Hi Michah,
You would not believe how hard I tried to make it so the rule did this.... I have previous draft rules that I made in my spare time that experiment with this concept, but the problem is stability is hard to keep because alignment changes when you try to connect to multiple streets (the edge indexes changed for some reason between different segments starting and ending points...it was bizarre). So the behavior you are experiencing is the EXACT SAME I did. I was frustrated for weeks about this, and actually am glad to share that with someone else. When I first started on the path to try to do this, I did not know much CGA and deferred to an envelope function (made sense at the time and still might). Since that time, I have come up with ideas I have not tried yet. List below.
General Strategies:
I would suggest printing the edge indexes and seeing if there is any pattern with the various street parameters (connectionEnd vs. connectionStart).
See if alignScopetoGeometry can be used to anchor your orientation based on some discernible pattern.
1. Extrude up, comp sides and do a roof shed function on the side facing the street, but if it is not stable ALL SIDES (because if it goes into the intersection, you won't see it because the shape is above it,and on the sidewalk curbs, it should be under the sidewalk).
2. Extrude up, comp the top, comp the relevant edges (or again all edges if you have to), and insert a sloping object whose's height is equal to the sidewalk height.
3. Comp the top, try different alignScopestoGeometry, use the setback function on the appropriate edge, and make the border a sloped surface (angled split or roof shed), and then extrude the center to the appropriate height.
If you try this and any of them work let me know! I can't tell you how much I sympathize with this effort.
David
David Wasserman, AICP
