anyone have any insight on drawing rails on a cnc shaping program?? up till this point, all my rails have been shaped by hand and feel. trying to do it on a computer is difficult for me. what, just draw the outline how it looks on one of your boards?? and im assuming the segment drawn in, is in the middle of the board. using the aku drawing system. any info. would be helpful. or pointing me in the right direction regarding past threads will be helpful too. peace and aloha "from da islands", OUT!!!!!!!!!
Think like the programs in slices/cross sections. Take wires and bend them around rails every 6" inches from stringer to stringer. Scan in those curves or hold them up to your computer screen.
They are highly complex curves to visualize. Just stack all those wires together and see how rapidly they change up and down the board.
I use Pro/Engineer which has very powerful surface modeling capabilities.
Here’s a Pro/E snap shot of the tail of a board showing the 3 trajectories, a few
of the offset values and the two conics which form the profile of the rail.
It’s tough to visualize 3D on a computer screen, Especially if you can’t
spin it around a bit. -Hein
Sounds a bit complex compared to Aps/Akushaper/Shape3D/etc. if you ask me, but it will give you a smooth rail for sure. How do you define the deck crown?
Hein, From my experience, One of the major disadvantage in surface creations using 3d software is the time it takes to actually design a board that will perform as desired. You can spend countless hours and weeks of time to design a single board and find out it comes up short on performance.
I found it’s much easier to actually start from a plug or blank and or a proven design and alter by hand or design and reshape a master and then do an actual 3d scan by picking up actually tens of thousands of 3d points and coordinates and not relying on cross sections slices as these couple points lock you into limited surfacing. I found that to actually get the true essence of the shape you need as many points as possible. Once you have scanned the desired shape in 3d you now have a proven design to alter in true 3d with out changing all the subtle essence that is hand shaped into the board. The time from design concept to actual working model is shortened tremendously. 2d converted to 3d will only give you a board that would be considered a fairly close facsimile but not really close to the actual board desired. If you were to overlay the actual 3d scan over a 2d surface with created 3d surfacing the algorithmed surface would have too many deviations to count. Depending on the size of board the differences in deviations would be inches if not feet along the entire surface. Relying on cross sections and algorithms to create surfaces will not give you a true scan.
As a hand shaper/designer, when boards are created the shaper isn’t calculating and relying on algorithms to smooth out the shapes. Shaping by actual feel and sighting down the board and how it all blends in maybe duplicated on screen, but it’s not the same for me. The are many compound curves and subtle areas that bend and blend. Just by picking up a couple points along a cross section will not allow you to get the correct surface. I can usually tell boards that have been created in 2d and converted with algorithms that have been smoothed and created over just a few points along the surface, they are all overly smooth surfaced with out that extra something that comes from a hand shaped board from a master shaper. Great for profiling and roughing out but, IMHO, not very exacting.
It does create a nice surface if I may say so myself.
You can see that by how smooth the gradient of the shading is.
(provided your monitor supports enough shades)
The deck is a curve that has a series of 3 arched cross sections.
It’s called a swept blend and is less complex but lacks the edge
blending control of the variable section sweep. In Pro/E you can
have the surface fall through the spine curve or have it follow
loosely. The latter provides a smoother blend but gives up some
control of the topology. Sometimes it’s better to provide a loose
frame work and then let the surfaces flow base on their mathematical
characteristics rather than unnaturally constraining them with a lot
of confusing and useless geometry.
Quote:
The are many compound curves and subtle areas that bend and blend.
Just by picking up a couple points along a cross section will not allow
you to get the correct surface.
I agree that section control does not provide great surfaces. You need a
high end CAD solution with quite a bit of experience building 3D surfaces
to accomplish that. But is is quite easy after that. And can provide very
precise smooth flowing surfaces.
Quote:
It does create a nice surface if I may say so myself.
You can see that by how smooth the gradient of the shading is.
(provided your monitor supports enough shades)
The deck is a curve that has a series of 3 arched cross sections.
It’s called a swept blend and is less complex but lacks the edge
blending control of the variable section sweep. In Pro/E you can
have the surface fall through the spine curve or have it follow
loosely. The latter provides a smoother blend but gives up some
control of the topology. Sometimes it’s better to provide a loose
frame work and then let the surfaces flow base on their mathematical
characteristics rather than unnaturally constraining them with a lot
of confusing and useless geometry.
Hein, Curious, How much time do you have in that paricular shape? And have you actually milled the board, and have you double checked with the cad and actual shape?
yes, I agree using cross sections it does mathematically create smoothed out surface. but at the cost of detail by locking the design in by only a few cross sections. Is the loose framework fuzzy logic? Kinda like when your shaper goes on a binge? lol.
I’m sure I have over 100 hours in that model. But it has produced 10
or so different boards and continues to evolve. Each time I start a new
shape I use the same model and modify it to fit the needs of that board.
It’s almost like a bit of software itself since each dimension is always a
variable and there are mathematical and geometrical relations that tie them
together. Pro/E provides the interface and programming language for the
model.
There is no doubt that my CNC machines exactly what I have modeled.
I’ve made enough bad cuts to know that. I’m a hobby/small time builder
so I can make lots of passes and don’t even sand the machined blank. I
don’t even touch it with bare hands. And it goes on a tool when it’s
laminated
But it’s more about the math functions I can access in the CAD to control
the surfaces. There is magic there but it is difficult to explain here. And the
history that’s stored in those models is tremendous. I go back and check
dimensions in past models all the time. And I make a detail drawing with
overall dimensions and store that in PDF for all finished boards that I make.
Even if I make just one.
I have one basic tip for all CAD users at what ever level:
Save often & do your back ups!
(I used to preach that when I was CAD consultant)
And use CAD/CNC at what ever level you feel comfortable.
It’s fun to learn something new.
P.S. -and this is really cool CAD stuff…
The image below shows a fully shaped board and next to
it a core that has been unbent along the neutral axis.
Just a few key strokes and it updates along with the
shaped model. CNC tool paths follow along for the ride
as well.
Sorry to get a bit off topic. Surfboards are tough to model in CAD. And the rails are a real b*tch.
Hein, 100 hrs is pretty good and if it’s cutting exact what you want and what more can you ask? I wish I had the luxury to spend 100 hrs on each board. For production purpose it would take way too long especially for an unproven design. There are many machine operators claiming to scan by using the 2d manual cross section inputs and claiming they have scanned a board, but the difference is very noticeable.
Many unsatisfied and disillusioned machine owners and customers. Caveat Emptor, do your due diligent if you are going to spend your hard earned monies on a CAD CAM system. Some machine operators and mfgrs are claiming do be able so scan, but it’s not a true scan in the true sense.
Sorry to hijack this thread.
Hein, Please post some images of your cuts especially if you aren’t actually finishing them at all. I would like to see images of the swallow detail. I could theorhetically make my passes micro sized and have virtually no hand finishing needed but the cycle times sitting on the machine making micro passes would not be any benefit on the back end when an expereinced shaper could hand finish a shape in a few minutes but the machine could take hours to make micro passes.
How much time would it take to draw this swallow detail in 3d? 
Hein, what machine are you using to cut your ProE files? Are you still in Santa Cruz?
Oak, what machine do you use to make those amazing swallowtails?!?
kirk
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Oak, what machine do you use to make those amazing swallowtails?!?
kirk
hi kirk, It’s a fully custom machine built to spec. All custom in house fixturing made and designed from the same machine that actually mills the boards. Not cheap. Began in 1987 down this long road, by the time I was satisfied with the product it was winter 1996. lol! Since 96 I have made many changes and major improvements…
I use a MultiCam 3 Axis CNC Router with 7HP spindle and 8 position tool changer.
Here’s a couple shots I may have posted already that show the machined surface.
There is no visible scallop. It’s smooth Takes about 30-40 minutes per side machining
time. I’m usually doing some manual prep work while the machine is running. Or
programming the next sequence.
The swallow tail wouldn’t take long to model in 3D. An entire board with
that tail could take a few days to model and program. Sorry, but I am not
in California. I live in Oregon. (And I am a kite surfer.)
sorry, i thought you were Andrew from Apex Surfboards.
kirk
I am a 3D Modeler by trade. I have no real handshaping experience, but I’m on my way. So, to get started I have been watching all the learn to shape videos.
The thing I have noticed is that the handshaping process seems to be relatively consistent from video to video. The goal is to find your shape within the blank by removing material. It is reductive. The steps with in the process are very logical and the order in which they occur is specific. For example, if you where to try and cut your rail bands before you cut your plane shape and adjusted your deck and rocker it would be a nightmare. That is because the rail banding process relies on the curves in the rail that were generated from cutting the plane shape and adjusting the deck and bottom rocker. Those curve are very complex. You use them to guide your planer when you do your rail bands. It’s inherent to the process. To draw those curves freely is nearly impossible.
3D modeling is mostly an additive process. You put points in dimensional space, curves pass threw the points, and the sum describes a volume(your board). So, I think this is the mental leap with which shapers are struggling. The current state of shaping software seems to me to be primitive when compared to some of the more sophisticated programs. But as I have discovered with almost all computer tools, the more control you want the steeper the learning curve. What Shape3d and Aku are doing is providing a user interface to building models that would be extremely complex to draw freely with curve tools.
I think that the Ui’s and the tutorials for how to use the current shaping software packages will need to improve for the none computer board builders to take them up and put down there planers. They need a well defined process for working with the software.
What Hein has accomplished is very sophisticated. He hasn’t just modeled one board, he has essentially written within Pro/E his own shaping software. Nice!
hein, very nice work. I also use a 3-axis with custom made cutters to optimized step over and kellering and maintaining nice rail detail and maitaining the tucked edge. a kite board on my 3 axis will cut two boards is approx 3 1/2 - 4 min. Hand finish time will only take 5 min or less.
Hi Hein,
just been thinking of this, but how does using three offset lines differ from akushaper/shape3D? Basically you sould get the same from designing a outline and a profile in Aku/shape3D and then defining a square crosssection. This is your starting point. Next in aku or shape3D you would add three control points which you offset from the apex of a the rail. This is the same as the offset lines in the cad package. Then add any number of crosssections to get the adequate control similar to the curves in CAD. Then the tangents define the curve you would otherwise sweep through the lines. The only real difference I can think of is how the interpolation is done, aku seems to do a linear interpolation between crosssections, while Shape3D seem to use beziers (curves) for the interpolation which is closer to what your CAD package is doing. I can see the CAD package giving somewhat better results than Aku, but I cannot quite see it giving a much smoother surface than Shape3D as it seemingly is also sweeping and blending curves in much the same manner.
Someone else pointed out that the surfboard CAD packages are less advanced than the general purpose packages. But the general purpose CAD packages have a steep learning curve and takes a long time to finish your design. I’ll give you another example: You could design a house or a building in AutoCAD. You could layout the ventilation and electrics wiring in it too. Or you could use a purpose made CAD package like www.dds-cad.net which has a simpler user interface and is geared towards making houses. In addition it will do such things as calculating adequate ventilation and windows size for good daytime lighting, check that the house is according to rules and regulations, check that the framework is stable and sound, provide cut list and part list, etc. and integrate this with electrical wiring and HVAC cad packages. So what would you choose? I think much the same goes for surfboard CAD packages, while they use simplistic surface models I have a hard time seeing that a more advanced surface model would provide significantly better results. And they do provide everything you need from start to finish for making a surfboard with a machine. While I could design surfboards in Lightwave, 3D studio MAX, Rhino, AutoCAD , etc. (and have) Akushaper or Shape3D will get me there in much shorter time even though I might be using the same kind of design tools in the cad packages.
regards,
Håvard
Some nice advice above.
I had to figure out how to do rails on CNC software because I kept getting wobbles in my decklines.
I learnt how to set rails up by numbers - now I have rails I can grow or shrink and maintain proportions.
In your software of choice:
-
Set the rail extreme point. This will be the middle point (not necessarily midpoint, tho)
-
Go up, say 1/2" (y-amount) and in towards stringer say 1/4" (x-amount) and set an intermediate point.
-
If it’s a 50/50 rail, do the same at the bottom (1/2" down, 1/4" in). This will probably be where your rail meets the bottom. This can be smooth or give an edge, depending on what you want.
-
Set a point at the top of the rail (maybe 1" in from the point in step 2. and a bit above it) to bring the flow into the deck line. I generally try for a slight chine there to promote water breakaway.
-
Flow the curve from the stringer through the top 2 points to the midrail to the bottom point. The curve should get progressively tighter into the bottom deck.
The benefit of doing step 2 using the same x/y proportions for all your slices is that your top and bottom decks start to line up better through the slices and you eliminate wobbles down the length of the board (some hand tweakiing may be necessary, tho).
The x-amount gets really small for boxy rails (say in the tail).
The y-amount gets small up front
Then if you want to puff up / reduce the rails you simply adjust the x/y proportions equally in all the slices.
Once it’s right add them to the rail library for mix n match with outlines and rockers.
Last post
Bye
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The only real difference I can think of is how the interpolation is done, aku seems to do a linear interpolation between crosssections, while Shape3D seem to use beziers (curves) for the interpolation which is closer to what your CAD package is doing. I can see the CAD package giving somewhat better results than Aku, but I cannot quite see it giving a much smoother surface than Shape3D as it seemingly is also sweeping and blending curves in much the same manner.
The only real difference I can think of is how the interpolation is done, aku seems to do a linear interpolation between crosssections, while Shape3D seem to use beziers (curves) for the interpolation which is closer to what your CAD package is doing. I can see the CAD package giving somewhat better results than Aku, but I cannot quite see it giving a much smoother surface than Shape3D as it seemingly is also sweeping and blending curves in much the same manner.
We don’t use linear interpolation, we use a spline interpolation for the cutting paths. It is this cutting path algorithm specially designed for surfboards and the capabilities of our machine that actually makes our cuts better than you would get with a general CNC machine and CAD software unless you are talking about very expensive machines and software. As Havard points out, it is much harder to design using the general CAD software.
The mathematics we use is actually more complex than what we thought we could originally get away with. Using a more advanced controller has also helped iron our the very small waves in the foam that were more cosmetic, for the most part, but also indicated that the cut on the board could be improved.
Jimmy Freese
Aku Shaper