Again, n00bish terms.
Pic 1, build you wall completely. Slide it into place (pic 2)
And just select the corners (round circles) and weld. ONLY select the corners! no lines or faces.
Afterwards, tes…
Oké awesome that worked. Funny enough, it was a combo of your explanations that did the trick for me. For other people who have the same problem, here is the n00b explanation:
In picture you see that none of the frames i want to 'combine' have…