This happens to me just about every time I’m working on a model after a few days into it, without fail. Say I create a window frame; there are many many ways to go about creating a window frame-like object, but let’s I do it this way… I start with a 3" x 1" rectangular plane and extrude it 3’. I then copy an end-line back towards to origin 1" creating another rectangular plane on top of our extruded box. I extrude that plane up 3’. This gives us a 3’ long by 3’ wide “L” shape… All the while maintaining orthagonality with the UCS snaps. You can see where I am going with this…
The issue: When I am extruding the last plane downwards to complete the last side of my window-frame the planes don’t match up. They are off! They are off by less than 1/64" of an inch but nonetheless they are off. They are off by enough that for the rest of the time I’m building this model I have 2 snap-points that are almost indistinguishable from each other. Two snap points for planes to build from. Two snap points that leave me ripping my hair out because planes that SHOULD be appearing are not.
This doesn’t just happen with extrusions either. I’ll run a line along a UCS guide 25’ and the line will be not follow. It will appear to follow, but when you measure to a supposedly parallel line, they are not parallel. It makes creating a complex model nearly impossible.