[kbeard]

Hey there!

I'm about 2/3 finished building my CNC machine. It certainly looks homemade! I just hope it works!

I'm working on a copy of a 1947 D'Angelico "New Yorker" archtop guitar.

Well, I'll admit it! I am stumped! I have tried to get the attached AutoCad DXF file to surface correctly but nothing works. I've also tried to surface the guitar in Bob-Cad. Nothing! Surfaces just go nuts.

Can someone help? I'm at my wits end...

P.S. The gaps in the splines at the bottom of the guitar are there for a reason. The surfaces that I was trying to create seemed to need good start points and end points. I can close them back up if that would help...

Kevin...

[Jimb3893]

Hi Kevin. I was able to create a surface using a drape method. How can I send you the file, and what format do you need?

Jim

[ger21]

Are you trying to surface it in AutoCAD? If so, are you lofting or using meshes.

First, the outer two profiles are drawn in the opposite direction to the rest. They all need to be in the same direction. And if lofting, you'll need to add a bunch of guide curves. I quickly drew a few and got it to loft by leaving out the outer two contours.

Fwiw, this is probably one of the most difficult things to do in AutoCAD. Rhino would probably be a better option.

[Montabelli]

I don't know if your soft ware will do it but I have found it is better to separate the surface from the outline shape and then project the tool path onto the surface once you get it where you want it. In mastercam I create a lofted surface that extends well beyond the instrument outline then create a 2d tool path that goes where I want it to, usually a pocket, then project that pocket onto the surface adding depths.

The reason for this is that in my experience it is easier to create the surface and get it smooth and flowing by making it square or at least not confining it to the boundary of the instrument. some times you can influence where the surface goes inside the instrument boundary from outside.

Also make sure that the software you use is capable of making smooth curves and surfaces, other wise it will all be up to your finger plane.

[kbeard]

Thanks for all of the responses!

The original splines are drawn in AutoCAD. I've tried to loft the surface in AutoCAD and to cross-section in Bob-Cad. Nothing working yet.

Jim...

What in the world is a "Drape" command? Which software?
The software that I have available is AutoCAD, Alibre, ProgeCAD, and BOB-Cad.
(You can probably tell that I'm definitely a low-budget kind of guy)

I'm going to need to get the surface into Bob-Cad which will read IGES, DXF, Rhino, SolidWorks, and STEP files.

Kevin...

[chris tynan]

Hi the surface you require in BobCad, I have surfaced the design by joining the gaps at the base also make sure there are no duplicate lines.
I use version 23

[Jimb3893]

Kevin: I can email an iges file if you like. I'll just need to get your address.

Or can I post it to this page? How?

Jim

[ger21]

.zip it

[kbeard]

Thanks again for sending the surface file.
Did it take a long time to create the surface in your software?
I wish there was a method to make the surface in AutoCAD, ProgeCAD, or Bob-Cad.

Here are some instructions for attaching a file to your post.

At the top of the page, click on "Post Reply". Don't use anything other method of posting. They won't allow you to attach a file.

a) Click on "Reply to Thread".
b) Give your message a title.
c) Write Your message
d) A bit lower on the page you'll see "Additional Options", "Attach Files", and "Manage Attachments".
You can only attach the following types of CAD files: dwg, dxf, png
The best way to send any other type of file you will need to first create a "Zip" file and attach the zip file to the post.

e) You can then post the message along with the attachment.

Hope this helps...

[Jimb3893]

Actually Kevin it's pretty quick and simple in Visi. Select "Drape Surface", window select the curve geometry, and, voila!

I hope it works for you.

Jim

[kbeard]

Jim, You still out there?

I made a mistake on the previous topographic. The splines that I sent to you were an approximation. Could you possibly create the surface one more time? I've corrected the splines to more accurately reflect the curvature of the guitar.

Any help would be appreciated!

Thanks...

Kevin

[Arch]

I made splines using the curtate cycloid in Rhino and then just use the patch for the surface. I saved in several different formats hope this will help. Curtate cycloid is supposedly the method for arching patterns that Stradavari used when arching his violins. I use them on archtops and they look great.

[kbeard]

That worked out perfect! Thank you for the help. I'll have to take a look at those curtate cyloid thingy's. Rhino rocks!

My son and I are just about finished with the home-made CNC machine. Can't wait to start working on the '47 D'Angelico New Yorker.

Thanks again!

[Arch]

My son and I have designed some really cool archtops in Rhino. I've cut some tops and backs on my K2 router and the consistency is really a lot better than hand carved. When you get the hang of arching in Rhino the possibilities are awesome. And we designed and cut him one heck of a soap box derby racer.

[Arch]

Kevin, I may have changed the outer dimensions from your plan in doing this. Make sure you resize it accordingly.
Randy

[Matt Clara]

I made splines using the curtate cycloid in Rhino and then just use the patch for the surface. I saved in several different formats hope this will help. Curtate cycloid is supposedly the method for arching patterns that Stradavari used when arching his violins. I use them on archtops and they look great.

I can't find much on curtate cycloid in Rhino--can you tell me more (I have Rhino 4)?
Thanks.

[ger21]

I think they're talking about this.
http://www.cgl.uwaterloo.ca/~smann/ccycloid/

[Matt Clara]

I think they're talking about this.
http://www.cgl.uwaterloo.ca/~smann/ccycloid/

Thanks Gerry. I'm just going to PM all my questions to you from now on...