Troubleshooting Mesh Issues

0.0 Troubleshooting Meshes

0.1 Checking a Meshes

Checking for whether your mesh is 'good' is an imperative step when preparing your file for 3D printing. For instructions on how to check your mesh click please see our Checking Meshes Guide.

0.2 Checking Tolerances

Check your tolerances are set correctly and suitable for 3D printing. In most cases it is safe to use a 0.01mm.

Command : Units
Figure 0.2 - Check your tolerance is set correctly in your rhino file

0.3 Checking Polygon Count

A model with 100,000,00 polygons come often be too difficult to print and hard to manage. If this is the case reducing your mesh can make printing and working with the file much easier. Reducing your mesh can result in a lower resolution so a judgement call will need to be made to on how much resolution is acceptable to lose.

Command: Reduce Mesh

1.0 Repairing Meshes in Rhino

1.1 Displaying Backfaces, Naked Edges and Non-manifold Edges

being able to see the problematic areas on models can be useful when trying to gauge how much repairing/repairing a model. Change the following settings in Rhino display modes in order to display backfaces, naked and nonmanifold edges.

  1. Ensure your display mode is set to shaded by clicking on the drop-down menu on the viewport name. There should be a small black dot on the left-hand side next to the display mode that is currently in use. For troubleshooting we recommend that you are in 'Shaded mode'.

  2. From the drop-down menu select 'Display Options'

    Backfaces

  3. In the shaded options click on the drop-down menu for 'Backface settings' and select 'Single Color for all backfaces'

  4. Click on 'Single backface color' the swatch box (The default is usually white) from the color list select orange.

    Naked Edges

  5. Within the Shaded options expand the 'Object' options and then click on 'Meshes'.

  6. Within the Naked edge settings click the drop-down menu for 'Edge color usage' to 'Use single color for all naked edges'.

  7. Change the 'Edge color' by clicking of the swatch and selecting red from the color list.

  8. Change the 'Edge thickness (pixels):' to 2.

    NB : If you are working with surfaces and would like to display these options you will need to change the settings within your 'Surface' settings as well.

    Non-manifold Edges

  9. Within the Non-manifold settings click the drop-down menu for 'Edge color usage' to 'Use single color for all naked edges'.

  10. Change the 'Edge color' by clicking of the swatch and selecting purple from the color list.

  11. Change the 'Edge thickness (pixels):' to 2.

    NB : If you are working with surfaces and would like to display these options you will need to change the settings within your 'Surface' settings as well.

1.2 Repairing Backfaces

All surfaces and meshes in 3D Modeling programs have a positive and negative side. In order for a model to be print ready, all positive faces need to be on the outside of a model. Now that your display settings have been adjusted, negative face will be highlighted as an orange surface.

If you have a single face that needs to be corrected, isolate the face by exploding it from any correct facing faces and then flipping the face. Be sure to re-join your faces once flipped as you model may now have naked edges.

If there are many faces that need to be flipped the 'UnifyMeshNormals' command can be used.

Commands: Explode, Flip, Join, UnifyMeshNormals

1.3 Repairing Naked Edges

Naked edges are a result of holes or disconnected edges within a water-tight 3D Model. Now that your display settings have been adjusted, naked edges will be highlighted as a red edge.

To correct any naked edges that may be a result of disconnected edges select all faces and use the 'Join' command.

If after joining all faces and your model is still displaying naked edges it is possible that this may be because of holes within your model. If the holes are visible you can use the 'FillMeshHole' or the 'FillMeshHoles" if there are many.

Sometimes holes can be very small and will require a very zoomed in view, use the ZoomNaked command.

Commands: Join, FillMeshHole, FillMeshHoles, ZoomNaked

1.3 Repairing Non-Manifold Edges

Non-manifold edges are Edges of polysurfaces or meshes that have more than two faces joined to a single edge are non-manifold. Now that your display settings have been adjusted, naked edges will be highlighted as a purple edge.

To repair non-manifold edges use the 'ExtractNonManifoldEdges' to separates from the parent mesh non-manifold faces.

1.4 Repairing Duplicate Faces

Duplicate faces are extra unnecessary copies of faces these faces may be the cause of naked edges will produce complications when printing. To delete duplicate face use the 'SelDup' command and then press the 'delete' key.

Commands: SelDup, Delete

2.0 Mesh Repair Services and Software

For bad meshes that are proving to be difficult to troubleshoot the following services and software may be useful in repairing naked edges and non-manifold edges. Once the mesh has been repaired the file should still be checked as there still may be a possibility that the 'repaired mesh' is still bad.

2.1 NetFabb

Netfabb is a free online service that allows for repair of .stl .obj .3mf and .vrml files that are a maximum of 100MB. This service allows you to upload a file, it will then process a repaired file that can be downloaded. For this service you will be required to log into an Autodesk account.

2.2 NetFabb Alternatives

2.2.1 Microsoft's Tools3D

Microsoft's Tools3D is a free online that allows for repair, reduction and file conversion of 3D Files that are a maximum of 100MB. Tool 3D will allow you to work with .stl .obj's and .vrml file types. To use this service you will be required to log in to a Microsoft account.

2.2.2 Meshmixer

Meshmixer is state-of-the-art software for working with triangle meshes. It can be helpful when cleaning up 3D models prior to 3D printing. This software is available to use on computers in the MSD student computer labs. For computer lab locations click here.

2.2.3 Netfab (Paid Version)

For more extensive repairs the paid version of Netfabb can be used.

For a Meshmixer Boolean and clean up video tutorial click here.