|Jan 09, 2011, 08:04 AM|
That is as it always is --- I'm not a professional - the Script is the second attempt to dig into something softwarespecific I did not originally learn!
My second impression is that , when it comes to more complex scripts ... that stuff is gettin very fast very slow !!! I actually try myself to implement a kind of basic 2Dcam for one go routing including the automated tab thing . but that is just for to evaluate the posibilities!
At the moment I try to find the right command to get the amount of 1st dimension cells in a 2 dimensional array back! THe array contains a unknown amount of 3D coods - I just would like to know the amount of 3Coordpackages I created with a closed function!
|Jan 09, 2011, 01:09 PM|
Ten hours later ... Performance is still low but who cares ...
Now I know how I would start this project so I would go for it again ..... more administration and better organized workflow ... but that is always the way of a study!!!
As soon as the video is available! ...
|Jan 27, 2011, 09:40 AM|
So.. time to going a little over basic functions..
I want to draw a balsa wing, with lightening holes, tube holes, and so on.
Suppose that i don't have "Profili" or "Foile-me" or any else software.
I import the airfoils in Rhino.
I make a loft between them.
I draw eleven 2D surfaces.
I use the surfaces to extract the sections (command "Section").
At this point i have a base for the wing ribs, and now the problems starts.
First : i want to draw the spars and the stringers.
The problem is that the wing is tapered so it is not enough to draw a square or a rectangle and extrude along the wing.
The only way i know until now, is to make the extrusion, then using the "Rotate" command i must try to align it to the ribs, but doing that i obtain an hole that is not square between the ribs.
Can someone teach me what is the trick ?
p.s. : this is only the first problem, more to come...
|Jan 27, 2011, 09:56 AM|
experimenting... i have found the solution at the first problem !!
Instead of "Extrude Surface Straight", i have drawn a polyline between the two ribs, and then i used the command "Extrude Surface Along Curve", and it works !! no more "rotate" ehehe
|Jan 27, 2011, 03:53 PM|
You can also use rail sweeps to extrude along a curve that is not just a straight line.
|Jan 30, 2011, 08:12 AM|
For wings and fuselages that are a bit less than straight, I tend to generate the curve along which to extrude by the intersection of e.g the fuselage skin and another plane - generally a cut plane.
|Feb 02, 2011, 01:23 PM|
Joined Dec 2010
This one goes to all rhino addicts out there: Here is a great source of rhino tutorials that I found some time ago and thought is worth sharing. Personally I have benefited a lot from them. I think I' ve rated 5* almost all of them.
Be warned though: Most of them are not for the very beginner. But once you 've taken your first baby steps with rhino these will bring you to the next level.
Sadly none of them is aviation related, still the technicks learned are applicable to almost anything - I think.
Maybe you'll also want to check this guy's work out. It's outstanding. Free registration is required for most of the tutorials.
Hope you enjoy.
|Feb 08, 2011, 10:01 PM|
Boone, Iowa, United States
Joined Feb 2002
Does anyone have any secreats on how to design an elliptical type wing such at that of a spitfire or P-47. Mine just dont seem to come out right. Any help would be greatly appreciated.
|Feb 09, 2011, 08:02 AM|
Let's say the biggest ingredient is patience and precision.
I have two methodologies for you.
Method 1. Two rail sweep
If this works, its the easiest.
1/. Draw a half wing outline using the curve draw tool.
2/. draw a spanwise line to intersect it at the actual tip..zoom in to get this pixel accurate
3/. SPLIT the outline with this line, into two open curves.
4/. darw a root rib outline at the center sectoin, perpendicular to the lines already drawn.
5/. sweep this cress section down the to rails.
6/. optionally CAP it if you want a solid.
Now this works well for constant sections and no washout etc.. If you want those.. try this method.
Method 2: Lofting.
I use this on propellors a lot because I have yet to find a way to get twist and section change into a swept surface.
Here you simply construct a LOT of cross sections and loft them. The secret to those cross sections is to be very meticulous in planning them. Any minor inaccuracies can put a wrinkle in the surface. As can any inadvertent discontinuities.
1/. For MOST of a wing or prop, where I am only changing chord thickness and twist (for washout) I start with a root section, or perhaps a mid span section, and copy it up and down the span first. Use a lot of VERY close spaced sections at the tip to get a wing that isn't obviously 'squared off' at the tip. The final section will be minuscule but it needs to be there.
2/. IF you have made or feel happy to make a front view, use scale 1D to adjust each sections height to the correct size in the vertical plane.
3/. Use scale 1D to adjust the chord lengths in plan view.
4/. If you want washout, you will probably have to do this 'by eye' or calculate each sections offset from the centre section and multiply that by some angle to give the correct rotation of each wing cross section.
5/. Trial loft with 'history' on. Lofting is a weird process. If the curves are good use a tight loft and rebuild to remove wrinkles. It your curves are not so good use a looser loft, and then tweak the sections till the whole thing looks right. Then cap it .
Harpye who is the Guru of curve networks, is probably better to explain how a wing top and bottom shell might be made using those techniques.
I stress that the secret is not in magical commands, but in using what the software has and doing the hard work to get the est out of it. Lofting takes a second: setting up a loft can take hours.
Finally, sometimes its better to split the job. For example a canopy is a good place where a curve extracted from the rear fuselage, a curve constructed from a side view, and a curve formed from intersection of the plan view with teh fuselage, can form the basis for your canopy surface: Likewise a fuselage WITH such a canopy (think hurricane) is easiest to form in two halves..a front half and a back half, joined together. And then a third bit - the canopy - made from the curves extracted from the first two bits.
In other words, study the outlines and shapes, and think of ways to split the job up. I had to so a wingtip formed from tissue covering over a rib and a flat plated wingtip. No way to make that part of the main wing sweep. I think surface from edge curves' got me the best result in the end.
|Feb 15, 2011, 09:46 AM|
Gentlemans, this is the way that i use to lighten my formers.
Tell me if it's the correct way or too much complicated, or even if there is a better/faster method :
1. With the former already shaped, i use the command "duplicate face border" and i get the contour.
2. I apply the "offset curve" command on this curve, in the following examples i offset only 6mm (not good for real applications i think).
3. then I apply the "fillet corners" command with a radius of 5mm.
5. then with the command "MakeHole" i empty the inside of the former.
This is done one by one for each former.
|Feb 15, 2011, 09:57 AM|
I'm also trying to put all those steps into a macro or script, so it does it automatically or semi-automatically.
But at this moment, i don't know how to do it...
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