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Old Sep 09, 2011, 04:09 PM
JOE MOCERI
United States, MO, St Charles
Joined Nov 2006
28 Posts
Harpye, That flows real good. I will re read your email and try to figure out your reply back.
You are correct that I was sweeping between each former areas to get the surface and mirroring the other side. I have been trying a lot of different things for the past few days and you accomplished it a few strokes of your keys.
I may need a step by step on how you did it,. Once I figure this out I can move foward
Thanks Joe
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Old Sep 10, 2011, 05:47 AM
Build it again, Sam!
Harpye's Avatar
Germany
Joined Oct 2004
4,091 Posts
Create formers

Intersect formers with planes calculate intersechtion points

Create " Spline Stringers " trough the points of one Section .... refine the splines in areas of higher spherical complexity and so build a kind of complex tubularity which you afterwards can NURB mesh


Create NURB mesh -



THats all in short words ( I know that there may occur some difficuties but thatīs life
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Old Sep 10, 2011, 06:35 PM
JOE MOCERI
United States, MO, St Charles
Joined Nov 2006
28 Posts
Harpye, Getting closer, Lofted the formers in a couple of sections. Still have some warps in areas of a greater transition, especially at the lower tail area. What am I still doing wrong... I would like to get the file back I sent you the you have modified to review what you did.. Let me know.
Thanks Joe
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Old Sep 11, 2011, 06:26 AM
Build it again, Sam!
Harpye's Avatar
Germany
Joined Oct 2004
4,091 Posts
I did show you everything I did in the 3 Pics above - nothing else you could take out of the file.... which meanwhile is bit too large to be sent even when zipped

1 define the FORMERS
2 define the STRINGERS -Important for a smooth transition and the "flow" you mentioned ....
3 no pure loft - a loft is straight between two formers - a loft over more formers interpolates the surface but is not precise enough because it refers to the arrangement of the formers wich are only a few - so between the formers there is not enough definition given ... for what you need the longitudinal stringers.... If you work with the wire mesh shown in the three steps and mesh this in a hole part you would do right - and would get one part without warps and edges
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Old Sep 11, 2011, 08:54 AM
JOE MOCERI
United States, MO, St Charles
Joined Nov 2006
28 Posts
are you saying you lofted all the formers in one loft and meshed the surface. I tried this and it still looks some what dished in between some formers

3 no pure loft - a loft is straight between two formers - a loft over more formers interpolates the surface but is not precise enough because it refers to the arrangement of the formers wich are only a few - so between the formers there is not enough definition given ... for what you need the longitudinal stringers.... If you work with the wire mesh shown in the three steps and mesh this in a hole part you would do right - and would get one part without warps and edges .

I do not understand what you mean here. I'm new to Rhino, 3 months.. I think translation from German to English lost here or I am too green to understand...

Joe
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Old Sep 11, 2011, 11:00 AM
mcg
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Joined Jul 2005
704 Posts
Hello Harpye and Joe,

The step I cannot quite understand is the third step, "Create NURBS mesh."

On Rhino's feature list online, I looked up all the different ways to create a surface, and all the different ways to create a mesh. Here they are:

Create meshes: from NURBS surfaces, from closed polyline, mesh face, plane, box, cylinder, cone, and sphere.

Create surfaces: from 3 or 4 points, from 3 or 4 curves, from planar curves, from network of curves, rectangle, deformable plane, extrude, ribbon, rule, loft with tangency matching, developable, sweep along a path with edge matching, sweep along two rail curves with edge continuity, revolve, rail revolve, blend, patch, drape, point grid, heightfield, fillet, chamfer, offset, plane through points, TrueType and Unicode (double-byte) text.

In this specific fuselage example, it appears that you should create and refine a spaceframe using curves (representing formers and stringers), and then surface this spaceframe with a mesh. But this last step -- surfacing the frame with a mesh -- is unclear to me.

Is it accomplished with a Network of Curves command? Is the mesh draped over the frame? Is the surface created initially as multiple sections, and then Merged to form a single surface?

In other words, what are the specific Rhino command words that enable you to work with a wire mesh, and in this way transform the spaceframe of curves into a smooth, continuous surface?

Many thanks for your insights.

Michael
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Old Sep 11, 2011, 11:30 AM
Build it again, Sam!
Harpye's Avatar
Germany
Joined Oct 2004
4,091 Posts
Michael - I was off over the weekend and answered the questions via cellphone - was not able to refer to the Rhino commands list
Create "Mesh from Network of curves" ( submenue of " surface from 3or 4 corner points") is right...
The steps called above are steps in the meshing process but not Rhino commands
__________________________________

HI Joe - Skype would be that easy ... for English is far away from beeing my mother thoung would be much easier to explain interactively - that stuff is not that easy going over my lips... !NO PURE LOFT! meant you should not LOFT the formers but also use the "Stringers" to create a kind of line mesh you could easily coat with a NURBS mesh ( command - see above or in the Tutorial)!!!

THink about a wood built ... e.g. Guillows models - you need the formers connected by the stringers to be the wooden part of the airframe - afterwards you use Oracover to coat this structure to be a closed fuselage -

In CAD: the formers and stringers consist of open (= stringers) and closed ( =formers) SPLINEs like in a wooden plane kit and the meshing process overspans all the structure with NURBS mesh (= Oracover)
if you'd leave out the stringers and only use the formers - the coating result would be same as in reallity - you would get straight connections ( tubular elements between the formers but no sperical surface...)!
_________________________________

A loft - originally between 2 closed SPLINE curves causes a tubular element with straight isocurve lines between both edges...

extending this command and applying it on three splines causes a Spherical surface which intersects with al 3 SPLINES

Both is not the right method to control a Free Form Surface of that complexity!

you should do former - SPLINEs and stringer - SPLINEs and use the "SURFACE FROM NETWORK OF CURVES" command to mesh the whole thing ... THat is also what I've shown in the tutorial and in the 3 states of meshing shown above - first wiremesh - second NURBS Surface - and third - check surface with Zebra pattern
_________________________________

Another pic shown below:

3 closed splines ( yellow) - each example shows the same position of them

in the top straight lofts between 2two of them

in the middle a loft done over all 3 of them - see the difference - better but not enough definition for a complex fuselage

the third shows the 3 closed splines with 4 additional what I called stringers
you see that there is much more posibility to add information and definition of the " flow"

THis is also shown by the detail of the isobate curves on the surface created ... the third version is much more complex and detailed!
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Old Sep 11, 2011, 01:16 PM
JOE MOCERI
United States, MO, St Charles
Joined Nov 2006
28 Posts
Harpye your last post made it click for me. Did a network on the formers and the rails and i like how it turned out. Attached a picture of the rendering. Thanks
Joe
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Old Sep 11, 2011, 01:36 PM
Build it again, Sam!
Harpye's Avatar
Germany
Joined Oct 2004
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HI Joe!

Beg your pardon , beeing a bit unprecise in the first step of explanation... but typing on a blackberry keypad without the support of the program was someway a poor attempt as it seems! Main thing is that you finally understood what I'd tried to tell you ! ... Looks good - your first NURBS surface!

Hansjoerg
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Old Apr 10, 2012, 10:29 PM
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United States, IL, Northbrook
Joined Sep 2011
542 Posts
I am trying to model the wingtip droops on the A-10 but cant seem to get it right. I've tried 1 and 2 rail sweeps and it comes out close. But, the underside is too thick and isnt as bowl-like as it normally would look.

Any ideas?
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Old Apr 11, 2012, 05:55 AM
Build it again, Sam!
Harpye's Avatar
Germany
Joined Oct 2004
4,091 Posts
A pic / screenshot would help!

Otherwise ... create a more detailed crossed wire mesh and use surface from network of curve to coat it!!!
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Old Apr 11, 2012, 08:21 AM
Claus at Area 52
clausxpf's Avatar
copenhagen Denmark
Joined May 2002
2,533 Posts
wing tips for a 10

I worked my way through it mostly by use of use of "curved network "

Claus
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Old Apr 11, 2012, 01:24 PM
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United States, IL, Northbrook
Joined Sep 2011
542 Posts
I played around with the sweep rails and was able to get pretty close. The top and side profiles are spot on, but it has an abrupt change and just needs a bit more dish on the underside.

orange are the rails, gold are the cross sections.
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Old Apr 11, 2012, 03:33 PM
Build it again, Sam!
Harpye's Avatar
Germany
Joined Oct 2004
4,091 Posts
Try to get some additional curves for better definition of detail and do a fully free form surface mesh!!!Also take care on the tangential consistence onto the main wing surface!!
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Old Apr 29, 2012, 01:48 PM
71% of the world is runway . .
Bart83's Avatar
Nederland, ZH, Oostvoorne
Joined Jun 2009
1,687 Posts
So afer a lot of reading and having done the turorials in Rhino 4 i thought i give it a try and draw a part for my next project in rhino. And here ar the results:









This was fun to do.

So now i have the shape how can i make formers and sheeting etc?

Greets ,

Bart
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