Surface

This object is used for triangulated surfaces such as STL files.

https://commons.wikimedia.org/wiki/File:EiffelTower_fixed.stl

Here is a very simple example of a triangulated surface.

Use the gear menu on this object and click Extract Data. This will create a Table object.

The table contains a list of vertices (red dots) and a list of triangles that are stored as references to the points. For example, for the above shape, there are 14 points. Each point has a vertex and a surface normal. The normal is used when rendering the surface.

The triangles are stored as offsets in this point list.

The reason the index here is 0 based is because typically you only need this when you are debugging and in C++/Python the index is 0 based.