What is Cura?
Cura is a software program that renders 3D models created in a 3D modeling program into printable files for any 3D printer. It slices the 3D object into layered information that tells the hot end extruder (print head nozzle) on the 3D printer where to lay melted thermoplastics. There are two types of thermoplastics, PLA and ABS that are commonly used. Most 3D printers print one layer at a time and stacks those layers on top of each other like ultra-thin Legos blocks. Cura is made by a 3D printer company called Ultimaker, but it’s compatible with most 3D printers. You can download the software for free here: https://ultimaker.com/en/products/cura-software. This tutorial assumes you already know the basics of Cura. If you are new to Cura, please reference the two excellent beginner videos at the end of this article.
You will need Cura, a computer, a 3D printer, and PLA or ABS filament. This article and tutorial was made possible by a company named New Matter who generously donated 3D printers to Arcadia Unified for educational purposes. Their Mod-T is affordable, reliable, and user friendly and I highly recommend them. Their website is https://newmatter.com/.
Making a 3D Relief from a 2D Image
Do a Google search for a 2D image that you want to change into a 3D relief and download it. Make sure the image is under a noncommercial reuse license for your protection. If it’s in color you will need to change the image into black and white because Cura will raise the darker areas and lower the lighter areas. The darker it is, the higher it will be. You can also reverse it in the setting.
Step 1: Open up Cura.
Step 2: Load your 2D black and white image or drawing into Cura. For this example, I’m going to import a 2D map of California.
Step 3: Once you’ve imported your black and white image, a customizable pop-up box will appear. The ‘height’ value defines how tall the darkest areas will rise above the plain. You can play with it to see what suits you, but for this example, I’m going to change it to 5mm. The ‘base’ value defines how thick or tall your 3D object’s base or foundation is. By default, Cura creates a base for your 3D object to sit securely. I’m leaving it at 1mm height for now. The ‘width’ and ‘depth’ values allows you to shrink or expand the size of the object. You can play with it if you want a smaller or a larger 3D object.
Step 4: You have the option of choosing “Darker is higher” or “Lighter is higher”. Due to the nature of the image I imported, I’m going to select “Darker is higher” because the darker areas represent mountains. Feel free to play around with this setting to see what suits you.
Step 5: The last box in the setting gives your three options: ‘No smoothing’, ‘Light smoothing’, and ‘Heavy smoothing’. This setting determines how much smoothing is applied to your object. If there are rough edges like jagged mountains, you might want to apply some smoothing. Feel free to experiment to see what suits you, but for this example, I’m going to select ‘Light smoothing’ to eliminate sharp spiky mountains and smooth it out.
Step 6: Once you’re satisfied with the values for your setting, click ‘OK’.
Step 7: Your 2D image will now load into the Cura work space. As you can see, the darker areas are higher and the lighter areas are lower.
Notice that California is sitting on a rectangular base or foundation. If you are happy with the current results, you can export it as a gcode file and send it on a 3D printer for printing. Personally, I prefer getting rid of the base because I want my final 3D object to be in the shape of California without that ugly rectangular base. Trust me, it will look much prettier.
Step 9: Find the menu bar on the top left hand side of the Cura window. Currently, it’s on the ‘basic’ tab by default. You need to click the ‘Advanced’ tab on the menu.
Step 10: On the column to the left, find the setting ‘Cut off the object bottom (mm)’. This setting does exactly what it says. Entering a positive value will tell Cura how much base to cut away. The default value is zero. Change the value until the base/foundation moves below the blue checkered plain. The base will turn from yellow to greenish. Yellow indicates that the object is within the work space. Greenish indicates it is outside of the work space and therefore will not be included in the final print. For this example, I selected a value of 1.2mm. This will drop the 3D object 1.2mm below the plain thereby eliminating the base/foundation from the final design. Feel free to experiment with this value to suit your needs. If you are happy with your result, you can skip to Step 13 and export it as a gcode file, but I suggest continuing to the next step to double check your design.
Notice that the base is now below the blue checkered plain. Everything above the plain will be printed. Everything below the plain will not be ignored.
Step 11: You really should double check your 3D object to make sure your base/foundation is completely gone before exporting it as a gcode file. Find the hour glass icon on the top right hand side of the window. It is labeled ‘View Mode’. Clicking it will display a drop down menu of smaller icons. Select ‘Layers’. This will change the viewing mode of your 3D object and display each single layer at a time. This is what your 3D printer sees as it prints each layer.
To scroll through the layers, a scroll bar will appear on the right hand side. Move the slider up and down to review the layers of your 3D object. As you can see, the rectangular base/foundation is completely gone from our design.
Feel free to rotate your 3D object to look underneath it. Right mouse click to rotate object. Here is the bottom view of California. Notice that the rectangular base/foundation is gone.
Move the slider on the scroll bar on the right hand side all the way down until the value is 1. This how the first layer of your 3D object will look like. It’s a flat plain shaped like California. This is what I want.
As you slide the slider up, layers progressively stacked on top of each other as the object magically grows from the ground up.
This is the bottom view of California with the slider moved all the way to the top of the scroll bar.
Step 12: You can exist ‘Layers’ view mode by clicking the ‘Normal’ icon located on the top right hand side of the window to return to normal viewing. Your object is ready to be exported as a gcode file.
Step 13: Find the menu on the top left hand side of the window and click ‘File’. Under the drop down menu, click ‘Save Gcode’ or alternatively, you can press CTRL+G on the keyboard. A pop-up window will appear. This action will export your 3D object to a file format that is friendly to 3D printers.
Step 14: Give a name to your gcode file. I called mine, ‘California’. Click ‘save’. Congratulations, you have converted a 2D image into a 3D object that can be printed on any 3D printer.
The Final Product
Now that you know how to convert a 2D image into a 3D object, here are some additional ideas on what you can do with this powerful Cura tool. I took colored photos of my students, converted them into black and white and printed 3D reliefs of them to show off during Open House. For social studies, students learned about California Missions and produced 3D images of Father Serra from a 2D picture that was found on the internet. Lastly for art, we converted Vincent Van Gogh’s famous Starry Night painting into a 3D relief. I suggest having students draw thick bold swirling lines using a black sharpie with a wide tip on white paper while keeping white space between the lines. The white and black will create hills and valleys and give your 3D object texture. Then, take a photo of the drawing using a smart phone or camera and import the image into Cura. Parents will be delighted to see their child’s art printed on a 3D printer!
Beginner’s Tutorial on using Cura
Here are two YouTube videos for beginners learning how to use Cura.