Hi Juan, I expect to add a set of "analyze" tools in version 2.0, including length and distance tools.

For now one way is to draw a line and watch the distance control in the bottom toolbar, it will show you the distance to the previous point. You can also activate distance constraint by entering a distance there.

Petr also has made a custom command for measuring a length, you can find that at his page here: http://kyticka.webzdarma.cz/3d/moi/ , look for "Measure Distance".

- Michael