Little bugs in the tutorial:
"sube" should be "cube"
"undoubtably" should be "undoubtedly"
"containind" to "contained"
"vizualisation" to "visualization" or "visualisation"
"remodelling" to "remodeling"
On the subject of manifold surfaces, it would be good for you to point at the original tutorial,
https://www.shapeways.com/tutorials/things-to-keep-in-mind. In that tutorial, I had a question: you show a Blender operation to make the object non-manifold. What does this operation do? Does it simply move the two touching edges back a bit from each other?
I'm looking forward to unleashing the mesh manipulator MeshLab to clean up my meshes, so I want to understand "manifold" a bit more in other packages.
Eric