Starting with iso lines

[ElThommo]

I thought it would be usefull to share my initial experience with Iso lines.
It was easy to see how pick up th marker and define areas but what kept happening was I would define an area, set the target height and then click on generate, what would happen then was that no matter what the target height was set at, the new generated terrain would be flat inside the defined area. It was only with some amount of trial an error did I discover that the defined area needed to be reselected with another tool before it would work properly. Perhaps a tool tip pop-up pointing this out for new users?

[cajomi]

Well, the isolines are no isohyphen. That means, if you draw a great circle, you will see the circle as an unfilled circle, like a crater for example.
On the first glance, this might look like a disadavantage, but at the second view, you will see, that you do not need to define closed areas, but simply do some strokes, to define ridges, rivers and so on. This is a much more free approach like defining closed areas. If you need a closed area, well fill it with some strokes.

To the workflow:
First set the height, then draw the line. Else you have to select afterwards every line, and define the wished height.

You can change every line afterwards from a one heighted to a two heighted line, by simply checking the second height and setting the height with the slider.
When you select a line, the sliders adust to the height of the line. This is comfortable, if you want to draw lines with the same height. Just select a line, switch to the pen tool, and draw a line.
You can also use the alt key, to pick up a height from the terrain. Just move the mouse in the 2D view around while holding the alt key.