Ultimate Guide: PNG-to-DWG File Conversion

This guide is brought to you by Scan2CAD,the market leading file conversion and editing software

Ultimate Guide:PNG-to-DWG conversion

Table of Contents

▪ Why convert PNG files to DWG?

▪ How to convert a PNG file to DWG

▪ What is a PNG file?

▪ What is a DWG file?

▪ Behind the scenes: How are PNG files converted to DWG?

▪ Using Scan2CAD to convert PNG to DWG files

You’d convert PNG files to DWG when…….you want to edit individual elements within the image

Working with PNGs is much like painting with actual paint – editing involves ‘painting over’ the original image. The image is made up of pixels, instead of vector shapes. Editing it would involve applying a filter or adjusting brightness/contrast. Singling out a single element to be edited is close to impossible.

Image source: http://vector-conversions.com/vectorizing/raster_vs_vector.html

In contrast, vector files, like DWG are much more versatile. They allow you you to edit individual elements within the image. You can change colors, resize a particular object within the drawing, move elements around, copy objects into other drawings, and more. It is this versatility that makes DWG vector files invaluable to CAD work.

PNG (raster image)

DWG (vector image)

You’d convert PNG files to DWG when…

PNG-to-DXF conversion comes in handy when you have a stack of hard-copy images, or a folder full of PNG images on your computer that you’d like to digitize. Converting to DXF allows you to reuse parts of older drawings in modern formats.

For example, a group of architects working together can reuse certain drawing objects, like doors or windows in new projects. They can also share the floorplan with interior designers, electricians, building contractors, and others.

Vectors are also scalable, meaning that you can resize a vector drawing as many times as you wish, without any loss in quality.

….you want to edit or reuse the image (or certain parts of the image)

You’d convert PNG files to DWG when…….you want to transcribe the drawing into operable instructions

An artist designs signboards or sculptures using the software that they know best, such as Adobe Illustrator or Photoshop. This design is then converted to a DWG file, using applications like Scan2CAD.

Then, the design is sent off to a CNC cutting machine vendor, who will manufacture the actual product from the DWG drawing. These machines use the vector files to generate automatic cutting instructions.

CAD programs also allow you to bring your PNG images to life in other ways. You can upload CAD drawings into 3D modelling software, or even create animations from your converted files.

From sketch…

…to CNC

You have two options to convert PNG files to DWG:Convert manually, by tracing the PNG image with a Vector Pen tool

Convert automatically, using a PNG-to-DWG file conversion program

By using the right file conversion software, you’ll save precious hours of your workday

…compared to a one click process!Lots of fiddling about with pens and grab points…

Simply load the file into the conversion program, click a few buttons and voilà! You’ll have to complete some post-processing steps, but it’s still muchfaster than drawing manually.

You could manually draw vectors. This could take hours, or even days! It’s also extremely difficult to get an accurate vector drawing using this approach.

OR

Once the PNG is converted into DWG, you can load the drawing into almost any CAD program

The world is now your oyster, and there are all sorts of CAD tools in your arsenal. You can cut, copy and paste certain elements of an existing drawing. You can edit specific elements of the drawing, such as reshaping Bezier curves,

stretching vectors, converting lines to arcs, and more. CAD software makes it easy to revise and edit drawings.

All sorts of CAD

editing tools in

your arsenal!

From a scanned PNG image to CAD 3D rendering…

An architectural designer can scan a hard copy floorplan. Once it’s converted to DWG, they can share it with an electrical engineer for wiring plans, a structural contractor for structural renovations, a landscape designer, and anyone else who may be involved in the project.

Scanned and saved as PNG

Converted to DWG format

Used to create a 3D rendering

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How to convert: A step-by-step guide (1/2)The entire conversion process takes about ten clicks. Here are the steps to converting a PNG file to DWG using Scan2CAD:

2. Select the conversion settings. In Scan2CAD, there are pre-programmed vectorization settings to help correctly identify the objects in your drawing. For example, the “Architectural” option is designed to detect straight lines and right angles.

1. Load the PNG file that you’d like to convert.

How to convert: A step-by-step guide (2/2)

3. Click “Convert”. Almost immediately, you’ll have a DWG file that you can load into another CAD software. It’s always best to spend a few minutes to thoroughly check your DWG file, examine the outputs and clean it up as necessary.

4. Save the DWG file. Now, you can edit the DWG file with any supported CAD software.

Expert Tips for Conversion (1/2)

Choose the right image quality

1

Reduce the number of colors

2

Simple photos work better for raster-to-vector conversion. For example, a silhouette against a plain background is much easier to convert than a photo-realistic image.

To do this, you can define the color of your canvas for “1-bit color depth”, which supports only two colours. You can also reduce colors using a thresholding tool.

VS

VS

Your goal is to minimize any speckles, noise, hairy lines – if you don’t want it preserved in your vector image, you shouldn’t have it in the raster. Secondly, you need to help the software out by feeding it distinct objects to trace and convert to DWG format.

Here are some markers of poor image quality:

Clean up the image

3

Expert Tips for Conversion (2/2)

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What is PNG?

Image source: http://www.fortuneproducts.com/printing-services/

PNG is a raster image file format. A raster image stores image information in small squares of color called pixels.

PNG supports lossless data compression, which means that it does not lose quality during editing.

1

2

In CAD, PNG is commonly used to capture a screenshot of the CAD drawing whilst edits are being made. This is because PNG images are easily shareable.

3 Did you know?▪ PNG is pronounced “ping”!▪ The acronym stands for “PNG Not GIF”,

to oppose the patenting of GIF

4

Why use PNG files in conversion instead of JPEGs or GIFs?

JPEG GIF PNG

Small file sizeCan display millions of colors, making it great for photographs Lossy file formatBad for logos, line art, and wide areas of flat color

Small file sizeSupports animationSupports fewer colors (hence why it is often used for logos)Although not lossy, it uses dither filters to diffuse colors, altering the image slightly

Lossless compression, so no data lossAllows transparent backgroundsGreat if file size is not an issue (e.g. in raster-to-vector conversion)

Image source: http://makeawebsitehub.com/image-formats-mega-cheat-sheets/

TIFF or Tagged Image File Format, is an image file format for high quality graphics. It is the most popular format amongst graphic artists, the publishing industry, and photographers – anyone who regularly deals with image editing and manipulation.

TIFFs can either be compressed or decompressed using lossless compression, helping you preserve every single detail of your image. Hence, it is the preferred format when scanning photographs and sketches for raster-to-vector conversion.

Of course, greater detail comes at the expense of file size. In addition, TIFF is quite a complex file format, and as a result it is less likely to be supported by more general applications such as web browsers.

However, you should always choose TIFF over PNG

https://en.wikipedia.org/wiki/Tagged_Image_File_Format

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DWG is a vector graphic file format

Here’s a drawing of a house, saved as a DWG file. DWG files store both 2D and 3D data, as well as a database of

dimensional data and metadata

What programs can I use to view and edit DWG files?

▪AutoCAD▪Scan2CAD▪Some versions of Google Sketchup▪DraftSight▪IntelliCAD▪CorelCAD

To view and edit DWG files To view DWG files only

▪ A360 Viewer (online viewer)

▪ DWG TrueViewTM (online viewer)

▪ AutoCAD 360 (mobile and web app)

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▪ Behind the scenes: how are PNG files converted to DWG?


How does the software convert a PNG image to DXF?

Raster-to-vector conversion software basically traces the raster image and reproduces the drawing using vector entities. It also allows you to trace outlines, or retain information pertaining to whether a line is solid or hatched.

It includes algorithms that can:▪ Detect image edges▪ Recognize different types of

lines; angles at which the lines are joined; different shapes; different colors

▪ Recognize text

In order to create the best quality vector image, the software employs a few processing techniques…

▪ “gap jumping” fills in gaps in the scanned raster image, helping create unbroken vectors

▪ corner sharpening to capture right-angles▪ line thickening▪ removal of unwanted spots and specklesTo learn more, check out our article on how vectorization software converts images to DWG.

http://www.scan2cad.com/dxf/convert/how-software-converts-images-to-dxf

The conversion software can also “read” text and “type” it out into editable vector text

If a scanned document contains text, the text is saved as a raster image. Hence, the file conversion software has to regenerate the text in the document using smart OCR (Optical Character Recognition) technology. It’s the same concept as tracing shapes and lines, except that the OCR algorithm detects letters and numbers.

Click here to learn more about OCR and how it works

http://www.scan2cad.com/tips/how-does-ocr-work/

More about extracting text from PNG files

Each program that is capable of OCR will treat text differently. Great ones save whole phrases of text in a single layer – this makes the text easily editable.

However, subpar conversion software may split the string of text into separate characters and jumble the positioning of the text. This makes the text extremely difficult to edit, as you can see in the second and third images on the left.

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Features offered by Scan2CAD

Support for over 40 file formats including DWG, DXF, SVG, PDF, TIFF, and more

Full set of editing tools for both raster and vector images

Smart OCR to recognize and edit text Built-in vector recognition presets to

correctly identify shapes and line types

Raster-to-vector conversion

Raster and vector viewing tools Command line Batch processing Flexible licensing Excellent support 24/7

Other features:

Scan2CAD is the market leading file conversion and editing software

Download your free trial

Scan2CAD includes conversion tools, image editing and cleaning tools, smart OCR, full PDF support, as well as vector recognition and editing. Click on the blue button to learn more about Scan2CAD.

http://www.scan2cad.com/

Text

This guide is brought to you by Scan2CAD, the market leading file conversion and editing software.Get more guides and articles regarding DWG files and conversion tips on our blog:

www.scan2cad.com/blog

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http://www.scan2cad.com/dxf/convert

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Ultimate Guide: PNG-to-DWG File Conversion