Adventures across the 3rd dimension

Alt+D was it - it moves the vertices/edge - the other rip option required polygons to be selected but since I had edges in one vertical line, there weren't any of those!

Edit: But it only worked once? Or maybe it never did.... It seems to just move the vertices. Again.  
*checks* Yup, I only moved the selected vertices. Damn. 

Edit 2: tried copying the edge of the window into the wall mesh but I can't actually link the vertices/faces without everything looking wonky again. So I tried copying a whole section of wall that already had a window, and to connect the edges of that section to the sides of the original wall and deleting the original wall once the vertices were used ut apparently it was the wrong vertices or edges or something because it still looked like shite. 

I'm sure there HAS to be a way to do this. Grrrrrrrr.  
(I did notice, though, that the shading around the original windows isn't 100% perfect either... Just not anywhere near as bad as my results)

Alt-D seems to be a combination of Rip and extrude. Or something.

Going back to the subdivision, when you are moving the subdivided vertices are you keeping them in the same plane by using the vertex/edge slide (pressing G twice rather than once)?
Otherwise it's a mystery why that would change the shading.

G?

They're in the same plane (Y) but have to be moved along X and that changes their "relative" position along the Z-azis, if that makes sense?

(Edit: I mean since they don't change position along the z-axis, they don't follow the previous edges... )

You don't press G to move things?

If you press it twice then it switches to edge slide mode which restricts the movement to within the existing face so that it doesn't change the normal.

I click the colourful little arrows to move stuff in the direction I want. Or I just type in the numbers in that box that was missing recently.

Charlotte wrote:

 Or I just type in the numbers in that box that was missing recently.

I think I might have figured out why the faces look all wrong on that wall... Even if I follow the advice of using edges instead of vertices for connecting faces, there are also duplicate edges, so I have to make sure to use the right ones. So fixing it all up seems to be possible but terribly fiddly.

How can you have duplicate edges?
Isn't that just the same as duplicate vertices?

Do you need to keep all the duplicate, unconnected bits for importing back into the game or can you just Merge By Distance to get rid of them?