I was chasing an offset problem in a residential roof connection. One perpendicular connection wasn’t lining up the way I expected, and the valley steel was cutting off. The other side made the problem especially confusing: similar geometry, different result.
There was an obvious place to investigate. The connection code had separate handling for different segments, with offsets that sounded very much like the thing I was trying to fix.
A reasonable change, with no visible effect
We first focused on the top-left region connection offset. I made the suggested change and checked the result. Nothing.
Then I stepped through the code and found the detail that changed the whole discussion: this case was only hitting the bottom chunk of code.
That was a much more useful observation than another screenshot of the same broken roof. We had been discussing a change in a branch that wasn’t responsible for the case I was running.
Follow the actual path
In geometry code, names like “top,” “bottom,” “left,” and “right” can be easy to over-trust. They describe something in the implementation, but the connection on screen doesn’t automatically tell me which branch produced it. I need to follow the inputs and execution path to establish that connection.
Once we moved the investigation to the branch that actually ran, the next adjustment appeared to fix the connection issue. My next question was about the rake trim, which was still missing on the right in a flush attachment case.
That distinction matters. The offset result looked right; the trim was a separate remaining issue. I don’t want to turn “that part seems fixed” into “the whole roof generator is done.”
The check I want to do earlier
Before changing an offset formula, I want to identify the failing case, put a breakpoint where I think it’s handled, and confirm that execution gets there. Then I can inspect the values used by that branch and compare the result against a case that already works.
There isn’t a general-purpose offset formula to paste here. The useful part of this problem was the debugging step: establish which code owns the visible result before trying to correct it.
I can spend a lot of time reasoning carefully about a formula. If that formula never runs for the case I’m testing, none of that reasoning is going to move the roof.