Can anyone help me with this, please - it’s driving me crazy:
I created all the outer walls, removed the windows, and then extended the walls upwards using the push/pull tool. Then I am removing the extra lines from the doors/windows. I was successful with all except one wall which removes faces when I remove the extra lines.
Please share the file here so we can see what you are dealing with. Otherwise we can only guess.
That looks like the wall is not flat, but, again that’s just a guess.
I can only add an image at a time, so let me add the first one, then the selection of the lines, and finally the result (which is the image I just shared).
After creating all the outer wall using the push/pull tool, I am left with the windows and the extra lines. I deleted the extra lines for almost all the windows and it works, except for these 2 windows here:
Images aren’t enough to really analyze. Please upload the skp file.
here it is!
testing-3d-plan.skp (318.8 KB)
In the attached image, I have done two things: I turned on view hidden geometry and I labeled various vertices using the text tool. This shows that my guess was right: the wall is not flat where the windows pierce it.
I also notice that the coordinates of the points are strange values and that snap to length it turned on in the units settings. That combination is a sure path to strange errors because once any point is inaccurate, snap to length will propagate that error to every edge drawn from it. The length is exact, so if you go 100 cm from 5.04576cm you will get 105.04576!
@slbaumgartner thanks for this – sorry, I am a complete newbie on Sketchup. What are the steps I need to take to fix the issue? I have already turned on ‘view hidden geometry’, and I understand the wall is not completely flat, but not sure what to do next.
Not sure if this was intentional, but also noticed one side of the building is 1 mm larger/smaller then the other side.
Also noticed the walls (on the issue side) is not exactly 300 mm
Maybe wise to copy the window-openings to the side and redraw this wall section again and cutout the window-openings again.
After repair the sizes are matching again 
Fixed Version:
testing-3d-plan-fixed.skp (252.4 KB)
Ahhh, I’ve no idea how there was different sizes, because I first drew the outer layer, and then used the offset tool and set it to 30cm, and that’s how I created the outer wall… but this is awesome, thanks so much @AnnoNiem 
To help achieve your goals, some time spent at the SketchUp Campus and at the SketchUp - YouTube channel will be very worthwhile. Both sites are from the SketchUp team. On the YouTube channel, pay attention to the Square One Series and Level UP series. They cover the basics for each tool.
You’re welcome, glad i could help (for a change) 
Sounds great - thank you!
It looks like @AnnoNiem has set you on the right path. The differing dimensions cause the outer wall adjacent to that side to be out of square with the axes, and that starts the ball rolling with further problems.
Tracing lines off an image is not an exact process in SketchUp because lines in the image are just pixels, nothing that SketchUp can snap to. So, you have to use extra care until you get enough traced that you can start using the image just as a reminder and instead working from inference snaps to what you have already drawn.
So, for starters, you need to make your best effort to align the image with sensible coordinates in SketchUp. Draw guide lines parallel to the red and green axes at distances that would make sensible locations for two perpendicular walls. Then move the image so that the lines of those walls align as closely as you can to the guides. Zooming in close helps.
Set the units in SketchUp to display more decimal places than you actually need so that you can see when small errors occur.
Now draw trace the two reference lines from the image using the SketchUp line tool to draw along the guide lines. Check the end coordinates of the end points using the text tool to verify that you got what you intended. Move end vertices or whole lines as necessary to get good values (be careful to lock axis direction when moving them).
Then, as you add more lines using the line or rectangle tool enter precise measurements for dimensions. You can use the tape measure tool over the image to see approximate measurements and then round them to the nearest sensible value. Wherever a wall line in the image should be parallel to a model axis, use inference locking to make sure the edge you trace is along that axis direction. As more edges are added, you can usually use inference from the ends of existing edges to get new ones exactly matched to them.
This has been really helpful, thanks everyone for taking the time to read my scrappy message and reply in the most helpful way!
