Ok, there are two parts to the issue you are having, one part is an issue with my code. I just released version 0.8.1, that fixes one of the issues that was causing it. Another issue is how you create the plane.
You can see that on two of the faces these planes don’t line up. Meaning that your planes are skewed and that the add-on won’t work right. Make sure that all of the groups of faces are in the same plane.
Is it possible to take roof angle from the helper object, because its easy to face snap to the roof face ?
Or have you tried to take roof face normal and set helper object automatically to the correct angle.
How does the add screw head function work on the tin? Seems to being doing weird things. If you create new tin siding and leave the default size ( 20’ x 8’ imperial ) and add screw heads, it only places them on the left half. If you double or triple the width to say 60’ , it only adds 4 or 5 screw heads on the very bottom.
I rewrote all the code dealing with the screws and it is now working for me, so check out version 0.8.3 and let me know if everything is working for you.
Very nice addon! I just found this. Two suggestions: an option to turn off some limitations in the options. A uv option to have similar geometry occupy the same uv space (steps of the stairs for example)
So I just released version 1.0 of the add-on, a short breakdown of what all was changed can be seen my main post. I am also hosting the add-on on GitHub now (finally…). There are almost certainly some hidden bugs because of all the changes I made, so if any are found, please let me know so I can take care of them.
Ok, so I looked into this and everything is behaving as intended. There are two issues here, one is with your mesh, the other is a limitation of my code. The face that the 3D cursor is over in your image, is not in a plane, which can be seen in my image below. Whenever I try and manually place a plane to cover that face, it cannot, because one vertex is, as I mentioned earlier, not in a plane with the others. So the add-on cannot handle that, unless you split the face into two faces, and handle each by themselves.
The second issue is a limitation of my code and how it handles lining things up. The vertices of the face to the left of the 3D cursor, in the separate piece, are in a plane I believe, but it is tilted in such a way that makes it much harder to line up with, and my code doesn’t account for that specific type of tilt. This is something that I won’t fix as I’m not sure how, as the math is pretty complicated and this is kind of an edge case.
So short answer, your mesh is a little off, and I didn’t write code to take that into account.