If you’re a regular reader of our blog, you’ll probably be well versed in raster files by now. You’ll also be aware that there is a way to turn them into vector files automatically, with the Scan2CAD software—and even that you can do so for free.
But what, precisely, is the format that you’re getting out at the end of the process? We’ll explore why vector files are compatible with CAD software, what format options are available, and the significant advantages to using them in both design and manufacturing. First, though, we’re turning back the clock for a brief look at their history.
1. Vector files pre-date AutoCAD
With its long history, you may assume that AutoCAD was the first program to implement the use of vector files. However, it was a couple of decades previous that Sketchpad, a drawing program thought up by Ivan Sutherland, enabled users to join points with lines—essentially the same technique that is used for drafting vectors today.
Since then, there has been some debate over terminology. Images within vector files are commonly referred to as vector graphics. However, it has been suggested that this term could cause confusion; some authors prefer to call them object-oriented graphics instead. But again, this has drawn criticism. It could be claimed that the term is misleading, as there exists a type of programming called ‘object-oriented programming’—and the two are not necessarily compatible.
In the end, it doesn’t really matter too much which you use; it is, however, important to be aware of both.
2. Different types of vector file are available
Common to CAD design are the file types DXF and DWG.
Drawing eXchange Format (DXF) files are native to AutoCAD, but were designed with the intention of being shared. As such, they are supported by practically every CAD program on the market—which makes them particularly useful for multi-disciplinary collaboration. The files are also simple enough to be used in CNC fabrication. However, this also means that they are not always suitable for some of the more complex entities that designers may wish to use.
Drawing (DWG) files, on the other hand, are not open-source. For use in AutoCAD they are ideal: capable of supporting 3D graphics—unlike DXF files—they also tend to be smaller in size. But when it comes to sharing a DWG, you may encounter difficulties. Some CAD programs are unable to read the file, and it is not supported by browsers.
These are the two formats we focus on here at Scan2CAD. However, they are not the only vector formats out there.
Scalable Vector Graphics (SVG) files, for instance, are some of the most well-known types of vector file formats. Most prominent amongst their features is their small file size, ensuring them highly appropriate for use on the web.
We cover more vector file types in a previous blog post; read it to find out more and get guidance on choosing the most suitable one for you.
3. PDF files can be a hybrid of raster and vector
We missed out PDF files from the previous section deliberately—and this is because, whilst they can be classed as a vector file, they may actually be a sort of hybrid, containing some raster entities too. These are images which are not compatible with CAD programs, and which are formed using pixels. Unlike any vector elements of the file, raster entities will not be scalable, and will need to undergo conversion to DXF before you can edit them properly. Luckily, the Scan2CAD software is able to convert raster entities to vectors in just a few clicks.
For design purposes, though, you will probably want to change the whole file into a format that is more compatible with CAD programs anyway. This is an extremely quick task—where you can upload your PDF, define the settings as per your requirements, and convert it to a DXF file. And by doing so, there is the option to keep or convert any raster entities, along with the vector ones.
4. Vector files are scalable
The beauty of vector files is that they are made up of lines, plotted from coordinate point to coordinate point. It is an entirely mathematical approach to drawing—but for those who dislike numeracy as a subject, this shouldn’t put you off. Rather, the format ensures that images can stay crisp and clear at any size at all: they are scalable.
This differs to the pixel-based approach employed by raster files. If you attempt to expand a raster image, it will gradually reduce in quality. This is because there are a fixed number of pixels contained within the file; the optimal size is where all outlines appear in focus. While they offer effects such as color gradation, they are unsuitable for many purposes where accuracy or scale are key.
Vector files, on the other hand, are ideal for use in design. The commonly spouted example tells of a graphic designer, who needs his client’s logo to work on tiny business cards, giant billboards—and anything in between. A raster image would prove unsuitable for such diverse requirements, but vectors rise (literally, and quite spectacularly) to the challenge.
5. Not all raster images can be turned into vector files
When attempting to convert raster files, such as TIFFs, JPEGs or PNGs, into a vector format, you need to be realistic. Not all rasters are suitable for conversion—and for those that are, some pre-vectorization clean-up may be necessary.
The conversion software is very clever, but it isn’t human. Should your image contain text, remember that the OCR technology cannot understand full words as you and I can; if you find it difficult to read, there is no way that the software will be able to.
You also need to ensure that your input image is clear enough to allow vector entities to be traced from it. Raster file types that use lossy compression, such as the JPEG format, are particularly susceptible to problems relating to low quality files. Small file sizes are wonderful for keeping used storage to a minimum, but if there are blurred lines as a result, you are unlikely to get a good vector image at the end.
Fortunately, if you’re set on getting a vector file out of your imperfect raster, there are some things you can do to combat potential issues. You may be able to improve the resolution of the image, and reduce the colors it contains. There are also options to negate the image, deskew it, or remove any holes that may disrupt lines. You can see all of our top raster effects in more detail here.
And of course, if you are able to vectorize your file, there are more benefits in store for you.
6. Vector files are easy to edit in CAD
One of the key reasons why designers and manufacturers predominantly use vector files, rather than raster, is because they contain all the information that is necessary to be used in CAD programs.
It doesn’t matter whether you’ve started out with a vector file, or vectorized a raster: you can edit it either way. You can, of course, manipulate the images in your preferred CAD software program, be that AutoCAD, SolidWorks or DraftSight. However, you need not even leave the confines of Scan2CAD for many of the edits you may wish to make.
The full editing suite includes tools that allow you to erase different entities, draw alternative or additional elements, or move them around on your screen. You can even change a line to a curve, and vice versa. Text is easily editable, too—by selecting the words you wish to change, you can type over them, hit ‘Enter’, sit back and admire your handiwork.
If you have previously converted from raster to vector, your new file will be overlayed over the original. The best way to edit it is simply by removing the raster image from sight, using the keyboard shortcut command ‘V’. This will allow you to see just the vectorized image, and thus enable you to work on it unhindered.
7. They’re ideal for manufacturing, as well as design work
Manufacturing techniques that make use of CNC routers, milling machines and laser cutters, rely on the information contained within vector files. Such instructions are simply not held within raster files, and it is therefore not possible to fabricate a product from one. However, just as you can vectorize a raster file for design purposes, you can also convert an image for CNC.
The crucial thing to remember is that CNC machines need highly accurate designs to work from. With this in mind, when designing vectors for CNC, simple is usually best. Precision is key, and while it may take a bit of time to optimize your image, you can be sure that every second will be worth it. Manufacturing is expensive business, so preventable mistakes are not only irritating, but costly too. Check out the most frequent pitfalls of designing for CNC—and find out how you can avoid them.
As previously mentioned, DXF files, in particular, are ideal for use with CNC machines. Since it’s such a popular format, you’ll find many sites offering free, cut-ready, downloadable DXF files. They allow even the least experienced manufacturer to have a go—providing you’re willing and able to pay for the materials and machine involved in the process.
For more information on the process of converting your raster files into vector, check out our post on vectorization.