Adding height based on distance from edges?

Hi all, architecture student back with another question. Big thanks to this community for being so helpful so far!

With the help of some of the folks here, I’ve got a 2D site area that I’ve now smoothed out nicely. I’m now looking to essentially loft the site in 3D with the height of any point set by its distance from the outer edge of the shape - up to a set maximum height.

Is that possible? I’m currently working on offsetting the shape inwards to essentially create contour lines and loft those, but I’m sure there’s a better way of doing it. Thanks!

Urban Proposal v7_forum.3dm (663.7 KB) Urban proposal (12.9 KB)

I don’t work with R6 (nor I have any add-on of yours) but maybe you are after something like this?

Urban (139.7 KB)