How to make one path exactly go around the other?

Question

Adobe Illustrator

There are two arbitrary organic shapes

. How can I make sure that they are exactly in contact with these envelopes? Those. so that the left blot would flow around the right one (not completely, partially, but exactly along perfectly)?

Answer 1

Create a parallel path for the right shape with an offset of 5px, let's say
Draw an ellipse according to the shape of the left figure
Move parallel path on top of all objects
Subtract a parallel path from an ellipse
ready
finish the corners with rounding and a pen