Meshmixer is a free Autodesk program, compatible with both Windows and MacOS, that’s aimed at working with 3D meshes. As of September 2021, Autodesk stated that they will no longer develop or support the program – but it’s still usable. However, if you need more backing, many of the features can still be found in the capable and powerful Fusion 360, and more mesh features have been promised.
In contrast to the customarily solid CAD models, polygon mesh 3D models are represented by faces, edges, and vertices that, together, define the spatial shape of the object. Such mesh representations may already be familiar to 3D printing enthusiasts: The STL format is a triangular mesh representation, and 3D scans also use polygonal mesh forms to represent objects.
These particular representations can’t be easily worked on in traditional CAD software, and this is when Meshmixer comes in handy. It has tools and features that allow for more or less the same editing capabilities as CAD programs. Further, Meshmixer was developed specifically for 3D printing applications.
With beginners in mind, this article will walk through the initial steps in editing and correcting a mesh file, taking you all the way to making the final adjustments for 3D printing. This tutorial will use the “Stanford Bunny,” a Meshmixer standard model from a 3D scan of a ceramic figurine, as our example.
Let’s get started!
In this section, we’ll go over the first steps for using this great tool. These steps include importing an external model, learning the UI basics, and viewing modes.
But first things first, download and install Autodesk Meshmixer if you haven’t done so yet.
Once you’ve properly installed and opened Meshmixer, you’ll be greeted by the opening screen with some starting action buttons.
The Import button will bring into Meshmixer an external mesh file of your choice. All of the most common mesh formats are supported (STL, OBJ, PLY, AMF, 3MF, OFF, and MIX).
You can also simply drag-and-drop the mesh files into the edit space and either replace the current object or append to the model.
By default, Meshmixer uses a somewhat different XYZ orientation than what we’re used to with 3D printers: The axis responsible for the model height is the Y while the ground plane is the XZ. (In the 3D printing world, the Z-axis is usually the build direction.)
Since most Meshmixer applications involve 3D printing at some point, it would be nice to have the same XYZ orientation as 3D slicers. While we can’t change Meshmixer’s environment orientation, we can change the model’s default orientation during file export. This will ensure that the model, once imported into the 3D slicing software, has the same orientation as the slicer.
Be it CAD software or 3D printing slicers, every 3D environment offers a set of functions to adjust the user’s “camera” view. For Meshmixer, the options include the following:
You can also access all these tools by holding down the space bar. A menu appears, and the desired tool can be selected from the camera options: Click the desired tool and hold down with the left mouse button to select it.
If you end up losing your model in the vast 3D environment, which happens from time to time, select “Recenter View” from the View menu to focus on the center of the coordinate system once again.
There are two ways you can position and scale the model in Meshmixer: the Transform tool panel or the 3D transform widget.
Rather than entering values in the Transform tool panel, you can use the mouse to click and drag on the colored icons via the 3D transform widget that appears on the model.
Checking “Enable Snapping” at the bottom of the Transform tool panel allows you to control these transformations in incremental “Snap Steps”, which can be pre-defined by entering a value based on whatever level of accuracy you need.
Meshmixer offers different object view modes, called Shaders, that control the appearance of the 3D models.
The default and Overhang Shaders are particularly useful for 3D printing.
In Meshmixer, the 3D environment can be customized to match the build platform of specific 3D printers. This is especially useful when handling multiple objects that will be printed in one job.
You can see the printer bed in the 3D environment by checking “Show Printer Bed” in the View menu. To disable the display of the print space, simply uncheck this option in the View menu.
Setting up a customized print space can be done in two ways, either by selecting a pre-defined printer in Meshmixer or adding a new one manually.
You can browse through the printer selection widget to check if your 3D printer is pre-programmed in Meshmixer.
The 3D environment will be updated, and the build plate size will be adjusted accordingly.
In case your 3D printer isn’t on the list, you can manually input the print volume dimensions.
Now that we’re acquainted with Meshmixer’s basics, let’s go over the main tools and features for working on the model and getting it ready for 3D printing.
One of the program’s most popular capabilities is that it can analyze and correct defective meshes, but also noteworthy is the ability to add escape holes and create customized tree supports.
3D models from websites such as Thingiverse and MyMiniFactory are usually created by the user community and sometimes come with defects. It’s also very common to find defects in 3D scanned data. These mesh issues must be dealt with prior to even thinking about 3D printing.
Meshmixer offers both automated and manual tools for correcting mesh tears and holes. Let’s start by looking at the automated way.
One simple way to locate and correct defects is to use the Inspector tool.
Press the Analysis button on the left panel and select the Inspector tool from the menu. The analysis will run automatically on the selected model(s). Once computed, any mesh issues will be highlighted in different colors pointing out potential holes and gaps.
The colors symbolize the overall severity of the issue:
Meshmixer usually does a good job fixing all found issues regardless of the severity. Click on a single ball sign to fix errors individually, or click on “Auto Repair All” in the Inspector tool panel to do it automatically.
It’s always a good idea to check the repaired areas after the process and even to run the Inspector tool a second time.
Some models, especially those obtained via 3D scanning, might not display a good flat surface. Good bed adhesion is critical for successful 3D printing, and it’s fairly simple to accomplish in Meshmixer.
The Plane Cut is a fast tool that can be used to create a smooth and stable surface to print on.
Sometimes it can be a good idea to hollow 3D models in order to save time and material when 3D printing. This is a popular strategy with resin printing since the feedstock material can be quite expensive. For these processes, the unused liquid resin will remain inside the model unless we create escape holes.
Folks at Autodesk are aware of this, and Meshmixer has a special tool designed for doing both things:
Meshmixer offers great tools for creating support structures for 3D printing. While most (if not all) 3D slicers offer the same capabilities, Meshmixer allows the creation of a different kind of structure: tree supports. These are not offered in all slicers, although you’ll find them in Cura and PrusaSlicer. In contrast to standard lattice structures, tree supports are desirable because they require less time to print and are an efficient way to use the materials.
The automatic support feature will create support structures for the areas highlighted by the Overhang Shader we mentioned earlier, and this can be a very good starting point for a more customized approach. This very rich feature has an in-depth review and tutorial of its own.
With the model duly edited and ready for materialization, it’s time for the final checks that should make your life much easier during slicing and printing.
It might be a good idea to double-check whether the model is flat on the build table after all the transformations we did. Meshmixer’s Stability tool will calculate the total surface area, the volume of the object, and will also outline in red the contact area between the model and the ground plane.
Furthermore, Meshmixer will tell you whether this current position might tip the standing object. A red dot in the middle of your object will indicate an unstable position, meaning that the model needs to be repositioned in the build table. A green dot indicates a stable position.
To do the stability check, press the Analysis button on the left side panel and select “Stability” from the menu.
If your model’s unstable, there’s a great trick to place the model perfectly onto the ground plane without spending too much time with the Transform tools:
Check the placement of your model by using the Stability tool again. It should now be placed perfectly aligned with the ground plane.
In case the model has been hollowed out as shown in step #9, you might want to ensure that the object shell has an adequate uniform thickness for 3D printing. Although we’ve set the Offset Distance to define the wall thickness of the final model, in reality, that might not be consolidated. To check that, we’ll use the Thickness tool.
In our example, the bunny has been hollowed with an Offset Distance of 2 mm. The Thickness analysis, however, shows in red the areas where the thickness measured less than 1.5 mm.
Depending on each model’s requirements, it might be a good idea to hollow the object with a thicker Offset Distance to ensure enough thickness across all areas of the model.
Now the 3D model should be optimized for 3D printing. You can export the model by clicking the Export icon on the left panel. You have the option of several supported file formats, including the popular STL. Before you print the model, however, it still requires traditional slicing in any other program of your choice.
With that, you’ve completed your very first steps in Meshmixer. Congratulations!
In addition to the tools and features we reviewed in this tutorial, this powerful software offers many other capabilities, such as 3D modeling from scratch and manual editing tools.
License: The text of "Meshmixer Tutorial for Beginners" by All3DP is licensed under a Creative Commons Attribution 4.0 International License.