Snap or project bezier curve to mesh surface

Question

I've got a curve which follows the edges of a mesh. This curve is done manually, and I'd like to keep it this way. The mesh has no edge loops that I can use to duplicate them and separate them to be used as a curve.

I'd like to make the curve to follow the actual surface of the mesh, the front part. I've tried using shrinkwrap modifier into the mesh, but althought it has worked for me once with a curve, it's been impossible to replicate that with other curves:

With shrinkwrap, it's a mess no matter which settings I use, and it just deforms the mesh and snaps back and forth without any control:

I've tried also to "draw" the curve with the "Surface" checked on the Tool menu, but it's not accurate enough and as soon as any point is moved, it just leaves the surface. And I've tried various modes of "snap" mode without success.

Is there any way in which I can draw the primary shape of a spline and project it in a mesh surface, just on the front face of it, and be able to modify it without losing that "snap"?

Thank you!

Answer 1

I won't mark it as answered because maybe there are some other ways to achieve this which are more accurate.

My solution finally has been to try different modes on the Shrinkwrap modifier (mostly Project and Closest points, with Outside surface option selected), and moving the curve until I get something close to what I need.

Once got that, I would Convert to Mesh (it will apply the modifier, to avoid final shape to be distorted because there are not enough points). Here I had sometimes to use another Shrinkwrap modifier again just to solve some missalignments, and Convert to Curve.

Finally, for the latest adjustments, just turn on the Snap feature with Snap to faces and isolate the objects so the only visible objects are the curve and the mesh you want to snap it to. Enter edit mode with the curve selected and move the unaligned points so that they stick in the surface of the mesh.

They seem a lot of steps, but they're pretty straightforward and quick to do once you get it.

To sum up:

1. Shrinkwrap modifier until you get close to what you'd like
2. Convert to Mesh
3. Apply another Shrinkwrap modifier if needed
4. Convert to Curve
5. Hide everything except mesh and curve
6. Activate Snap feature, with Snap to face
7. Select the curve and enter edit mode, and move the unaligned points

Don't forget to Apply all transforms when you're done!