Draw 3D Inkscape Extension

Draw 3D is an open-source extension for Inkscape 0.9 that lets you generate GCODE which will enable your 3D printer to hold a pen and draw.

The original inspiration came from this video by Teaching Tech where he showed the method to generate GCODE using Jtech Laser Inkscape extension. I have modified this extension to make it better and easy to use. I have made the changes in the extension so it can do only one job i.e. generate gcode to let your 3D printer draw on a piece of paper. The hardware setup in this post is demonstrated using an Ender 3 pro but you can use the same idea on pretty much any FDM 3D printer.

Extension Installation

The first step is to download Inkscape 0.92.4 from this link and install it. Note the installation folder while installing. It is important to note use the latest version of Inkscape because the extension is not compatible with that.

After that go to the github link of the extension and download the code as zip file.

Extract the zip file and copy the two files umer_plotter.inx and umer_plotter.py from the extracted folder.

Go to the {Installation Folder}/share/extensions and move the umer_plotter.inx and umer_plotter.py files to this folder. Remember you noted the installation folder in the first step.

The extension installation on windows is now complete.

Pen Attachment

The next step is to attach a pen to the head of your 3D printer. It is better to use a system that can sprint up and down a little bit. I have this small hack that you can do with a ballpoint to achieve that. Put some electrical tape near the middle of the pen’s refill and place the spring over it. Now, when you put it back in the pen, the spring will be pushing the nib down and the nib will be able to sprint a little bit into the pen if some force is exerted on it.

You can mount this pen on a fixed pen holder like this one for my Ender 3 pro

Or you can use a sliding mechanism with a fixed pen.

Here are links to printable pen holders for Ender 3/3pro, CR10 or similar printers designed by me:

• https://www.thingiverse.com/thing:4574948
• https://www.thingiverse.com/thing:4721453

You can find many other designs on Thingiverse. Just print a holder and mount a pen on your printer’s head.

Take Measurements

We need to measure a few things because the extension will require these to generate the code for your printer.

First, measure the x and y dimensions of your printer. You can also google the size of the build plate for your printer.

Mount the pen. Attach paper on your bed with binder clips. Then use the move axis menu on your LCD or any other tool such as octoprint or pronterface, move the pen’s nib to the bottom left corner of the paper where you want the drawing to start. Make sure to leave some clearance for the binder clips.

Now, just note down the position of your X, Y and Z axis.

Also, get an estimate of how much you need to raise the pen so that it stops touching the paper. In my case, raising it by 5mm is more than enough.

Plugin Settings

Open Inkscape, go to Extensions > Generate Plotter Gcode > Draw 3D GCODE Generator

In the next window, you can input the measurements that you have taken in the previous step.

An explanation of all the options is given as follows:

Offsets

• X Offset is the position of the x axis when the pen is just at the bottom left corner of the drawing area
• Y Offset is the position of the y axis when the pen is just at the bottom left corner of the drawing area
• Z Offset is the position of the z axis when the pen is just touching the bottom left corner of the drawing area

Bed Dimensions

• Bed size X axis is the total size of the bed in x axis
• Bed size Y axis is the total size of the bed in y axis

Plotting Information

• Pen Lift Height is the height in z to lift the pen so that it stops drawing
• Drawing Speed is the speed with which the pen moves when it is pushed against the paper
• Travel Speed is the speed with which the pen moves when it is lifted.
• Passes is the number of times it is going to draw the complete drawing. You can increase this value from 1 if the pen does not draw well in one pass.

Output

• Specify the path of the output folder in Output Directory
• Specify the name of the output file in Output Filename option
• Checking the Add numeric suffix to filename will add a 3 digit number at the end of the file so that it is not overwritten by the new one.

Generating GCODE

First, set the drawing area size in Inkscape. To do that, go to File > Document Properties

Calculate the x and y drawing size as:

X Drawing Size = Bed Size X axis – X offset

Y Drawing Size = Bed Size Y axis – Y offset

Input the X drawing size in width and the Y drawing size in height. Make sure the units are mm.

We need to import an image into Inkscape and convert it to vector. You can use the following image to get started.

Go to File > Import and import the image into Inkscape

Adjust its size. Then go to Path > Trace Bitmap

Check the Live Preview button and click OK. Other options remain default.

Now, open the extension, specify the output directory and filename and hit apply.

It can take a few seconds to generate the gcode. Once it is generated, you can run it on your printer that has the pen attached.

There are also some hacks that can be done using custom start and end gcodes with the extension because I have added support for custom start and end gcodes in the extension. Place the start gcode in header_plotter_plugin.txt file and the end gcode in footer_plotter_plugin.txt file. The files need to be in the output directory.