I mean, its only possible to place walls on one of the 4 sides of a foundation, i want to place it anywhere on a foundation with any rotation when holding shift/strg (or any other button you want) (disable clipping feature)
and the same goes for machines, just because i place them on foundations that doesnt means that i dont want to rotate it anymore.
(Edit: Iam not very good in english, if you want to rewrite my suggestion to make it more understandable, just do that and post a updated version in the comments. I will eventually replace my suggestion with the new one.)