T-Splines
T-Splines

Current version

Download the current version.

Autodesk T-Splines Plug-in for Rhino v3.4 Download
Autodesk tsElements v1.2 Download

Featured threads

The links below lead to some of our favorite forum threads.

052775 052099

29164 052640

29164 29164

052346 052775


See more featured threads.

Webinars

Date Topics  
7/09 Creating stunning jewelry designs with T-Splines View
5/07 How to approach modeling with T-Splines View
3/07 Carl Bass reintroduces T-Splines for Rhino View
6/21 Transitioning from NURBS to T-Splines View
12/07 Footwear modeling with T-Splines 3.3 for Rhino View
11/29 New T-Splines reverse engineering tools View
10/28 How T-Splines changed my aproach to making jewelry in CAD View
09/29 Modeling a water gun View
09/07 Car modeling:
Parts 1, 2, & 3
View
07/06 tsElements intro
hosted by Novedge
View
06/22 Free-form Architecture View
06/15 TS Pipe command View
06/08 T-Splines for Rhino intro View

L-39 Custom Wingtips

A support and feedback forum for Autodesk T-Splines Plug-in for Rhino users.

L-39 Custom Wingtips

Postby sgreenawalt » Wed Feb 23, 2011 4:32 pm

I've been working on a project for a customer who services L-39 jets, and has one that races at Reno. He created some custom wingtips, and now wants to sell sets of them. However, he has been hand shaping them, and it takes him the better part of a month to make a set. So I went over with my trusty FARO arm, scanned the tip, and then modeled it in T-Splines. Tomorrow I'm going to print out some full size templates to compare my model with the actual pieces, and then I'll move on to machining the molds on a 3-axis mill. This is the first project where I have been able to intuitively understand the T-Splines topology, and have been able to really know what direction I was heading, before I got there. I can say that I absolutely saved time over doing this in NURBS, and the fact that unified topology allows me to make subtle modifications to my model (say, if I need to tweak the airfoil shape where it mates to the wing) is just completely transformative over how I used to work. I'm never going back to NURBS.....

If all goes well tomorrow, I'll probably be cutting molds on Friday. Fingers crossed.

-Sky
Attachments
WingtipRender5.jpg
WingtipRender4.jpg
P1000158.JPG
P1000161.JPG
sgreenawalt
Poster
 
Posts: 125
Joined: Wed Feb 11, 2009 10:18 pm
Location: Santa Cruz, CA

Re: L-39 Custom Wingtips

Postby JSantocono » Thu Feb 24, 2011 6:24 pm

Cool project Sky!

Thanks for sharing.
JuanS
User avatar
JSantocono
Poster
 
Posts: 795
Joined: Thu Jan 03, 2008 10:18 am
Location: Argentina

Re: L-39 Custom Wingtips

Postby sgreenawalt » Tue Mar 01, 2011 8:18 pm

Thanks Juan!

Closing in on cutting the molds for this. I went over to test my work against the existing aircraft, which was a good thing, because when I got there the customer explained that the wing the tips would be going on was slightly different than the one I scanned! :shock: I took some measurements, made some modifications and now I'm tantalizingly close to cutting molds on this one. The silver surface in the current rendering is for the tip light lenses. Those have been the absolute bane of my existence - since the molds for those were hand carved, getting the "ideal" tip surface to nicely mesh with what is a very "analog" surface requires quite a bit of work.

-Sky
Attachments
WingtipRender6.jpg
sgreenawalt
Poster
 
Posts: 125
Joined: Wed Feb 11, 2009 10:18 pm
Location: Santa Cruz, CA

Re: L-39 Custom Wingtips

Postby Adam Helps » Wed Mar 02, 2011 11:45 pm

Yeah, hand-carved surfaces probably don't come out as simple polynomial functions, the way NURBS and T-Splines do ;). That sounds like a pain -- I guess you'd just load in some scanned curves and try to fit to them?

Anyway, this is a really cool project, we've enjoyed following it :).
User avatar
Adam Helps
Employee
 
Posts: 555
Joined: Thu May 26, 2005 2:15 pm
Location: Provo, Utah

Re: L-39 Custom Wingtips

Postby sgreenawalt » Fri Mar 04, 2011 3:16 pm

Thanks Adam! When you're asking about loading some scanned curves - are you asking about how I created the wing surface in Rhino? Just not sure what you're asking.

-Sky
sgreenawalt
Poster
 
Posts: 125
Joined: Wed Feb 11, 2009 10:18 pm
Location: Santa Cruz, CA

Re: L-39 Custom Wingtips

Postby Adam Helps » Fri Mar 04, 2011 5:16 pm

Yeah, I was wondering how you managed to build the curves for the lights, since they're not exactly CAD data. I was guessing you could scan the shape, or import a photograph, or something of that sort. Or just lots of guess-and-check, perhaps? :P
User avatar
Adam Helps
Employee
 
Posts: 555
Joined: Thu May 26, 2005 2:15 pm
Location: Provo, Utah

Re: L-39 Custom Wingtips

Postby sgreenawalt » Sun Mar 06, 2011 12:16 pm

Adam -

Well I suppose you're in luck, because I'm about to redo them! The original ones were built using points digitized with the FARO arm. If you look at the pictures, you can see there is a black "ring" around the tip lenses. I scanned the outer edge of the lenses, getting maybe 15 points or so, and then scanned roughly the same number of points along the inside of the "ring", which is about 1" inside of the exterior curve. Then I created a interpcrv through the points, rebuilt those with the same number of points, and then lofted to get the resultant surface. Since the digitizing arm uses a 0.25" ball probe, the surface is .125" offset in the normal direction, towards the inside in this case. Rather than trim my T-Spline and match it to the lens, I opted instead to tweak the points on my surface model until they just "kissed" the light ring. Now, after all that, the customer has decided to use a different tip light, which is longer. The lenses were made oversize and then trimmed, so now I'm going to scan the "raw" lenses so that I can get a really accurate match with a larger lens. If folks are interested I could post a sort of step by step.

-Sky
sgreenawalt
Poster
 
Posts: 125
Joined: Wed Feb 11, 2009 10:18 pm
Location: Santa Cruz, CA

Re: L-39 Custom Wingtips

Postby JSantocono » Tue Mar 08, 2011 11:13 am

Hi Sky,
We dont want you to show the steps since it seems that the project itself is a lot of work :-) , and adding a steps screenshot to your workflow would only add more work for you....
But we are enjoying this project so any stuff you can post would be cool for us and other users I guess...
Your workflow looks very pro indeed. You are the man!
Thanks for sharing!
JuanS
User avatar
JSantocono
Poster
 
Posts: 795
Joined: Thu Jan 03, 2008 10:18 am
Location: Argentina

Cutting has begun!

Postby sgreenawalt » Wed Mar 09, 2011 7:40 pm

Hey Juan -

Actually, as I told Matt last week, I'm going to be starting a blog in a few weeks that will go really in depth on all aspects of my production - I found that I've got so much software and hardware stuff going on at this point, it makes more sense to put it all in one place.

Anyhow - it took me far longer than I thought to break the molds up and create the g-code, but I am indeed now cutting! I've got the first set of molds running on the CNC right now, should be done in about another 6 hours or so. This is my first time cutting with high density (25 lb) polyurethane foam - it doesn't cut quite as fast as the Dow "surfboard foam" I normally use, but it's very nice and much more durable.

I took a quick snapshot of the mil in progress, I didn't want to hang around too long with my nice new camera, since the dust is pretty intense. Attached is also a screenshot of the mold being milled. It's the top halves of the main "shells" of the wingtips - both the left and right in one mold. There's also a few screenshots of what goes into prepping the surfaces for tooling - the parting lines need to be defined, and since these parts must overlap and be bonded together, even the thickness of the carbon needs to be accounted for. The "channel" running between the top and bottom halves is for 2 layers of carbon that will cover over the seam, once the halves have been bonded together. I'll post more later (including some screen shots on digitzing the wingtip lenses, and how the V3 symmetry function totally and completely saved my bacon!) but right now it's dinner time and I'm beat!

-Sky
Attachments
TopBottom_Detail2.jpg
TopBottom_Detail.jpg
TopHalves_Tooling.jpg
P1000631.JPG
sgreenawalt
Poster
 
Posts: 125
Joined: Wed Feb 11, 2009 10:18 pm
Location: Santa Cruz, CA

Re: L-39 Custom Wingtips

Postby sgreenawalt » Thu Mar 10, 2011 10:44 am

Adam -

Here's a bit of info on how I dealt with the wingtip lenses. Let me start by saying that it would be much smarter/better/easier to just design the lenses in TSplines, and then machine molds, but in this case the customer had invested quite a bit of time and money in making the wingtip lens molds (and many sets of production parts) before I came along, and so it was important to him that we keep that existing work. Since the customer is always right, I had to find a way to make the existing parts work on the "new" wingtips.

I started by digitizing the lenses with my FARO arm. There is a definite art to this, and I feel I'm getting there, but this is a whole other skill set that takes time and practice to develop. I've found that digitizing evenly spaced points on the surface results in the best and most accurate surface, so I actually plan out every point that I digitize ahead of time. Digitizing is about 75% prep and 25% actual work with the arm. I had to find a way to fixture the lenses without breaking them, so I used some chevant clay to hold them on a piece of shelf board. Masking tape was applied to the board so that the clay would stick better to it - I thought I had it all worked out the first time, and then the lenses just popped right off the board with the clay! In this particular case, there will be a flange around the edge of the lens that will attach it to the tip, and so that's the most crucial part. The actual lens surface itself isn't nearly as important as the flange around the perimeter. So, I laid out two concentric rings of points - one along the perimeter, and one about .75" inside of that - each with the same number of points. For the rest of the surface, I just made three cross sections in one direction, and one in the other. Then I rebuilt all my curves, which helps to take out some of the waviness, and I made all my cross section curves planar. Then you have to compensate for the radius of the ball tip on the digitizer - the digitizer captures the point at the center of the ball probe, and so you have to compensate for that - in this case since I used a .25" ball probe, everything had to be offset by .125" After that, I imported the lenses into my main file, and then placed them on the tips manually, just by moving them around until I felt they were as close to where the main surface was, and then tweaking my wingtip surface.

This was where the power of the new tsSymmetry command really shined - I was able to keep working on the back 75% of my model (since I was still making some final tweaks to the winglets) while matching both the left and right tips to their respective lenses. There were significant enough difference between the left and right tip to justify tweaking each side independently. The way I matched the tip to the lenses might sound like insanity to some, but what I did was simply manually tweak my tip surface until the meshes of the tip and the lens got all "mottled" with each other. I wanted to have the lenses exert the least amount of influence on my surface, and so this method, while seemingly backwards was a good work around for the situation. Like I said before, these lenses have been the hardest part of this project, but T-Splines made it much easier. I left myself with one last option for adjustment when I go to fabricate and assemble these - since the parting line between the top and bottom shell goes right through the lens, I can slide the top and bottom shells around a little before I join them together, using the actual lenses to ensure a perfect fit.

-Sky
Attachments
TipWithLens.jpg
After manually "matching" the tip to the lens, the meshes get all fuzzy and mottled when they match up.
LeftLens_withOffsetSrf.jpg
Blue inner objects are the offset version, which is the corrected shape.
LeftLens_OuterSurface_n_Curves.jpg
Lofted outer ring to make surface
LeftLens_Curves_n_Points.jpg
Points were digitized, and used as the basis for curves
P1000624.JPG
Lenses affixed to shelf board with clay
P1000626.JPG
Faro arm on stand, 200 lbs of salt keeps it nice and stable.
sgreenawalt
Poster
 
Posts: 125
Joined: Wed Feb 11, 2009 10:18 pm
Location: Santa Cruz, CA

Re: L-39 Custom Wingtips

Postby JSantocono » Thu Mar 10, 2011 11:22 am

Lol, great!
You know what you are doing! :wink:

BTW, nice kitchen setup. I bet my wife would kill me if I place that beautifull faro arm on his kitchen. :lol:

Interesting workflow,...leave something for the webinar! :-)

JuanS
User avatar
JSantocono
Poster
 
Posts: 795
Joined: Thu Jan 03, 2008 10:18 am
Location: Argentina

Re: L-39 Custom Wingtips

Postby sgreenawalt » Thu Mar 10, 2011 1:38 pm

Thanks Juan! Yeah my wife was a really good sport about that. She was also a good sport when some of the clay which I head heated up in the oven (it's very stiff when at room temp) managed to stay in the oven, and then the whole thing smelled awful. I had to pull all the racks out, clean them thoroughly, clean out the oven, and then leave it in self clean mode for an hour or so. That's the last time I'll ever do that - I'm going to get a little toaster oven for heating up the clay in the future.

-Sky

PS - I woke up feeling like it was Christmas morning today - drove down to the shop where we keep the mill, and was thrilled with how well the mold came out. I will post some pictures later.
sgreenawalt
Poster
 
Posts: 125
Joined: Wed Feb 11, 2009 10:18 pm
Location: Santa Cruz, CA

Re: L-39 Custom Wingtips

Postby sgreenawalt » Thu Mar 10, 2011 7:53 pm

Here's a few pics of the machined mold. There's a few very minor issues that I'm going to work on for future cuts, but I'm about 95% happy with it, and it's 100% usable, so I'd say that's pretty darn good.

-Sky
Attachments
P1000645.JPG
P1000643.JPG
P1000640.JPG
sgreenawalt
Poster
 
Posts: 125
Joined: Wed Feb 11, 2009 10:18 pm
Location: Santa Cruz, CA

Re: L-39 Custom Wingtips

Postby SDS » Fri Mar 11, 2011 9:01 am

Fantastic! It's a long road from a bare surface, to detail design, then to designing a part that can be made, then actually making it.
Is that RenShape 5025 material? Wonderful material.
SDS
Poster
 
Posts: 80
Joined: Sat Oct 31, 2009 1:38 pm

Re: L-39 Custom Wingtips

Postby sgreenawalt » Fri Mar 11, 2011 9:30 am

SDS -

Yes indeed, it is Renshape 5025. Quite pricey, but yes, very nice. I've got some more material on order for the rest of the molds - I'm going to try some 15 lb PU tooling foam and see how it compares. I had this billet of Renshape sitting around for the last nine months or so, and so I just decided to use it on this project.

It does take quite a long time to go from unified surface model to mold, but I'd much rather be doing this than grinding on some plug for hours on end. :D

-Sky
sgreenawalt
Poster
 
Posts: 125
Joined: Wed Feb 11, 2009 10:18 pm
Location: Santa Cruz, CA

Re: L-39 Custom Wingtips

Postby SDS » Sat Mar 12, 2011 6:23 am

Check the specifications- 5025 is 15 lb/ft3.
Keep up the good work and keep us posted on your progress.
SDS
Poster
 
Posts: 80
Joined: Sat Oct 31, 2009 1:38 pm

Re: L-39 Custom Wingtips

Postby sgreenawalt » Sat Mar 12, 2011 11:32 am

Oh indeed, you are right. I got two billets of 15 lb PU tooling board from RevChem yesterday, for roughly the same cost as what I paid for the single billet of RenShape. We'll see if there's any difference between the two. I'll be doing a layup in the first mold tomorrow, should be popping parts out on Monday. I'll post pics!

-Sky
sgreenawalt
Poster
 
Posts: 125
Joined: Wed Feb 11, 2009 10:18 pm
Location: Santa Cruz, CA

Re: L-39 Custom Wingtips

Postby sgreenawalt » Mon Mar 14, 2011 9:46 am

It's starting to get exciting - I always love it when I can lay my hands on the actual physical part of the computer model I've been working on. Got the first mold laid up yesterday, and popped the parts out this morning. They're looking very nice, very few blemishes on the parts I care about. Time to cut some more molds!

-Sky
Attachments
P1000656.JPG
Mmmmmmm.....carbon.
P1000649.JPG
The mold in the vacuum bag. Didn't have time to take any in progress photos but my friend did and I'm sure he'll send me some.
sgreenawalt
Poster
 
Posts: 125
Joined: Wed Feb 11, 2009 10:18 pm
Location: Santa Cruz, CA

Re: L-39 Custom Wingtips

Postby JSantocono » Mon Mar 14, 2011 9:59 am

Nice!! I love composite parts!
sgreenawalt wrote:I always love it when I can lay my hands on the actual physical part of the computer model I've been working on

Yea, me too. Is good to "get out" from virtual from time to time :-)
JuanS
User avatar
JSantocono
Poster
 
Posts: 795
Joined: Thu Jan 03, 2008 10:18 am
Location: Argentina

Re: L-39 Custom Wingtips

Postby sgreenawalt » Mon Mar 21, 2011 3:48 pm

Moving right along - I've designed the jig fixture to hold all the sub assemblies aligned while I join them. It will be made from 3/4" finish grade plywood, which will be CNC water jetted at the local metal fabrication shop. I have the bottom mold all machined, and now I'm machining the molds for the winglets. Getting closer...
Attachments
JigFixture.jpg
sgreenawalt
Poster
 
Posts: 125
Joined: Wed Feb 11, 2009 10:18 pm
Location: Santa Cruz, CA

Re: L-39 Custom Wingtips

Postby sgreenawalt » Fri Apr 01, 2011 5:07 pm

Getting very fun now! All the sub assemblies have been made, and for the first time I can fit them together in the jig fixture. I can't imagine doing this job in NURBS, or getting the quality of surface that I was able to get using T-Splines. Should have these all finished off by the end of next week!

-Sky
Attachments
P1000759.JPG
P1000757.JPG
P1000755.JPG
P1000754.JPG
P1000753.JPG
sgreenawalt
Poster
 
Posts: 125
Joined: Wed Feb 11, 2009 10:18 pm
Location: Santa Cruz, CA

Re: L-39 Custom Wingtips

Postby Chris Botha » Fri Apr 01, 2011 6:56 pm

Awesome project, thanks so much for sharing! Always nice to d\see other peoples workflow, always learn a little trick or two :)

regards
Chris
User avatar
Chris Botha
Poster
 
Posts: 375
Joined: Thu Mar 10, 2011 5:11 am

Re: L-39 Custom Wingtips

Postby sgreenawalt » Sat Apr 02, 2011 3:46 pm

Thanks Chris!
sgreenawalt
Poster
 
Posts: 125
Joined: Wed Feb 11, 2009 10:18 pm
Location: Santa Cruz, CA

Re: L-39 Custom Wingtips

Postby sgreenawalt » Tue Apr 19, 2011 5:00 pm

Well these are just about finished, should be delivering to the customer on Thursday. Can't wait to make another set, these have been really fun to work on - challenging at times, but that's when I learn the most.
Attachments
P1000954.JPG
P1000956.JPG
P1000958.JPG
sgreenawalt
Poster
 
Posts: 125
Joined: Wed Feb 11, 2009 10:18 pm
Location: Santa Cruz, CA

Re: L-39 Custom Wingtips

Postby JSantocono » Wed Apr 20, 2011 7:57 am

Hey Sky, the part looks awsome!
Thanks for sharing these pictures. There is only one pict left in order to complete the full story........a picture with the part on the plane on the air! :-)
JuanS
User avatar
JSantocono
Poster
 
Posts: 795
Joined: Thu Jan 03, 2008 10:18 am
Location: Argentina

Re: L-39 Custom Wingtips

Postby sgreenawalt » Mon Sep 12, 2011 6:55 pm

JSantocono wrote:Hey Sky, the part looks awsome!
Thanks for sharing these pictures. There is only one pict left in order to complete the full story........a picture with the part on the plane on the air! :-)
JuanS


Well it took a bit Juan, but here you go:

http://betterlivingthroughcnc.com/2011/ ... delivered/

-Sky
sgreenawalt
Poster
 
Posts: 125
Joined: Wed Feb 11, 2009 10:18 pm
Location: Santa Cruz, CA

Re: L-39 Custom Wingtips

Postby Matt Sederberg » Tue Sep 13, 2011 2:55 pm

sgreenawalt wrote:
JSantocono wrote:Hey Sky, the part looks awsome!
Thanks for sharing these pictures. There is only one pict left in order to complete the full story........a picture with the part on the plane on the air! :-)
JuanS


Well it took a bit Juan, but here you go:

http://betterlivingthroughcnc.com/2011/ ... delivered/

-Sky


Awesome!
User avatar
Matt Sederberg
Employee
 
Posts: 1484
Joined: Wed Jul 13, 2005 11:27 am
Location: Provo, UT

Re: L-39 Custom Wingtips

Postby SDS » Wed Sep 14, 2011 4:39 am

Congratulations- I know it's a really-really good feeling to finally see your creations fly away!
This makes me look forward to seeing your next product.
SDS
Poster
 
Posts: 80
Joined: Sat Oct 31, 2009 1:38 pm

Re: L-39 Custom Wingtips

Postby vincente » Thu Mar 28, 2013 12:39 am

sgreenawalt wrote:It's starting to get exciting - I always love it when I can lay my hands on the actual physical part of the computer model I've been working on. Got the first mold laid up yesterday, and popped the parts out this morning. They're looking very nice, very few blemishes on the parts I care about. Time to cut some more molds!

-Sky


Fantastic work! It is so nice to things built from cratch.
Just a little question, how did the carbon become the shape of a wigtip over the mold? I mean, is it pressed or melt? Sorry I don't quite understand the forming process of composite materials. Guess it must have been different from metals such as steel sheets.

- Vincente
User avatar
vincente
Poster
 
Posts: 30
Joined: Mon May 14, 2012 9:02 pm


Return to Autodesk T-Splines Plug-in for Rhino modeling

Who is online

Users browsing this forum: Bing [Bot], Yahoo [Bot] and 4 guests