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Old Nov 14, 2009, 04:43 AM
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Quote:
Originally Posted by Haole View Post
Well last night I was bored and decided to start designing a model for my father. This is my first take at doing a complete elliptical wing structure in Rhino and I ran into some problems with making my lightening holes in the ribs, mainly that I had to manually edit each curve used for Sweep2 process to create the solids that I used to boolean difference the holes out of the ribs.

I found that even though I had created elliptical offsets for these sweep curves that the interpolation between the root rib and the tip rib was not vertically aligned as it passed though the elliptical planform, so in the end I had to bend the solid to give it a vertical bow (viewed from front) using symmetry in the bend command, then had to follow with manually moving the solid vertically until it was centered throughout the entire sweep of ribs. All three solids created for making my lightening holes needed to be tweaked like this until I was happy with the spacing.

Any tips for a better way to do this process where a simple lofting between two end curves does not apply?

Carl

If your wing started as a surface, I would be tempted to offset that internally to make a basic hollowing sort of shape, then slice that into three, and blend the edges of the 'punch tools'.

Another way would be to take your cross section curves and shrink in 2D and re loft or sweep them.


I don't exactly understand why your original method didn't work.
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Old Nov 14, 2009, 06:41 AM
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Haole's Avatar
Hawaii
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Oh, that's an excellent idea. Thanks very much--I forgot how useful the offset surfacing tools are (duh, since I use that to build almost every structural member of the wings).

I think that my first technique would have worked had I chosen rails that were tangent to the upper and lower edges of my wire curves, but I bet that the x-axis curves would have then been screwed up and required the editing...

Still, your suggestion to use offset will be so much faster than manipulating coring solids one at a time, though without being able to effectively harness variable offsetting of surfaces on an ellipse (without some more powerful kung fu than I currently possess), the offset would be constant and the holes would diminish towards the wing's tip. That's not necessarily a bad thing though. I will try it next round.

Here's where I stopped tonight. Need to build the fin, rudder, panted gear (tail-dragger) and then go to work slicing up the fuselage into bulkheads and stringers. Speaking of the fuselage, I'm really wishing that I had T-Splines right about now! I had a wrestling match getting the curves that I wanted on this model.

Carl
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Old Nov 14, 2009, 06:52 AM
Build it again, Sam!
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Create the Mesh from a bunch of crossing splines ... so spherical things or curved surfaces are really no problem!!!!!
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Last edited by Harpye; Nov 14, 2009 at 07:01 AM.
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Old Nov 14, 2009, 06:56 AM
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Harpye, not sure I understand you. Would it be too much to ask you to detail the method that you're talking about?

Thanks in advance if you have the time!

Carl
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Old Nov 14, 2009, 07:02 AM
Build it again, Sam!
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Sorry the upload did not work! take a look on the pic above... it is an easy sculpt I did since I read your post before a few minutes ... but it shows how it works...

use some splines as stringers create some ring splines as spacers and use surface from network of curves to mesh it... the more information you deliver the more detailed and the more challenging for your computing power .....

As you would share your fuses data I perhaps could help with this method ( but only as you would thrust in me - I promise that I will erase the file after doing this and do not further share )
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Old Nov 14, 2009, 07:13 AM
Build it again, Sam!
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T splines / Box modeling is NOT the proper strategy for anything!!!!!
For such a relatively simple fuse as yours is you are quite right with what you have done ....looking good!!!
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Old Nov 14, 2009, 07:13 AM
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Is that technique better than sweeping two rails through a series of cross-sections? Thanks for the help by the way--I'm learning new stuff every day that I check out this thread.

Edit: Thanks, I'm getting better at editing meshes and the fuselage is pretty close to what I had visualized.
Carl
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Old Nov 14, 2009, 07:20 AM
Build it again, Sam!
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Sweeping along two rails is always scaling the second dimension ( persistent to the connective line between the two corresponding sweep locations) with the
dimension between the two rails -> so sweeping a circle can scale the circle but never cause an ellipsis - with that multi curve function it can!!! so you have much more degrees of freedom!!

a further example with the relevant steps included:
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Old Nov 14, 2009, 07:38 AM
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OK, thanks. I have more questions about how you setup your wireframe so I will wait until tomorrow when my mind has begun working again--I suspect that there are some fundamental drawing processes that I do not understand. I appreciate your tips very much so thanks again. You make it look easy!

Carl
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Old Nov 14, 2009, 07:41 AM
Build it again, Sam!
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As I already mentioned! - I did a rhino workshop some years ago - the tutorial would exactly describe this method ... so send me your email and you will get the units...

... it shows just one way but is rather easy to understand!!!

BTW : Carl .. is Hawaii West Coast Time or is it another zone

Hansjoerg
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Old Nov 14, 2009, 05:33 PM
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Thanks! Sent you a PM with contact info. Hawaii is 2-3 hours behind the West Coast depending on the time of year (we have no daylight savings here thank goodness). I was up very late last night working on that model...

Carl
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Old Nov 14, 2009, 05:44 PM
Build it again, Sam!
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Hello Carl!
Here is rather midnight now... I'm just watching tv writing Emails on my laptop .. CAD PC is already down ... will send the documentation tomorrow!
Hansjoerg
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Old Nov 15, 2009, 10:52 PM
FrankC
Ocala, Florida
Joined Jun 2007
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where is the justice?

I look at what you guys are doing in Rhino and it is excellent. I have no abilities like this, I can't even draw a stickman. Vintage, the room you drew back in post 30 looks great. I wish I could do that, I need a darkroom image but would never get acceptable results. I need a table with the developer trays and some film strips hanging from clips. It would make a great wallpaper for a program I am writing. I can program, I just can't draw Keep up the good work guys.
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Old Nov 16, 2009, 12:19 AM
Sink stinks
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United States, GA, Atlanta
Joined Apr 2005
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Rhino looks really nice, based on the work you guys have been posting. Right now I'm using TC 14 Pro, which honestly does everything I need it to and is very easy to use, but Rhino has some nice modeling features that TC lacks, and in general I think it just looks better.

Looks like I could get it for <$200 on an academic discount, but it's probably not worth it. Maybe you guys should try to convince me.

P.S. I'm checking out the trial version now. I wish I knew all the shortcuts that I can do with TurboCad.
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Old Nov 16, 2009, 01:34 AM
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Hawaii
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Nice drafting! Looks like you're pretty proficient in TC. Looks like you'll have to decide for yourself which is better for your workflow, but Rhino for $200 is steal anyway that you look at it.

Carl
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