Help with instrument neck surfacing issues?

Rhino Rhino for Windows
1

Hello everybody, I’m completely new to Rhino (and really CAD in general) as of this week, so I apologize ahead of time for the numerous issues there likely are with my approach to design here. I’m attempting to create a banjo neck and I was very loosely following the methods applied in a Rhino guitar neck video I found on YouTube by Helix Guitars (https://www.youtube.com/watch?v=wLaPAeKPuqA&t=2016s). I never could get the network surfacing he was demonstrating to work, so most of the surfaces are patch surfaces or surfaces from 3 to 4 curves.

This first picture shows the basic design (ignore the weird horn shape at the end as it’s supposed to be a step in the process towards making the neck volute transition). The arrows are just showing where I placed neck profile curve drawings to define the neck shape.

Banjo Neck
Banjo Neck1591×741 138 KB

This is the side of the heel transition and it’s dipping inward from the neck profile. I’m trying to figure out a way set a limit somehow, where it cannot dip below/inward from where the neck profile would have been if it continued through the heel.

Heel dip
Heel dip968×758 48.6 KB

This next picture is the top of the neck’s heel portion, showing this weird peeling effect I’m getting, where the patch surfaces don’t exactly line up with my curve drawing, and hence, not with each other either. I’ve tried showing object control points and tweaking them, but it’s always an unsatisfactory compromise, not following the original profile drawing directly.

Peeling patches
Peeling patches828×720 22.9 KB

The final picture here is showing another way in which the surfaces are just not following the profile curves I drew, and how they misalign unless they’re continuous. Even if I could make these continuous though, it’s concerning that they’re not directly following the profiles I’ve drawn.

Profile misalignment
Profile misalignment940×561 47.9 KB

I would greatly appreciate any help you all can provide. I’m trying to design CAD models to machine from hardwoods on a new CNC router I’m having made. I really want the designs to be exacting to avoid needing to correct any geometry by hand after the fact. There’s a ton to learn with Rhino, but I’m hoping I can figure this craziness out! Thanks for your time in reading this.

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@sgreenawalt has made a series on YouTube about clean surfacing. I’d recommend watching that first as your current approach will never get you satisfactory results.
Patch and NetworkSrf should only be used in very rare cases and certainly not for your primary surfaces.
Other than that, have you followed a level 1 training or went through level 1 training guide already? This contains a lot of essential basic information you need to know.

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Thanks for your reply! I just found his series on YouTube. I’ll start going through that tomorrow. Much appreciated! Concerning training, I just watched a few video tutorials on YouTube. Where would I find official Level 1 training?

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Level 1 training is given by McNeel and resellers both online as well as on site. But you can also learn a lot by self paced training, reading through Level 1 training manual and doing the exercises. The manual you can find in Rhino —> Help —> tutorials and samples

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Thanks for the heads up about Level 1 training. I’ll definitely read through it or find an online training. Appreciate the help and have a great week!