Avoid mistakes that occur when designing 3D files for 3D printing on Rhino

At Sculpteo we have developed some great automatic mesh repairing algorithms that you can easily access online through the upload environment. We can proudly say that these methods succeed in almost all cases in repairing common mesh problems, but as they are automated repairs, you might want to have better control on how your mesh topology should be modified following any repairs. Therefore when dealing with isolated and detectable errors, it is better to manually repair these errors yourself on your 3D modelling software as in rhino, the necessary tools are provided.

The reason for manually troubleshooting errors is that no automated algorithm knows your mesh as accurately as you do.

Next, the tools Rhino provides to solve the most common problems with invalid meshes will be discussed in the coming paragraphs.

3.1. Mesh reduce

If your mesh’s ‘Number of Polygons’ is more than a 1.000.000, it will be quite difficult for Sculpteo to handle it which also means it contains unnecessary details. Therefore, you need to reduce this number through the “Reduce mesh” command Rhino reduce mesh.

Rhino mesh reduce

You will have to find a good balance between your model quality detail and the polygons number because the more you reduce the mesh the more it will become faceted.

3.2. Mesh orientation unification

The faces belonging to the same shell of your model might not have a coherent orientation, which means that the normal direction of your faces are not the same as it was explained before in the “Coherent Mesh” section. In order to fix this issue select your model and use “Unify mesh normals” tool Rhino unify mesh normals this will put all the normal direction to the same side and will eliminate the problem.

3.3. Mesh hole fill

After running a test with “select open meshes” and “naked edges analysis”, you have find a hole and its location in the mesh. As your mesh should be closed and “watertight” to be 3D printable, the hole needs to be closed. In this case you can use the “Fill hole” tool Rhino hole fill.

Rhino hole fill

3.4. Non manifold errors

Once you have detected a non manifold edge or faces you can eliminate the excess edge or face. It is recommended to observe the model in the wireframe mode because frequently the non manifold edges are at the interior of the object as in our example. In this case you will have to eliminate the two extra faces that are sharing the edge.

Rhino hole fill

It is made evident in the illustration by red colors for the explanation. You can eliminate them using “Delete mesh faces” Rhino delete mesh faces located in main left bar ‘Mesh Tools/ Delete mesh faces’ or typing “DeleteMeshFaces” in the command line. You select the face and you tap enter to finish the operation.

Rhino non manifold errors

Rhino non manifold errors

3.5. Multishell parts

If your model parts meshes are made from multiple shells this may cause a problem when creating a 3D printable file. In this case you should separate the shells to verify if they are expendable.

Rhino multishell parts

Rhino multishell parts

Rhino multishell parts

If not you should integrate them to the main shell, for this you can use the command “mesh boolean union” Rhino mesh boolean union which is available on the main left bar Mesh from surface polysurface/ Mesh boolean union or typing in the command line “MeshBooleanUnion”.

Rhino multishell parts