Official Luthiers Forum!

The latest tsplines plug-in update, version 3.4 seems to be working well for modeling carved tops. The result was really good surface quality in a lot less time than using the built-in Rhino surfaces. Tsplines surfaces made with the tsskin command are not dependant on the point count, placement and alignment of the geometry that can make Rhino surfaces very complex and difficult to work with. This was a LP DC JR body shape made with some profiles and cross sections. The surface is simple enough that it can be edited to add more features by playing with points or their equivalent to isocurves. Lots of different ways to use it.

Not really pitching tsplines, since they were purchased by Autodesk which is not my favorite company. It can save a lot of time for carved tops.

The workflow is pretty straightforward. Let me know if you want more info on that.

We have Rhino T-Splines 3..... and for the price is a good product.

Have you looked at VSR or Clayoo? We think VSR is probably a better product for instrument building but we don't like the price, we don't think it's competitive with competition.

Blessings,

Kevin

Kevin have you tested Clayoo?

Mike

Kevin - I've watched some of the VSR videos but have not downloaded the trial. In the videos they show tough blends and matches with nurbs surfaces that tsplines doesn't really do. Why do you feel that it is a better product for instrument building ? The price is hard to justify unless it is the genuine golden hammer.

Does clayoo support mechanical precision as well as blob modeling ? I haven't looked at it.

http://www.clayoo.com/page/clayoo

Rand, it is a subd modeler for Rhino, but I am thinking, because of it sitting inside Rhino, the precision of Rhino would still be available.

I am one of those that think I need it, but that golden hammer thing keeps jumping out to scare me from time to time!

Mike

Clayoo is a product that I think is up and coming..... the drawback right now is the developer speaks Spanish and his English is a little hard to understand. He does listen to suggestions which is good.... problem we had was moving between the programs, but I think the developer will work this out. This program is more of a free flow modeling sculpting program that works with-in Rhino.

VSR is transparent you don't have to convert in and out within Rhino as you do with T-Splines it also allows more movement/manipulation of nodes as groups etc. We thought that it was much easier to shape objects than with T-splines and more intuitive........... but at the price! Don't get me wrong T-splines is not a bad program ...... like you guys I felt abandoned when Autocad purchased the company.... just waiting for the hammer to fall, and we have 4 copies.

Haven't purchased either Clayoo or VSR but have played with both programs for several hours..... liked VSR a lot but price.....

Blessings,

Kevin

Thanks Kevin, VSR does sound more useful especially if there isn't the one-way conversion. I see they have a webinar tomorrow so I'll take a listen.

Mike, I'm not sure my propeller head likes the whole sub-d thing. I think I need the Jedi mind meld. Or the Vulcan mind meld. whatever

What's that old proverb: better the master of one tool than the collector of many ?

Not sure if you saw, but i got an email from the founder of Tsplines and they have resumed development for Tsplines for Rhino.

I'm late to the party on this thread, but to the OP, I'd love to know a little more about the workflow in creating a carve like that with T-splines. I'm struggling with something similar in Rhino, without using plug-ins.

Tspline carve top workflow

Start with clean low point count body profile since it will be used to trim the tspline to size.
• Construct overbuild profile to accommodate horns from a copy of the body profile
• Construct center profile (flat) and side elevation profile. Crv2views to create a 3d center profile.
• Construct cross sections (blendcrv G2) between the 3d center and overbuild profile. Draw colinear cross section lines across center section so that the surface structure will be the similar between the center and outer.
• tsskin the center profile, elevation profile and center cross sections. Set spans on center profile: bottom:3 middle:3 top:1
• tsskin the outer ring to the center profile and cross sections. Spans on overbuild segments must match those of the center profile so the surfaces will match. Cross sections each get 2 (or 3) spans.
• tsmerge the inner edge of the outer ring to the outer edge of the center section to make it once tspline surface
• Using the tspline HUD double click select the entire outside edge (sides not top). Make sure tsplines gumball is positioned approximately at the center of the waist. If not use the set pivot button to reposition. Push the scale button and double click the axis square of the gumball to bring up the scale command line prompt. Scale the outer edge by approximately 1.03 so that the surface is extended outside of the body profile.
• Make any point or edge editing to the tspline before the next step.
• Trim a copy of the the tspline surface to the body profile. This changes the tspline into a nurbs polysurface which cannot be edited.

I can't seem to upload a zip or .3dm file but just PM me etc and I'll send it.

With this geometry layout you can get close using Rhino's builtin surfaces however since commands like sweep2 are very sensitive to the point structure (count and having them aligned properly) you can get icky stuff. Let me know where you get stuck and I'll help. RAK

I'm still a bit confused about where the advantage is. The curves shown above will generate a fine surface using the standard Rhino surfacing commands (Sweep2, rebuildcrv, interpcrv, matchcrv). Is it that TSplines builds the curves for you with proper tangency and handles the rebuilds?

Has anyone made a tutorial on doing a carvetop (video) with TSplines? Maybe that'd make it a bit clearer for me.

_________________
Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

Good question. For a long time I just used the builtin Rhino surfaces, mainly because that worked ok and the earlier Tsplines versions didn't work the way I wanted. Tsplines doesn't care about the underlying point structure of the curves, it uses its own spans control to determine surface complexity (like isocurve but different). A single Tspline surface always has G2 continuity. In the workflow I've outlined I make two surfaces and merge them which become one single G2 continuous surface with no fuss.

For carved tops a Tspline surface can be made with the traditional 3d wireframe geometry I've shown or you can make a flat surface with a similar layout and then select their internal edges (or points) and shape by raising and lowering the elevation. Combining both, getting a pretty good surface via wireframe and then tweaking is very powerful. In Rhino the surfaces are too complex to edit and you just iterate on the geometry until it makes the right shape.

Never made a video. Give me a point in the right direction and maybe I can make something to show how quick and easy it goes.

I have no real idea if your surface arching is good or not. I would need a 3D to tell for sure. From the above rendering it looks very good though. If it is not proprietary, send me a 3D at Kenmckay_at_hotmail.com and I will look it over in Rhino.

_________________
Ken

Rand,
I looked at the Rhino you sent. The arching looks good for that guitar imo. I think the t splines do a good job for this style.

_________________
Ken

Yeah, it sounds like what I was thinking. It's adding in a bit of the joy of parametric surfaces to Rhino, particularly the automatic rebuilds.

(Workflow commands are in bold and options in those commands are in italics)

What T-splines is doing for you is drawing up the proper start tangent and end tangent lines for interpcrv or as input for blendcrv, and making sure the curves have the same number and spacing of control points (like rebuild). Then it's using sweep2 or networksrf for surfacing and making sure to cut the input up properly. The great 'tweaking' bonus is that if you fiddle with your input, it redoes all the steps for you without you doing anything.

Everybody is stuck with the idiosyncrasies of NURBS, so underneath it's all the same stuff. The trick is keeping the user away from them (which it looks like they do a good job at). How does T-splines do with surfacing objects with soft and hard edges, like the transition areas on an acoustic neck where it comes to the headstock or the heel/body? I'd say that those are the hardest surfacing problems to be found in guitar construction, or at least they were the last ones I really nailed when I was learning.

_________________
Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

Tsplines is some kind of variant of nurbs. You can convert a nurbs surface (not polysurface) to a tspline and you can explicitly convert a tspline to nurbs and that happens when you do things like trim. The conversion to nurbs is generally destructive (undo works). Tsplines also has features of subdivision surface modelers but not polygonal. You can start with any of the solids primatives and extrude faces and manipulate as desired to make much more complex shapes. You can keep adding complexity to parts of a surface by adding points, subdividing existing faces etc and the basic shape is retained until you manipulate the new features. They have hard creases so for example you can take a carved top surface add a crease and extrude down to make the whole body as one single creased surface. If you've got a few minutes I'm sure there is an overview tsplines video on their website/youtube as I'm not doing a very thorough job of explaining what can be done.

One of the nice things about Solidworks surfacing is the way it hides complexity behind the curtains.

I haven't used tsplines for the tough neck areas. I create the geometry I want and use sweep2 or networksrf. I do not use tsplines as a kind of universal or super surface for tough areas and I don't think they have all the features for that. Somebody that is proficient with it could make an entire neck as a single tspline surface. I'm not sure what that would be good for though.

Bob,

Have you done any research into tSplines? there are some fundamental differences between conventional NURBS surfaces and a tSplines surface.

http://cagd.cs.byu.edu/~tspline/innovat ... spline.pdf

http://cagd.cs.byu.edu/~tspline/innovat ... pline2.pdf

tSplines works very well creating transitions

http://www.youtube.com/watch?v=IXkw-2hn7bo

_________________
www.morganguitarworks.com
www.morgancustomguitars.com

I never realized there were academic papers on them, thanks for pointing me to those.

The first paper was pretty good, and shows some really good uses of T-splines for matching surfaces. Transitions are really where their strengths lie. They become a need when the NURBS surfaces have problems to begin with (poorly aligned patches) but that does expose the need for the user to pre-empt those issues in NURBS where in T-splines the software can take care of it.

The second paper was, to be frank, disingenuous and deceptive. They use strawman examples of NURBS surfaces which haven't been optimized at all, then tout the amazing results they got in conversion. 90% or more of their 'improvement' would have been covered by a basic NURBS surface optimization / rebuild. I have to question whether the researchers were being deceptive on purpose or whether they just didn't understand what they were doing. If you look at Figure 3, the loss of fidelity and even whole features is plain as day in the T-splines model. The whole bottom of the nose disappeared, nearly all detail was taken away from the neck and both lips...and that's visible in a thumbnail sized image.

The video really shows the power of the software. I wonder a bit how much of it is the actual T-splines and how much of it is good tools programming. Sometimes I'd really like to be able to dig into peoples trade secrets . Regardless of what's going on behind the curtain, I don't think there's any question that the ability to just whip out a complex transition as shown in that video doesn't really exist in the standard offerings. You can do it, but you need to have prepared every prior step just right for it to work and that's a hassle. It'd be a great business move for McNeel or Dassault to buy out that company and integrate that tech into their standard offering.

_________________
Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

Too late: Autodesk Acquires T-Splines Modeling Technology Assets

_________________
http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

Well, at least Inventor will finally have something going for it

_________________
Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services