Relative Elevations For Level Lines?

[Limbatus]

How do I add relative elevations, or project elevations to my model. I'm working on a site which is 850 feet above sea level, but I'd like to list my basement elevation as 0'-0". thanks in advance - Court

[Limbatus]

OK well I'm smart enough to have figured this out on my own. so you no longer need to answer my initial question. My next question is this.... Can I have both elevations in my level lines actual + relative?

[twiceroadsfool]

Nope. Were wishing for it too.

[Alex Page]

What we do is make a level called "Datum", at the correct 0 height, then do a spot elevation on the level line using the "base" as 'Datum",
See jpeg for example - obviously you can make the "extra" symbol look how you like etc.

Not as versitile as an "automatic" one, but it certainly fills the hole

[rtaube]

I haven't tried this, but can you do you what Alex suggested above and create a datum level as the 0-0 for the project. But then also create a shared parameter with the true elevation height for that datum level. Then add a parameter to your levels that is a formula adding the current level height to the shared parameter height, and outputs the overall elevation along with the relative elevation?

Just a thought, not sure how much one can mess with the Levels family