, machines, competitors and applications where the techniques can be used. 

One company has been increasingly working with all of these applications of mesh data connected to CAD and engineering. 3D Systems started 35 years ago as Chuck Hull’s vision in a lab. Hull was granted a patent on the stereolithography process in 1986. Stereolithography uses beams of ultraviolet light to cure liquid resin into solid polymers. An abbreviation for the process name became the file extension for the STL data format. Stereolithography was just the tip of the iceberg for 3D Systems, but it served as a springboard for the company to get involved in many vertically integrated businesses all related back to the collection, processing of mesh data, and additive manufacturing. 

3D Systems’ growth both in size and in capabilities has been driven in part by acquiring other companies and products. Each acquisition gave it another piece of the additive manufacturing puzzle. 

Some acquisitions that you may recognize were Alibre (CAD), Rapidform (scan-to-cad), Geomagic (a best-in-class mesh processing tool), Sensable (3D haptic stylus), Cimatron (CAM), GibbsCAM, and many others. You can see an obvious strategy at play in these acquisitions as they are all related to creation, collection or processing of mesh data or products directly created from the scan-to-manufacture process. 3D Systems doesn’t just sell the tools. They also supply services using those tools. 

Through this strategic growth and acquisition, 3D Systems has come to be a player in several industries, including: 

• Aerospace/defense 
• Automotive 
• Healthcare and dental 
• Manufacturing and design 

Let’s take a look at these industries one by one. 

Aerospace, Defense and Automotive 

3D Systems’ involvement in the aerospace, defense and automotive industries has happened in a couple of different ways. Of course, large scale manufacturers like prototypes of a design. Evolution in both materials and processes have improved the capabilities of printing metal with resolutions down to 0.0012” with densities between 96 and 100 percent.  

If you have ever tried to source a mold for plastic parts, you know what a pain that can be. Using the metal processes, you can have a printed mold cavity and core inserts within days after designing them. Or, you can 3D print wax patterns for creating complex investment or lost wax castings.  

Healthcare and Dental Applications

3D Systems’ involvement in medical applications is impressive. D2P (Dicom to print—where Dicom is digital imaging and communications in medicine) software enables health professionals to create physical 3D models of actual internal organs for visualization, diagnostic, or training purposes from actual patient scan data. This data can also be turned into virtual reality (VR) models for digital-only visualization, used again in training and diagnostics. 

Specialized hardware and software were developed for dental applications. You now see this kind of technology installed in local dentist offices, labs and clinics across the world. Dental applications turned out to be a big growth driver for 3D Systems.  

Design and Manufacturing 

Here are some of the parts that make up the 3D Systems offerings in the field of design and manufacturing: 

Alibre—Alibre still exists as Alibre Design. It was never a major player in the CAD world, but it did bring 3D Systems a lot of the necessary expertise and technology to help integrate mesh data tools and the NURBS-centric world of mechanical CAD. It was one of 3D Systems’ early acquisitions in 2011. 

Geomagic Design X – Geomagic Design X incorporates tools to collect, process and manipulate 3D scan data, as well as integrate hybrid NURBS/BREP modeling capabilities. It is useful for scanning, repairing, altering, designing, preparing for 3D print and inspection of parts. This software has been around for a long time and  long been considered the gold standard of mesh manipulation software.  

One of the primary functions of Geomagic Design X is to take scanned data and fix holes, smooth it, register disparate scans to one another and then make it CAD friendly. That’s easier said than done. When dealing with point data, success is determined by two factors: the strength of the tools and the manual effort expended to do what the tools could not. 

Geomagic Freeform can apply surface textures. That’s impossible with a typical NURBS CAD—one of the design tasks CAD just can’t handle. It’s been a problem for a long time. You can prepare a part for 3D print with a minimal support structure. Organic shapes have been an area of NURBS product development beyond the real limits of typical CAD. Organic design is much easier in subdivision modeling, but not all CAD applications have that capability. 

Haptic Devices – Sensable was an acquisition that created a 3D haptic stylus for editing 3D mesh with 6 degrees of freedom. That line of products has become the Touch and Touch X. The stylus allows you to feel the model with the stylus as it pushes or pulls on areas of the point data. This type of design skill requires a sculptor who can connect the motion of the stylus to what’s happening on the screen. It’s like using a digital Dremel tool that can add as well as remove material. If you’re adding shape to a bone model to be implanted in a patient, for example, you need to have very fine control over organic shapes. This is definitely a niche tool that requires niche skills. There really isn’t anything else quite like it. 

An articulated stylus provides haptic feedback for additive or subtractive design in 3D. (Image courtesy 3D Systems.)

Generative—Generative design is still a fairly recent development, which combines shape optimization with stress analysis. The user sets up the mechanical constraints for a part, places loads, adds material properties, etc., and the application optimizes the part to minimize weight and distributes stress. It’s no accident that the result of generative design resembles organic shapes, bones in particular, because the applications are based on bone-growth algorithms. 

Scott Green of 3D Systems predicts that in 10 years, CAD will be referred to as HAD, short for human-aided design. An example of some of the advantages of mesh file types that current CAD does not take advantage of would be the use of non-geometric properties being assigned to a volume of material. A property such as support structure could be applied to a volume to additive manufacture of low-density hybrid models, or you might apply a texture to a face. Of course, functional and implicit modeling, as well as artificial intelligence, will have to play a role in getting us there. Green believes that CAD users need to adapt to the coming technology. Learning how to direct generative design tools is becoming a requirement for real-world situations. 

 CAM—Cimatron and GibbsCAM, both are about 40 years old, merged in 2008 and were acquired by 3D Systems in 2015. The tool and die strength of Cimatron with the production focus of GibbsCAM were a great combination and addition to the additive manufacturing goals of 3D Systems. Plus, GibbsCAM has the ability to put tool paths on a mesh model.

Since we’re talking about manufacturing, we can’t leave out the printers. The printers break down into five categories: 

• Plastic  
• Metal  
• Metal casting (wax) 
• Dental 
• Jewelry casting (wax) 

Each of these categories of printers offers up to a half dozen different models to help you find something that fits the envelope size, material, process and speed that you want to work with.  

Summary 

If you’ve been working with your head buried in the CAD, look up. There is a lot to see in the world of mesh, subdivision modeling, voxels and point cloud that can now coexist with your NURBS/BREP data. Some jobs that are difficult or impossible in NURBS are easy with subdivision—think organic surface modeling. You can pass information back and forth much more easily than in the past. Even if your current CAD tool can’t deal directly with mesh data, tools exist that do and can enable you to move between 3D scanning, design, editing, prototyping, manufacture and inspection.