Occasionally I run across a STL that S3D slices a bit funny. This model is a good example. It is a plate for an Arduino with raised mounting holes, via Thingiverse. While visually a solid, the mounting holes slice with "bridges." Here's a screen shot showing the difference.
When I load the STL into MeshMixer, I can orbit the model and see there is a thin line between the hole's extrusion and the model base.
I don't know how to "fix" this model so that S3D see it as continuous. Anyone have some tips on what to do with a STL like this one?