How can I create this Offset path?

Question

I've been trying to reconstruct this offset path effect in Illustrator but I haven't been able to.

I can't get it mathematically or optically to work. I'm both interested to know how to achieve the offset part and how to create the overlapping parts as well.

I'm using Illustrator CC.

My construction so far. Made the offset work with the Appearance Panel. But the cutting is not accurate.

Answer 1

Starting from two ellipses, in this example:

stroke weight = 20 px / fill = none

Duplicate moving them vertically and connect them like the image below:

With the Direct Selection Tool > select all the center points

Menu Edit > Copy

Menu Edit > Paste in place

Move horizontally pressing Shift + right arrow

Delete the two top right points and the two bottom left points.

Join the vectors middle points: with the Direct Selection Tool make a frame around the top middle point and press Cmd+J (mac) / CTRL+J (win). Do the same with the two bottom middle points.

Select the two vectors and blend them with just one step to create the middle vector:

Menu Object > Blend > Make

Menu Object > Blend > Blend Options > 1 step

Menu Object > Blend > Expand, to get the three vectors

Menu Object > Ungroup

Move back the middle vector to the main figure center pressing Shift + left arrow

Stroke white (yellow on the example), weight = 18px

Move back the other two vectors, red on the image below

Selecting those two vectors, from the Appearance Panel add another bottom stroke, weight = 40px (green on the image)

Using the Selection tool, press Shift to select those two vectors + the top ellipses + the bottom ellipses

Menu Object > Arrange > Send to back

Change the stroke colors:

Answer 2

This answer is quite similar to user287001's answer, however this uses an art brush to create the initial strokes, and finishes by simplifying the paths to reduce the number of anchors.

Make an art brush from black and white filled rectangles as shown below.

1. Draw ellipses, and apply the art brush. In the example I have two different size ellipses, but with the same brush applied. However there's no reason the ellipses couldn't be identical. I just thought it would look better if it's supposed to look like a letter/number.

2. Expand appearance

3. Open the Pathfinder, and hit Divide, then Ungroup. Then fill in the shapes that should be white, and those that should be black.

You could stop at this point, or continue the process of cleaning up so that you end up with single paths filled black, and no white parts left.

4. Delete all the white shapes

5. Use the Shapebuilder Tool to unite all the black parts.

6. Object > Path > Simplify to remove the unnecessary anchor points.

Answer 3

1. Draw the smallest ellipse. Here it has 10pt wide stroke. Draw a horizontal line a little above the bottom anchor point of the ellipse and insert to the ellipse 2 new anchors at the crossings (=in the red circles). Remove the line.

2. Convert the bottom anchor of the ellipse to a corner point (the conversion tool is under the pen). With the direct selection tool drag that anchor a little downwards to have the right curve direction. The inserted anchors are guards who limit the affected area

3. Make three 10pt wide offset paths (orange, cyan, green). The offsets are 10pt, 20pt and 30pt. Group them temporarily to get step 4 done easily.

4. Make a 180 degrees rotated copy. Select it. With the direct selection tool just after selecting drag the copy to fit. Drag the top anchor of the cyan curve to snap with the bottom anchor of the orange curve in the original group. Have smart guides and snap to points on, no other snaps! Cursor color shows the snapping.

5. Ungroup all. Convert all paths to outlines. Select all. With the shape builder combine the parts. Have a new fill color (=black) to see the result clearly

6. Remove the extras. Done.