Sometimes, there might be holes in your 3D model, even if it was created with 3D modeling software.
It just happens.
Especially when you export your model, it goes under a change of mesh.
That’s when small holes can appear.
Frequently, your 3D model lacks in facets and that’s because of two elements overlapping each other. This is the result of a wrong crossroad between two elements.
Another problem is when you combine 2 items together and along the blending line, there’s a hole. The program did not create the facets in that place.
Holes may create, also, when you’re selecting the parts you want to delete and accidentally select a part of your other item. In this case, the crack can be bigger or smaller according to the size of the facet you mistakenly selected.
We’ll see an example of a 3D file that has a lot of holes.
Anyway, SketchUp has a useful item, the Pencil item, that can help you close the cracks, by re-drawing the triangles where needed.
The item Pencil is especially useful to fill up the gaps. As I said before, connect the dots of the triangles to create the new surface.
The picture below shows how MeshMixer signals errors like holes. As you can see, the holes are surrounded by blue color.
As I explained in the last lessons, a hole in the 3D model is a problem because the inner and outer facet must be kept divided.
Here we can see better the Analytic function. It detects exactly where the hole is.
Sometimes you cannot auto-correct the errors. When this happens, you need to manually create the missing facets.