Sign & Digital Graphics

April '19

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34 • April 2019 • S I G N & D I G I T A L G R A P H I C S DIGITAL PRINTING AND FINISHING DIGITAL GRAPHICS dimensional models of objects or char- acters, and often include supplemental features to flesh out models with realistic details. 3D modeling software can gen- erate objects and often include painting features to add textures and color. Some programs are used for 3D ani- mation and rendering but most export to 3D printing compatible formats. If you own a version of Photoshop CC, all the tools you need are buried deep inside the program. There are dozens of other programs ranging from basic to ultra-sophisticated that model 3D objects. Here is a URL that lists the best 3D modeling software available: http:// sdgmag.ly/2zxm7. 3D Fundamentals The basic principle of 3D modeling is the structuring of the surface of an object into polygons called "vertices". The sur- face of an object can be captured using a 3D scanner or generated in 3D software. The contour of the object, consisting of polygons is "mapped" and a virtual model is generated that can be reshaped, col- ored and surfaced. The more polygons a model has, the more surface detail can be portrayed. (Figure 3) 3D Printer Formats The models data needs to be config- ured into a format that the 3D printer's software can interpret. The software arranges the data into consecutive layers. During the printing process, the model's contours are deposited layer by layer in a material such as plastic or metal by the printer's emitter heads and fused by a heating method or ultraviolet light. STL and WRL The two most common file formats for 3D printing are S T L and V R M L . STL or "stereolithography" configures single colored objects. STL is typically used with desktop 3D printers. VRML, pronounced "vermal", with a file exten- sion of WRL stands for "Virtual Reality Modeling Language" This 3D format enables color printers with more than one nozzle to emit multiple colored plastic filaments. ATMF Additive Manufacturing File Format (.AMF) is a new XML-based open stan- dard for 3D printing. AMF supports mul- tiple colors. AMF files use a compression scheme that reduces the file size of the document. Figure 3: The more polygons a model has, the more detail can be created. GCode This format contains detailed instruc- tions for a 3D printer to follow for each layer. It determines the starting point for each layer and the path that the nozzle will follow when the material is depos- ited. Proprietary Formats Some 3D printer manufacturers have proprietary formats that contain instruc- tions for a specific make and model of printer and the printer's software. Fortunately, proprietary file formats are generated from STL or WRL files so that any software that can export to these common formats can be used to create the model. Choosing a Printer There are dozens of 3D printers on the market today ranging in price from the low hundreds to the high thousands of dollars. With the price, the sizes, capa- bilities and speeds increase. Finding the best 3D printer for your situation is a matter of researching the specs and matching them to your particular needs. Here are a few questions you can ask: • Does the printer print only one color or does it have multiple-color capability? • What is the maximum size the printer can handle? • How much time does it take to print a reasonably sized object? • Are materials readily available and are they expensive? • What type of display does it have? • Does it come with modeling soft- ware? Printer Problems 3D printer can produce amazing objects, but despite everything, a seem- Things to Look for in a 3D Printer • Does the printer print only one color or does it have multiple-color capability? • What is the maximum size the printer can handle? • How much time does it take to print a reasonably sized object? • Are materials readily available and are they expensive? • What type of display does it have? • Does it come with modeling software?

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