Trim/Extend to T

While testing Trim/Extend to Corner on the house, I kept finding cases where one wall was already right. Moving both sides solved the geometry and spoiled the model.

That's the reason for Trim/Extend to T: one boundary stays where it is, and the other line or wall comes to meet it.

You pick the boundary once, then click each line or wall you want brought to it. The boundary stays picked, so a whole row goes one click at a time, and each click is its own undo step. In Revit terms, it's Trim/Extend Single Element, and Multiple Elements without the selection box.

The part that took the thought was what should happen when a wall lands on another wall's run rather than at its end.

I could've treated that as nothing more than a trim and left the two walls touching. But then the visible result would look finished while the wall itself wouldn't know that it had joined anything. In Revit, Trim/Extend moves the wall end first; the automatic join fires because of where that end lands. I kept that order.

The tool brings the end to the boundary. If that boundary is a wall, the arriving wall is then joined there as a T. The wall it ran into stays as it is, and the arriving wall is cut square on its face.

That order also lets the same operation work when either pick is only a line. The Tool Page has the complete interaction and supported combinations.

I'm testing this against walls drawn with Muzwalls, Medeek and FlexTools, and against layers grouped by hand. That's still a small sample. I'm sure to discover lots more edge cases when using the tool in my modelling work and even more once it's in the hands of other Sketchup users.