Issues with FilletEdge


Hey everyone. I’m trying to put a .5" fillet on a stratocaster model and it is seemingly halfway working. The command runs, but the solid isn’t trimmed and joined even though the options are selected. I can see the filleted edge but the original square edge is still there, and I can’t use the new rounded edge to split the old surface (I guess for the same reason it can’t trim and join when I originally run it)…

Anyone know why this is happening and how to fix it?

New Strat Arm KB)



When I have this problem, Usually I do this steps:

  1. Duplicate the edges
  2. Rebuild it (to convert the polycurve into one single curve)
  3. Create a Pipe
  4. Find Intersections and in case to be neccesary create curves
  5. Trim the polysurfaces against curves
  6. Create surface (Sweep2 or Blend Srf) Maybe you need to adjust and create curves!1044&authkey=!ACVaCb2NyKGYSR8

The problem begins when you have split edges and then it’s difficult to create a continue surface

I hope this can help you

Jesus Lopez
ART Leon, Mexico


Thank you, Jesus!

Very helpful. Can you help me understand what “split edges” are? I use the split command all the time, which I thought was good technique, so I’m assuming you are referring to something different…? Also, what is rebuild doing that makes the geometry easier for rhino to work with? When I use the rebuild command, even if I keep the control point count high, it changes the curve more than I would like it to.

I imported these curves from a PDF, so perhaps that was the problem?

(Pascal Golay) #4

Hi JMBush- splitting edges refers to making single, contiguous edges on a surface (or along two joined surfaces) into more than a single edge. This happens in various operations in Rhino and can be forced by the SplitEdge command. This is may be useful to, for instance, control the target area in MatchSrf or limit the extents of a FilletEdge operation. I am not sure that this is what Jesus is referring to here however- let me take a closer look, open the model, and see if anything useful comes to mind.



Thanks a lot, Pascal. This particular model will be used on my CNC machine, but more importantly I want to understand the rhino workflow. How to make sure I’m making good, useable geometry that will not cause problems down the line. Here’s the PDF I’m importing if you’d like to take a look…Strat - full size.pdf(58.0 KB)

(Pascal Golay) #6

First thing to check is, on the existing solid where the existing fillet at the angled cut crosses/meets the vertical side walls- these edges are not correctly trimmed and joined.



OK, thanks, but even when I first extruded the profile curve I was having the same issue. Something must be wrong with the original profile curve that I’m importing from PDF? Is there any standard procedure when importing to make sure all the curves are workable? Here’s a file of the profile extruded but unable to be filleted…New Strat Extruded2.3dm(956.2 KB)

(Pascal Golay) #8

Yep, the other thing to look at are the vertical fillets at the neck area - these are maybe .25 inch radius and the .5 fillet cannot wrap around that. I’d leave that out - make the corners square and add this small filleting after the large one- generally the only useful strategy when mixing fillet radii at a corner- big first, wrap the smaller on on that. I’ll make an example here and see how it works.



OK, sounds good! The fillet goes all the way around till it gets to the neck pocket on top (the edges of the pocket itself don’t get radiused at all) and if you look at the PDF I uploaded, page 2 shows where to stop the fillets on the back. I had used this same PDF to draw up a previous model and didn’t have this issue. I was able to do the fillet on the back and blend from the .5 to 0 where the neck joins the body… That’s why this is so frustrating. I have made a completely workable model off of this very same PDF, but am rebuilding it now because I thought my technique had improved, HA!.. Thank you for the help though. Very much appreciated.


The problem with your curves is that they are joined beziers. That would be OK if
the bezier segments were all tangent but they are not (use curvaturegraph to see).

The best way to do this to avoid problems is to refit the curves as a simple spline. The main problem is going to be getting the fillet to go around the sharp corner of the horns. The easiest way to avoid problems there is to use true arcs in those sharp corners. Enclosed is a file that will extrude and fillet without a lot of fuss.
stratX.3dm(74.5 KB)


Hey Jim, thanks for the response!

Not really understanding about the curves. Is there a command to take a group of curves and make them tangent to each other? The profile curve imports as one open curve, but explode reveals that it is made up of 40 segments. How are these segments able to join if they are not tangent? I see what you mean with curvaturegraph. Looks messy. I get that when I draw a curve I want to use as few control points as possible to define the shape, but how can I clean up this profile curve without actually changing the shape? I haven’t worked with splines yet, but understand that they are perfectly smooth surfaces?

Thanks for the file, but how come the edges around the neck are now square? It looks the same to my eyes, but has the shape changed significantly elsewhere as a result of cleaning up the original curve?

Thanks again yall,


Hi Justin,
Pascal already explained the sharp corners. You can’t wrap a .5 fillet around a smaller fillet. You need to make the corners sharp to start and then add the smaller fillet after the larger one…

The command to convert to a spline curve is FitCrv or Rebuild. I usually use both first rebuild the curve to a high point count (say 100) then Fair the curve then refit to the desired tolerance. That usually gives a simpler curve than just using FitCrv directly.

The enclosed file shows the 3 steps involved in making the curve.

StratCurveX.3dm(45.1 KB)