Quick 3d modeling tutorial, Rhino

[GooCart]

Hi, there have been some discussion going on regarding 3d and CNC machines lately. I thought it could be interesting for you to see how you can model a guitar in a nurbs based software. It would be great if there are any polygon modeler out there who could share a polygon modeling tutorial so we can see both methods.

I'm keeping this very basic and I won't get in to deep in detail.

First you need some kind of sketch.

Place it as a background bitmap in Rhino and trace the contour.

Extrude the curve, in this case 45 mm.

Model the neck plane, here 3,19º.

Model the neck profile.

Extrude a box, here 1,5"

Cut the box with the body and keep the intersection.

Cut the neck to make room for the transition curves.

Build the surface.

And close it.

Cut the body with the neck to create the tenon cavity.

 

[GooCart]

Let’s focus on the headstock.

First, draw the thickness and angle.

Extrude the curves and draw the headstock design. I used the Bartlett International in this example.

Extrude the contour.

Trim and close.

Cut the surfaces to make room for the transition curves.

Build the first surface.

Draw the lines for the second surface.

Build and trim the second surface.

Back to the body,
here I used a 4,7 mm radius around the perimeter that decrease to zero at the neck joint.

Position the hardware.

Trim the cavities.

Well, that's about it. Design and modeling, approx 20 minutes. Time spent to post the thread, 2 hours........

 

[Gothika777]

You make it look easy. The background template idea makes things alot simpler but I take it u need a large scanner.

I've got a trial version of Rhino, so what I'll do is I'll put the catto plan as a back ground image and try and make a 3D les paul junior body model as my first task. Rhino looks alot easier to use than blender, maybe as Rhino looks more like autocad to me.

 

[GooCart]

This sketch was not much bigger than a business card, so the scanner size is no problem. That's how I work initial in the design process, a quick sketch on a piece of paper, just some guide lines so I have a clue what I'm aiming at and then I refine the design in Rhino.

But if you've traced the contours of a guitar in scale 1:1 you can assemble the scans in Photoshop.
There's a number of ways of doing inverse engineering. I've laser scanned guitars a couple of times but I'm not convinced that it's the best method. What I've found to be very useful is a Microscribe digitizer, a hand held contact-based device. It let me get the points I want, where I want them. A digital caliber and some kind of digital level might come handy also.

 

[Gothika777]

I've had a little go at doing something in Rhino.

I am not sure how to set the height of the extruding planar curve but I traced the catto plan anyway

 

[Ole'Lefty]

That is just great, Magnus-now I suppose you will have to kill all of us!!! (A common Yankee joke about our intelligence community)O'L

 

[ExNihilo]

NURBS ROCK!

That's fantastic Magnus! Really nicely done. Makes me want to try Rhino again. I haven't looked at it since 1999 or something. My biggest handicap in 3d is wanting my models to be a completely connected mesh. (I guess becuse I have done a bunch of organic modeling for animation). Your approach is very clean. I remember when I had a look at your top carve model that it seemed like you had a similar approach and I thought, "I wish I could do that!" Do you know what I mean? It's like tying your shoe a certain way. When someone else shows you how to do it much better, you are still stuck by habit doing it your own way. Anyway, this forum is just getting better and better. Guitars and 3d! Thanks!

 

[duff]

I've had a little go at doing something in Rhino.

I am not sure how to set the height of the extruding planar curve but I traced the catto plan anyway

type in the number of the amount u want it to extrude.

extudecrv --> select curve, press enter -->type number e.g. 40 -->hold shift to extrude it at a straight angle --> press mouse button 1. there u go..

then cap, select the surface and u closed it.

 

[duff]

NURBS ROCK!

That's fantastic Magnus! Really nicely done. Makes me want to try Rhino again. I haven't looked at it since 1999 or something. My biggest handicap in 3d is wanting my models to be a completely connected mesh. (I guess becuse I have done a bunch of organic modeling for animation).

I have the exact same problem with rhino, always trying to make the thing one big surface, because that's what gives best results when boxmodeling. Sometimes it's very frustrating because it doesn't always work in rhino (for me!)

Here's some really old work, guess it's 2004, not sure. Dont mind the stupid camerawork, i needed to show of the whole model if i can remember. Texturing wasn't finished, anyways, don't want to hijack the thread.

Thanks for this post Magnus

 

[Gothika777]

I tried do solid>difference with a square pickup in the body and it said boolean difference failed, any ideas? It worked when I did the pickup selector cavity.

Lol u can see I haven't quite got the hang of making nice smooth curves

 

[GooCart]

I'm glad you like the small tutorial, or demo might be a better word for it.
If anybody have the time and feel for it, please complete the thread with some guitar polygon modeling so we can see the different methods.

Finally I have to ad some renderings of the guitar, as usual rendered in Cinema 4D. It's kind of like a Status bass goes Vintage or something....

Say hey to the little guy down in the left corner, that's my new signature.

 

[GooCart]

I tried do solid>difference with a square pickup in the body and it said boolean difference failed, any ideas? It worked when I did the pickup selector cavity.

Lol u can see I haven't quite got the hang of making nice smooth curves

Rhino kind of suck if you try to make a boolean operation if the solids are flush. If you scale the cavity cutting solid in Z so that it is over the top surface it should work.

I'd try to look at the contour curve again if I was you. You have way to many points in it. Try to draw it with as few points as possible. You should be able to draw the complete perimeter except for the horn and cutaway with 12-16 points.

 

[Gothika777]

Your probably right, too many points will just make it jagged. I tried making the cavity part above the body but it sill doesnt work.

 

[ihavenofish]

great tutorial. neat looking guitar too.

rhino (and many other non engineering packages) have a floating accuracy, so planes that you think are exactly on top of each other usually arent, and cause things like that boolean failing.

and i agree about the edges. my LP shape in solidworks has maybe 20 points total including the horn. i traced mine over the catto pdf drawing and then altered the shape to be more like a modern LP.

its doesnt actually matter for cutting it out be it manually or cnc, but it makes it alot easier to manage if you wanted to tweak the shape or make other revisions. when you send it to a cnc mill, splines get turned into thousands of little straight lines about .005" long or less. (circular arcs are different).

 

[ihavenofish]

Your probably right, too many points will just make it jagged. I tried making the cavity part above the body but it sill doesnt work.

hm. perhaps its not a properly closed shape.

 

[Gothika777]

I thought that could be the problem but I don't think it is.

The solid was made by extruding this curve using solid>extrude planar curve so it must be a complete solid right?

 

[GooCart]

It doesn't have to be a closed solid just because you extrude it. Check the analyze toolbox/show edges and you'll see the naked edge highlighted.

 

[Gothika777]

How I get rid of naked edges?

I found the naked edges on the guitar shape but am unable to join them as there are no overlapping intergral. What I do?

 

[decoy205]

wow this is cool!

 

[Gothika777]

I've radiused the edges but they don't show when I render as the non radiused model is superimposed upon it. Its probably a simple thing but how do I change this?