that's a good trick, nesa, thanks. but that wasn't really my problem. i don't mind having a mesh floating horizontally in a big virtual vacuum while editing it. the problem was it was horizontal when i imported the mesh into my game. (see picture1)

Vernarancs82, you don't need to use an older version of simpe. you have to change the order of the axes to XYZ (see picture2) before extracting the object file (step 27). that way i will be exported horizontally and the mesh tool will import it correctly. (btw, just like greenleafcat said, i also use the 'export' butten because i don't find the 'export to object' and it works fine.)

i finally managed to make my first mesh. (see picture3)