the functions of some Mesh Import Settings

Hi

I am making a true earth scale longitude and latitude system to do a type of google earth with my phones gyroscope. As you can see the model can be fairly large and difficult to work with.

Something I noticed and a few questions I have regarding import settings.

I had noticed on default settings some verts were automatically merged on import, and the culprit was two import settings that needed changing.

this was OPTIMIZE MESH, and WELD VERTICES

it screwed with my vertice sort order. Although it is fixed now, I had a question about a third import setting.

INDEX FORMAT with a choice of 16bit 32bit or automatic by default.

I take it that Weld Vertices was the main culprit for removing two vertices that represent the farthest pole coordinate, it had merged them into one as they were so close together by default. But I wonder exactly what optimize mesh is doing, and how to use Index Format, or how to judge which index format is suitable.

If anyone could give as much knowledge as they can on any and all import settings, even ones not mentioned. I’d be very grateful.

This was a stupid question

I managed to resize to workable scale and produce google earth though the two import settings are relevant

Still uncertain on difference between the 16 and 32 index format though