collada, sketchup and geometries

Hi everyone,

I’m new to using collada, actually I am doing some experiments with webgl, and I use Sketchup to do the modeling, export to DAE, and view the models through three.js and webgl.
What I don’t understand is how geometries are built, or “decided”.
For example, if I write a basic webgl html/javascript page with a simple cube, I can see, using some stats module, that there is only one geometry and 12 faces. Fine and logical.
If I create a basic flat triangle in Sketchup and export it to DAE, when I import and view it with some three.js code, it tells me there are 3 geometries and 13 faces!
I really don’t get it. I hope I was clear enough (I am not english fluent!) Please can someone help? :wink: