Tunnel help

So I've been wondering how do people make those tunnels that go under ground. Because when I make a tunnel that goes under ground, it goes through ground...[sillyme]



P.S. Sry for my bad English

they are made using 3ds programs like google sketchup or the object creator. personaly i've never tried to make one. always wanted to, but never learned how

I know how to use google scetch up but I don't know how to put them in Nolimits editor... Can somebody help me?

[hyyyper]

^you need the pro version to export SketchUp to 3ds (the format NL uses)

But do you first open them in a program like 3ds max, to get the textures, because they don't work if you put directly in NL.

Do you have some solutions for that?