Learn How to Use Blender for 3D Printing
What is Blender?
Blender is a complete 3D graphics creation tool that is free and open source. Some features of Blender include 3D modeling, UV unwrapping, sculpting, animating, texturing, raster graphics editing, rigging and scripting, fluid simulation, smoke simulation, video editing, and compositing. You can create everything from animated films to 3D video games with Blender.
For those who need a bit more functionality, you can also expand Blender with Python scripting and add-ons. Blender is also cross-platform, so you can download and install Blender on Windows, Mac OSX, or Linux.
In this article, we will be looking specifically at how you can use Blender for 3D printing. The same type of models used for video games and animated films can export to print real-life objects.
Last Updated August 2021
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To get started using Blender to create 3D models for printing, download Blender for free at the official Blender website and install it. There, you will find installation files whether you have a Windows, Linux, or Apple computer. Once you have downloaded Blender and installed it, start it up. Blender will first ask you how you want to configure your installation. You will have to select the color scheme, language, and other details before proceeding. Once that is done, you should see a default scene with a cube, camera, and light in it.
Tips for 3D printing with Blender
Configure your model units correctly
The model you are creating is for the actual world, so you need to use real-world units using a scale that fits the size of the object you want to print. The current version of Blender uses the metric system, with the default length unit being meters. So this is the first setting you need to check in the model because you could end up with a model that is bigger than you expected. You can do this by going to the Units panel in the Scene Settings. In the default configuration of Blender, you can find this in the lower right panel, as shown in the image below.
Set the Length to millimeters or inches if you prefer, so you have a model that will fit your 3D printer. Millimeters is the most common unit used by 3D printers. If you plan on using Blender for 3D printing, you might want to save your settings as default by going to File -> Defaults -> Save Startup File. That way, you won’t have to set this every time.
Remove the camera and the light
Blender may add a camera and light to a new scene. You don’t need these for 3D printing so that you can remove them from your scene. In the Scene Collection menu, also known as the Outliner, find Camera and Light, right-click on them, and choose Delete. In the default Blender layout, this menu is in the top right.
If you want to, you can just hide the camera because you may want to do a test render to get an example of what your resulting object will look like during the modeling process. You will need the camera to do that.
Create a boundary guide
If you know the dimensions of the 3D printer you are using, then you know the limitations of the model you are building. You can use the default cube that Blender puts in the default scene as a guide for the size limitation of your model. Then build your model inside of it. So select the cube in Object View and click N on the keyboard. This will bring up the Properties panel. Inside the panel, you will see a Dimensions section, as shown in the picture below. Set the X, Y, and Z values to the limitations of the 3D printer you will be using.
Now that you have done that, you have another step before you can start building your 3D model inside of it. Choose the Object Properties menu in the bottom right panel in the default Blender layout. Open the Viewport Display section and find the Display As dropdown. By default, this will be Solid. Set it to Wire, as shown in the image below.
Now the cube will be a wireframe you can see through.
For added convenience, you can do one last step so you don’t accidentally select your guide instead of your model when you go to export it. Find your guide cube in the Scene Collection panel in the top right of the scene, which should still be named Cube. Name it something that will stand out and tell you it is your guide, like GUIDE.
Check your mesh for holes
In order to print your model, it has to be a solid mesh. A mesh consists of:
• Vertices: the points that make up the structure of your mesh
• Edges: the lines between the vertices
• Faces: surfaces created by a minimum of three edges
To turn your model into something you can print, you only have to do some editing. So switch to Edit Mode by selecting your model and switching the mode from Object Mode to Edit Mode. In the default Blender layout, you will find this at the top left of your scene. There you will also find the tools for modifying your vertices, edges, and faces.
You must make sure that your mesh has no holes. This can cause errors when you try to use it for 3D printing. In Edit Mode, you can fix holes in your mesh by selecting the edges surrounding a hole and pressing F on the keyboard. This action will create a face that covers the hole.
There is even an easier way to fill holes in your model. In Edit Mode, go to the Select menu in the top left of your scene and choose Select Similar and then Non-Manifold. This will automatically find all the holes in your mesh and select all the edges surrounding them. Then just click the F key to fill all the holes at once with faces.
For bigger holes, select the edges manually. Use the Grid Fill option so that the holes get closed, but the vertices are maintained, and your model doesn’t change shape.
Add an escape hole
Before you remove all the holes in your model, you might want to leave one. Making your 3D models hollow saves on printing material. The steps to making your model hollow include using the solidify modifier to give the walls of your model some thickness, which we will discuss the solidify modifier in the section below. After that, some 3D model creators like leaving a small hole at the bottom of their model to allow excess material to escape during the printing process.
Using Blender modifiers on 3D printing models
Blender has a lot of built-in tools called modifiers that can make the process of preparing a model for 3D printing a lot simpler. They run automatic operations on your model that would take too much time to do manually. These tools can be accessed in the Properties bar when you have Blender in Object mode. You will find this under the wrench icon in the lower right panel of Blender
Here are a few modifiers you might want to use on the 3D models you will use for printing.
Use the remesh modifier to shape up your model
If your model has too many small faces or sharp edges, it could be brittle when it prints. You can change the mesh with the remesh modifier. The remiss modifier will simplify your mesh globally without modifying the geometry of your model. Sometimes when you import a model not designed for 3D printing or Blender, it will have too many faces.
Use the decimate modifier to simplify your model
The decimate modifier does something similar to the remesh modifier. The remesh modifier will try to preserve the vertices of your original model. The decimate modifier will remove vertices and edges in an attempt to simplify the model. There is a fine line between simplifying a complex model and removing too much detail. It all depends on how you configure the modifier’s settings.
Use the solidify modifier to give your model strength
If your model is going to exist in the real world, it is going to need to be thick enough to stand up to wear and tear. Your model should be at least 1 mm thick to withstand the printing process and afterward. Using the solidify modifier, you can apply the thickness you choose to the surface of your model.
Use the boolean modifier to join objects
You can use the boolean modifier to turn two objects into one or remove one object from another. It has three operations:
• Difference: This will cut the shape of one object out of another object.
• Union: This operation will take both objects and join them together to make one object.
• Intersect: This operation will only keep the volume occupied by two objects.
Using these tools, you can build a complex model up out of simpler objects.
Now that you have modified your model for 3D printing, it is time to check it for any errors and export it. First, you will want to activate a Blender add-on that will make this process easier and more trouble-free.
Install the 3D print toolbox add-on
The 3D print toolbox is an add-on you can install in Blender that will allow you to analyze your mesh. This will help you find issues in your model that may cause it to fail when printing. But it is not installed by default with Blender. To install it, go to the Edit menu in the top navigation and choose Preferences. On that menu, select Add-ons on the left. Use the search there and search for “print.” When you see the 3D Print Toolbox, check the box by its name.
Close Preferences, and now you should see an extra tab on the Toolbox where we adjusted the dimensions of the guide box we created. You can see it in the image below.
Analyzing and exporting
The last step before you export your model should be to analyze it for anything that could cause printing to fail, as well as removing any extra faces, edges, and vertices that you won’t need on the final model.
One way to clean up your model is to switch to Edit Mode, select the model by pressing A on the keyboard, open the Specials menu by clicking W, and choosing Remove Doubles. This is a quick way to remove any unnecessary polygons in your model.
If you installed the 3D print toolbox, then you will have many more tools to make sure your model is ready for the slicer. Clicking Check All will run all the checks on your model, showing where it encounters any errors. It will give you a count of the following issues:
• Non-manifold edges (or holes)
• Bad contiguous edges
• Intersect faces
• Zero edges
• Zero faces
• Non-flat faces
• Thin faces
• Sharp edges
• Overhang faces
You can fix a lot of these issues with the modifiers we covered above. Once you finish correcting any problems the 3D print toolbox finds with your model, then it is time to export it in a format that slicing software can use. You can do this in the 3D print toolbox menu in the Export section, where it will automatically select STL file format. Or you can export your model the regular way by going to the File menu, choosing Export, and then the STL file format.
Blender is an excellent tool for 3D work because it is open-source, free, and can do just about anything in 3D that you would want. But because it is a complete 3D suite, it is not specifically set up for 3D printing projects. You’ll have to configure Blender and modify your model to get the results you want. The tips above should make it a little easier and worth the effort of learning Blender to use with your 3D printing projects.
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