This thread is intended to be a collection of tips and tricks for using MeshMixer with the Form 1+. Meshmixer is developed by Ryan Schmidt at Autodesk, and is available as free download from meshmixer.com
Adding Drain Holes to an Object.
There are three ways to add a drain hole to an object in Meshmixer.
- During the ‘Hollow’ operation.
- A Boolean operation.
- The ‘Add Tube’ Tool
Adding Drain Holes during the ‘Hollow’ Operation
‘Hollow’ is found on the edit menu, its a great to turn you solid model in to a Thin & Efficient outer shell
During the Shell Operation, double click on the surface of the model to locate your drain holes. You can drag hole around after adding them, but to remove them you’ll have to use the ‘Remove all Holes’ button and start over. The holes aren’t computed until you click ‘Accept’ and complete the operation.
Using Booleans to create a Drain Hole
A Boolean is a great way to put a drain hole in a model thats already a thin shell, like this vase. We need a drain hole in the base of the model to keep a pressure differential from building up as it prints. Find the Cylinder Primitive from the ‘Meshmix’ Menu.
For this operation to work properly, you have to drag the cylinder from the menu on to the object so it becomes something called a ‘Drop Solid’
Use the menu and widget to manipulate the cylinder. I make my drain holes between 1mm and 1.5mm. The is some wonkeyness to this tool, we can manupulat the lenght to the cylinder, so it may not go all the way through the part. We’ll have to use another tool on it before we can Boolean. Select ‘Create New Object’ from the drop down menu and click ‘Accept’
Use the ‘Transform’ tool from the ‘Edit’ menu to stretch the hight of the cylinder so it so it goes all the way though object. Click accept when you happy with the hole’s placement (In this image I have applied a transparent shader to the object so we can see whats going on.)
Click on first on the Object, then hold select and click on the hole. A context menu will pop up on the left side of the screen giving you options for working with two object. Select ‘Boolean Difference’
Note, If your object doesn’t want to boolean, you may need to add more geometry to it using the ‘Refine’ brush from the ‘Sculpt’ menu. I’ll cover this in more detail in another post
Using the ‘Add Tube’ Tool
‘Add Tube’ is an interesting tool that lets you create a tube runs through the interior of a model from one surface to another. Its an interesting way to add a drain hole to a cavity that is deep inside a larger model. Personally I haven’t found a situation where i need this tool yet, but its really cool so we’ll cover it anyway.
Drag the to red handle to the points on the outer and inner surface where you want the ends of the tube to be. You can play around with the settings to adjust how the tube is routed, but I usually trust the autorouter.
Click Accept to cut the tube through the model. (You’ll notice that the corner of this cube was messed up by the process, This is once again an issue with the geometry being too simple, we’ll talk about how to correct this in another post.)
Unifying a Model’s mesh Into a single solid object
Occasionally Preform’s automated repair tool won’t be able to successfully fix the errors in a model, and you’ll get the dreaded orange pop-up.
This is often caused by complex models made up of multiple overlapping shells with no wall thickness. Thats is a nice way of saying the types of model often found in the game design, architectural visualization, and visual effects worlds.
We can Use Meshmixer to fix this and turn the object in to a single solid model, at the price of some loss of surface complexity.
Loading the model into Meshmixer, we can see some of the errors highlighted in red and blue.
The function we need is called ‘Make Solid’, its found ‘Edit’ menu. Make Solid is will create a new model by wrapping the original in a mesh then shrink wrapping it to the surface.
When you first activate ‘Make Solid’ Meshmixer will create a rough approximation of the outer shell.
The mesh can be made much more accurate by tweaking the the settings. Change the mode in the drop down box from Fast to Accurate, and set the ‘Solid Accuracy’ and ‘Mesh Density’ at around 450. Click ‘Update’ for meshmixer to re-compute the shell. Click ‘Accept’ when your happy with the results.
Before exporting the repaired file, we’ll need to delete the original model. A window titled ‘Object Broswer’ should have appeared on your screen. It shows two versions of your model, the original and the repaired version. The repaired version will have (solid) added to the end of its name. Select the original model and Delete it by clicking the trash can.
All thats left is to export the model as an STL and load it into Preform. The automatic repair should run successfully
Model used in this post:
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