3D printing with Meshmixer
*All images credited by Paul Hatton and models supplied by Artec3D*
3D printing has come on leaps and bounds in the last decade. It is becoming cheaper and cheaper with every passing year and the day that 3D printers made their way into people’s homes was a game changer. Setting up your 3D model correctly is incredibly important and for a free piece of software Meshmixer is a perfect tool for this purpose.
Fill in any holes
Start by selecting the polygons that surround your unwanted hole. Up will pop a new menu which will include a sub-menu called Edit. If you go in there you’ll find the Erase & Fill tool. Click this and you’ll see your hole magically filled. You can also fill all large holes by deselecting any polygons and going to Edit > Make solid. Adjusting the Solid Accuracy parameter will determine how accurately gaps are detected. Use the slider to get the results you want.
The automated tools for filling holes are excellent
Hollow out your model
Printing 3D models is not the cheapest thing out there so if you think you can save some money hollowing out your object then this is how you do it. Click on Edit followed by Hollow. Notice your object is now see-through with the hollowed-out volume in black. Adjust the Offset to set the thickness of your model. Use the Solid Accuracy to determine the accuracy of the hollowed-out areas and the Mesh Density parameter to adjust the smoothness. Don’t forget to click Accept to confirm your changes.
Hollowing out your model will save you money on materials
Create custom escape holes
With a hollow model you’ll need to make sure you allow for any excess material to escape from the inside of your model. This is done by inserting escape holes into your model. You can do this easily in Meshmixer while performing the previous step of hollowing out your model. If you’re printing something relatively small then a couple of holes will be sufficient. You can see this using the Holes Per Hollow parameter. Before clicking on Generate Holes you’ll want to set the Hole Radius. With the holes created simply reposition them by dragging the red dots. For specific requirements regarding these holes it’s best to speak to the company doing your printing.
Escape holes allow for excess material to escape
Get the thickness right
Run the thickness analysis by going to Analysis followed by Thickness. After the analysis is complete simply enter the Minimum Thickness as per the requirements of your printing supplier. With that done you’ll see the areas of your model which are too thin. Clicking on the blue spots will select the areas. To sort thin areas use the Make Solid tool and by adjusting the accuracy and density parameters you can thicken the problem parts.
Set your model thickness to be in line with your printer’s requirements
Get your model on the ground plane
Transform your object so that it’s in the right place in your 3D space. Do this by using the menu on the left-hand side and selecting Edit followed by Transform. Up will pop the properties panel to enable you to specify things like translation, rotation and scaling. Alternatively, you could use the transform widget in the interface to transform your object. Accept the transform. You may also want to use the Edit > Align tool.
Move your model onto the ground plane
Smoothing your model
Depending on how you created your model you might need to carry out some smoothing. This will be particularly true if your model was created through a 3D scanning process. You might find yourself with jagged and ridged geometry that is undesired. To smooth your model you can make use of Meshmixer’s sculpting tools. Simply go to Sculpt > Brushes > Brushes > Robust Smooth.
Smooth your model with the sculpting tools
Create support structures
If you have any overhangs that are not able to support themselves then you’ll need to create your own custom support structures. Meshmixer lets you do this. Begin by going to Analysis followed by Overhangs. Ideally choose the Preset for your 3D printer. Open up the Support Generator. If you’re overhangs are quite high off the ground plane you’ll want to select Allow Top Connections in the Advanced Support section. This will ensure supports are generated off the model itself rather than from the ground plane. Once you’re happy with your settings click Generate Supports. You can remove any supports by clicking Ctrl and your left-mouse-button at the same time. To merge your supports into your main object simply click Convert To Solid.
Support structures will keep your model stable
You will hopefully have a mesh that is ready for 3D printing but there are a ton of other tools that will help you further improve your model and in turn your 3D print. The final tool that I want to point you in the direction of will help repair any final issues with your mesh. You can find it in Analysis > Inspector. It will inspect your model and suggest any repairs. Simply select Auto Repair All to action them.
Auto repairing any faults in the model will give you that extra piece of mind before going to print
Export & print
Having followed all the steps so far, you’re now ready to export your model. Do this by going to Export. Choose the file type you want. Most of the time you’ll export using an STL format but there are others available. It’s as simple as that! To sort out the slicing of your object you can either open the exported file in a separate slicing program or if you own a supported 3D printer you can send your model directly to it by hitting Print on the left-hand side menu.
Export your model into your desired format
Meshmixer has an incredibly diverse set of tools. We’ve only scratched the surface here but I would recommend that anyone interested in 3D printing experiments with all the tools that Meshmixer offers. Meshmixer has extensive documentation and is relatively easy to follow. There is also a search feature within the documentation which is especially useful. Happy 3D printing!