Tips for creating carved guitar tops using Sub d

Hi everyone.

I’ve been exploring the use of Sub D tools to create arched surfaces for guitars, but I’ve been running into a problem that I don’t know how to deal with. The problem is that once I form the arch or “carve” using Sub D, I can’t figure out how to then “snap” the surface edge to my original outline to create a coplanar edge. I found several work arounds using some of the standard surface tools (sweep 2, network srf, patch), but it sort of negates the main points of using Sub D for me, which are the ease of manipulation and smoothness/continuity of the surface. I’ve also tried SetPt at the recommendation of Abraham Wechter, and Join Edge as another recommendation from my friend, and neither seems to lead to a suitable result. I figured it’s worth noting how I’ve been working up to the point of my problem.

I create my guitar outline, patch it, convert it to Sub D, manipulate the Sub D surface into a suitable arched surface, project my outline onto the Sub D surface, and trim it using the projected outline, which then converts the Sub D surface into a poly surface.

This method in and of itself may be leading to some inherent problems, but it seems to be the only way I’ve found so far that lets you utilize the power of Sub D while skirting Sub D’s proclivity to create surfaces with inexact outlines (enabling me to retain my exact outline).

Sub D info pertaining to guitar building seems to be scarce, so any comments or recommendations you may have would be greatly appreciated.


Hi @Benjamin_Kahler

That looks like a Patch (NURBS) surface not a SubD. The accuracy to the curve used will be based on the density of the patch’s control points. Patch is not ideal for staying put on a trimmed border though. If you are working with SubD surfaces, make sure to use ToNURBS first and then trim that result with your curve. If it is too far to join into your adjacent model, you can offset your curve and trim again creating a gap large enough for BlendSrf to bridge the gap comfortably for you.

If that doesn’t help, please post a 3dm file to explain more about what you want to do in the model.

Carved Top Demo.3dm (163.2 KB)

Thanks Brian. The surface included in the file is a NURBS surface, but it seemed like it would be easiest to demonstrate visually what I’m trying to do best through it. I’d just like to be able to terminate the edge of the trimmed subd surface that I’ve converted at the outline that’s just below the surface.

I’d suggest using QuadRemesh on your trimmed surface to create a SubD from it. Edit that to get the shape you want and keep the edges as close to your curve as possible. Then use ToNURBS on the SubD to make a packed NURBS polysurface from it. After that, Offset your curve inward and use that to trim away some of this open polysrf you just created as seen from the Top view. This will provide you with a gap to use BlendSrf over. You will need a surface edge or chain of edges to blend to so extrude your original curve down to make a surface edge to blend to. Keep the continuity for that edge at positional in the BlendSrf command and then Join the result.

I hope that helps.

1 Like

Hi Benjamin,
I’ve been modeling some guitar tops using subDs.
I’ve include a quick attempt to match your surface.
Here’s how I did it:

  1. Create a loop of flat faces around the edge of the surface outline. (With “reflect” on)
  2. Move the outside points to match the outside surface outline. It won’t be exact, but you can get pretty close.
  3. Insert an edge loop. (If you keep the outside faces flat to the construction plane, your surface edge will be tangent to the construction plane)
  4. Raise and rotate the inside edge loop to get close to your target surface.
  5. Bridge the inside edges to fill the hole
  6. Manipulate the inside points to match your surface. I had to insert an additional edge loop to get close.
    Hope this helps,
1 Like
1 Like