Comment by crote
> For me FreeCAD was highly unintuitive. Everything is a chain of operations/modifications on solids(good!) but for some reason it won't let you modify anything but the last element in the chain?
This has been a longstanding issue in FreeCAD. A big issue is that it is really difficult algorithm-wise to deal with changing geography: a tiny change might result in two objects which look the same, but have a completely different internal representation. If the next operation is attached to "face #23", it's going to freak out. This is called the "topological naming problem"[0], and it is pretty much impossible to solve completely.
FreeCAD itself can support the kind of parametric modeling you want, but because it's so fragile the UX is pretty horrible. To do it properly you essentially have to specifically design your entire model around being parametric from the start.
Luckily FreeCAD made some massive improvements in 1.0, and issues due to topological naming are now far less likely to occur. Hopefully it'll eventually turn from "guaranteed to ruin your day every time you try altering something" to "might need some manual adjustment in weird edge cases" - and that would also make it far more sensible to invest in UX for making mid-change modifications, or for modeling using variables.