Sorry, I had not read your second answer, I had not updated the page until I answered.

LOL! The pages that you indicate to me are exactly the ones that guided me! But I get lost with the properties of specular, diffuse, environment ... I end up with a lot of other webs open looking for meanings and in the end I do not know what I was reading ...

The textures and materials that I do not use automatically delete them when I export from SH3D as you say.

My working method is:

I make the model in SketchUp.
I export as AED.
I import the DAE into SH3D.
I modify some values ​​to fit it as it is represented in SH3D.
I export as OBJ from SH3D.
And finally I import the obj again.

The question is that in the last export / import some parameters are lost as the brightness of the materials, I do not know if it will be some internal parameter of SH3D (the slider in the material editor).

This world has a lot to learn, but it's also a lot of fun.

I just saw that you are Romanian! Your English is better than mine!

Multumesc Dorin!