As with any industry, the “Rapid” industry which encompasses 3D scanning and 3D printing has its own set of terms and lingo. Since many of those who are interested in how this technology can benefit their businesses are not necessarily familiar with these terms, we’ve put together the following glossary to help navigate the jargon:
| Term | Definition |
| 2D Drawing | A technical illustration containing two dimensional views of an object from multiple viewing directions, used in engineering and manufacturing. |
| 3D Printer | A machine that fabricates objects through the deposition of infinetesimal layers defined by 2 dimensional cross sections of a 3 dimensional CAD model. |
| 3D Printing: | The action or process of making a physical object from a three-dimensional digital model, typically by laying down many thin layers of a material in succession. |
| 3D Scanner | A device that analyses physical objects through the use of optical triangulation in order to to collect data on its shape and possibly its appearance (e.g. colour). The collected data can then be used to construct digital three-dimensional computer models. |
| 3D Scanning: | The acquistion of the data that defines the shape of a physical object. This is usually accomplished by some type of optical measuring or scanning device. The resultant scanned data is typically output as point cloud or polygon mesh. |
| Accuracy | The deviation between a measurement and the actual value. This characteristic of a measurment system is usually defined by a certification process that invovles the use of artifacts that are traceable to a national standard. |
| Auto-Surfacing | A method by which a CAD model is created by “skinning” a polygonal mesh with surfaces. Typically used in modeling of organic or sculptural shapes. May not be useful for all types of parts, particularly mechanical objects. |
| CAD | Computer aided design. A method of product design that employs the use of computer graphics. |
| CAM | Computer aided manufacuring. A type of software product used to program CNC machine tools through the use of CAD models. |
| CMM | Coordinate measuring machine. A device used for dimensional measurement and inspection of manufactured parts. May be manual or computer driven (DCC). |
| CNC Machining | Computer Numerically Controlled machining. The machine tool is programmed using CAM software to generate the G-Code that defines the shape of the final manufactured part. |
| Design Intent | A method of reverse engineering where the user attempts to develop a 3D CAD model which matches the original designer’s intent, based upon a 3D scan of an existing part. A best effort is made to adjust actual values to their nearest standard value and eliminate manufacturing defects from teh final result. This is in contrast to an “as-is” methodollogy which attempts to match the original part as closely as possible, defects included. |
| Direct Modeling | A type of CAD system that allows the user to directly edit 3D geometry, as opposed to editing sketches and features as in a parametric sytem. |
| Feature Based Model | A feature based model is composed of primitive geometric features, trimmed surfaces, fillets & radii. Geometry is developed using traditional solid modeling techniques such as sketching and extruding, using the underlying scanned data as a reference. Original feature geometry may be extracted after import into customer CAD system. The only difference between a feature based model and a parametric model is that the Parametric model contains model history, and the feature based model does not. |
| GD&T | Geometric Dimensioning and Tolerancing (GD&T) is a system for defining and communicating engineering tolerances. It uses a symbolic language on engineering drawings and computer-generated three-dimensional solid models that explicitly describes nominal geometry and its allowable variation. |
| GR&R | Gage R&R, which stands for gage repeatability and reproducibility, is a statistical tool that measures the amount of variation in the measurement system arising from the measurement device as well as the operators taking the measurement. |
| Hybrid Modeling | A hybrid model will contain characteristics of both a Feature Based Model as well as a Rapid Surface Model. It is developed using a variety of techniques in order to develop a model that has both mechanical as well as free-form or organic geometric features. |
| Injection molding | The shaping of rubber or plastic articles by injecting heated material into a mold. |
| Parametric Model | A parametric model is composed of primitive geometric features, trimmed surfaces, fillets & radii. Geometry is developed using traditional solid modeling techniques such as sketching and extruding, using the underlying scanned data as a reference. Entire model history is transferred into Solidworks upon completion in order to facilitate future design changes. |
| Photogrammetry | The use of photography in surveying and mapping to measure distances between objects. In the metrology world, reflective targets, coded targets, and scale bars are used in conjuntion with specialized software in order to accurately measure the location of specific points within a working volume. |
| Rapid Prototyping: | Rapid prototyping is a method used to quickly fabricate a scale model of a physical part or assembly using three-dimensional computer aided design (CAD) data. Construction of the part or assembly is usually done using 3D printing or other similar additive manufacturing technology. |
| Repeatability | the variation in measurements taken by a single person or instrument on the same item, under the same conditions, and in a short period of time. Athough often used interchangeably with accuracy, repeatibilty refers more to the consistency of a measurement as opposed to its deviation from the actual value. |
| Resolution | In regards to 3D scanning, the resolution of the scan refers mainly to the point density of the resultant point cloud, and is related to the smallest geometric feature that the system can resolve. Although resolution can impact accuracy, particularly on small features, it is a separate characteristic of the device from both accuracy and repeatability. |
| Reverse Engineering | The development of 3 dimensional CAD models from scanned data. |
| Solid model | As opposed to a 2D drawing, or surface model, a solid model is comprised of a fully closed volume of surfaces. This model can be generated in CAD via traditional modeling techniques, such as extrudes, lofts and sweeps, or from more unconvetional methods such as rapid surfacing. |
| STL file | Surface Tesselation Language. An STL file is comprised of a polygon mesh that defines the shape of a three dimensional object. It is the original file format used to drive 3D printers, and is also widely used in 3D scanning as an interim step between the raw point cloud and the final CAD model. |
| Surface model | A type of 3D CAD model that may or may not fully close a volume. The surfaces in this type of file are generally NURBS: Non-uniform rational basis splines. |
| Point Cloud | A point cloud is a set of data points in some coordinate system. In a three-dimensional coordinate system, these points are usually defined by X, Y, and Z coordinates, and often are intended to represent the external surface of an object. Point clouds may be created by 3D scanners |