How I can make a curvy flat plane for an ankor?

Question

Ι am making an anchor ornament and I want to desighn the curvy part of it:

But I have no idea on how to make this part. What I want is to extrude some sort of flat 3d object out of the background image:

Answer 1

Create two curves, the baseline and the profile.

Baseline:

Create a bezier circle, disable cyclic, notice how it changes the shape due to having auto handles, so after rotating it to be symmetric on $y$ axis, switch the handle types to FREE and only then delete the two excess vertices.

Profile:

Just duplicate the object and scale to $0$ on $y$ axis (will translate to 0 height on $z$ axis), then also scale it a little on $x$ axis (can adjust later). Notice how I switched the pivot to 3D cursor, to make the scaling also move it towards the origin (use .D).

Now set the Bevel to this profile:

Subdivide (F9 to adjust the number of cuts), scale, move, adjust curve radius (⎇ AltS or numbers panel) to your (p)reference:

Also see:

I need help with curve modelling

Answer 2

First of all, if you have a clean image of an icon with flat colors like this you can convert it into a .svg and import it into Blender as a curve and/or convert the curve to a mesh. You can convert the image to an svg with inkscape, which is a free program. Here's a tutorial: https://www.youtube.com/watch?v=10m_2bPXa1s

Otherwise, if you want to trace this kind of detail there's many way to do it but I'd use a curve.

If you select the vertices and press V->Vector, you get the type with a straight line. Extrude them as if they vertices and place them on the sharp angles of the icon:

You can then select and move the handles of the vertices to make the lines curved:

When you have the outline done you can fill the curve by using those setting on the curve menu on the right and then transform it into a mesh with the Object drop down menu on the left top