Hello Michael,
the script with the two cylinders is working now.

Now I want the user to set a value for the diamter of the first cylinder.

I replace the value 30 of factory.setInput( 3, 30 ); by a variable lets say diameter.

Then I tried the javascript thing prompt in that way:

var diameter = prompt("Please enter a value", "10");

But nothing happens with prompt, no dialog opens nothing. Does MoI use a different command, or how to I let the user set a value?

I tried to find the answer in existing scripts but, so far found nothing.