Seamlessly connecting two paths with different stroke width - Illustrator

Question

I'm sure the solution to this will be incredibly simple but I for the life of me cannot figure it out. I'm drawing a basic floor plan and want the interior walls to be a thinner stroke than the exterior.

I expanded the outer wall (red) so that I can snap the interior wall (blue) straight to the corner, however obviously unless the path is closed I can't offset it or use align stroke. I don't want to join the paths as each will be on a different layer.

What's the easiest way to solve this so it appears/snaps seamlessly?

Thanks :)

Answer 1

If the exterior walls (red) are expanded and the interior walls (blue) are stroked paths you will not be able to get the kind of snapping you are wanting.

1. If both exterior and interior wall paths are expanded you can go to View> Snap to Point and then grab the path you want to move by the corner you want to join and it will snap to the other path corner anchor point. This seems a difficult way to draw walls unless you are good with the White Arrow (Direct Selection Tool) and can extend/ shorten/modify your walls easily.
2. Another option is to leave both the exterior and interior walls as they are. You can snap the anchors. Select the interior wall you want to align with the Black Arrow Tool and hit return to open the Move Dialog box where you can move the line up or down numerically to align it.
3. Honestly either of these options is a hard go of it and if you are doing this as a "one off" project then I suggest you leave your shapes and strokes as they are and just zoom in and manually align them where you want (with snapping turned off).

Answer 2

A brute force solution.

Have a corner adapter with new anchor points inserted to the right places:

In this case the stroke widths are 2,5 mm and 5 mm. The green adapter is a 5 x 5 mm strokeless square which has got two times Object > Path > Add anchor points.

The exact placement on an unexpanded stroke is based on the centerpoint of the adapter, so centerpoints should not be disabled. The same adapter works also if one of the strokes is expanded.

A 50% smaller piece would do the job, but the bigger one is handy because it covers 4 directions. In the next image one is made for line widths 4 mm and 6 mm:

4 copies of a 2 x 2 mm square are placed to the corners of 6 x 6 mm square and all is united with the pathfinder panel. In the right the result is used.

You can reuse the same adapter or let it be in the corner. Let the adapter have an unique and well visible color; all of them can be selected easily with Select > Same > Fill color.

Answer 3

I'm doing a lot of floor plans myself and this is always a bit of an issue.

I ended up giving up the search for the perfect perfection, and just keep the strokes as strokes (not expanded), because the thicker stroke will always hide out the areas of intersection.

You can always move the anchor points to snap and then manually adjust the Y value at the other end of a line (keyline mode helps), so it remains 100% horizontal, but this can get tedious if you have many plans or complex artwork.

You can also shift the lines up or down using the Transform panel, edit the Y value with an amount easy to calculate based on the actual thickness of the lines.

If your plan is "basic" and there's only one, it may be worth doing some manual adjustments like this.