For round bottle:
Create or open the main body.
Add a sketch to right or front plane.
Draw a rectangle. It must be vertical to the axis of rotation.
To produce the same wavy lines on the base body, the rectangle must be constructed according to the equation e=√2 * l, where e is the corner dimension of an imaginary square and our diameter.
Solved to l---> l=d/ √2.
In my case l= 60mm/√2 = 42,43mm
Add the wavelines
Now you have to use the "project sketch" method.
Just select the wave-sketch and the face of the rotation
If u done it right, you have to add a plane on the end/ startpoint of the projected line and the line itself
Create your cutting-geometrie. remember to plug the geometrie on the projected line and the outer edge.
Cut the geometrie along the projected line.
At this point it should look like this.
Since the cut only goes through a quarter of the surface, it must be arranged rotationally.