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Old Dec 04, 2009, 09:16 AM
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Calgary, AB, Canada
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Quote:
Originally Posted by FlyDave View Post
Say that this cilinder is a fuse and the outer part is a "skin". There is a plugin to develop this "skin" to a 2D drawing ?
No plug-in required. If its a developable surface, its just a button click. Here is a tapered cylinder for example.
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Old Dec 04, 2009, 09:43 AM
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Quote:
Originally Posted by SDST View Post
I thought I would submit a brief description of a technique that has worked pretty well for me.
NICE! Can you elaborate, I think that might be part of where I go off track off track.

>> minimum five control points; two at each curve end to establish tangency and at least one in the center of the curve to establish curvature. In this example, I used six. Use Curve Match to make these tangent with the split edges of the wing and fuselage and adjust the curve center points to obtain a full radius<<

Ive mesed with CurveMatch but I dont think Im using it properly or to my advantage. Are you saying you are making a 'new' curve using this command or forcing tangency from existing section curves for the in-between part?

What is significant about 5 or 6 control points? You need more to make 'nice' surfaces from highly deviating type sections? I never sem to know the difference when people say 'less is better'.
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Old Dec 04, 2009, 09:49 AM
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Quote:
Originally Posted by SDST View Post
I thought I would submit a brief description of a technique that has worked pretty well for me.
>> Avoid using an airfoil with too sharp a trailing edge. For this example I recall using a trailing edge "point" with an .06 radius (on the full size drawing <<

Thats weird because the ONLY way I can ever seem to make my TE fillet 'dart' segment into teh fuse is to a point as opposed to a radius. Can you elaborate
- you are doing an upper fillet surface & lower fillet seperately, right?
- I see your fuse section airfoil has a TE radius, but is the wing TE also a similar radius section vs a point vs a rectangular termination? (My wing airfoils go to a point).
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Old Dec 04, 2009, 10:07 AM
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t-splines for rhino

Quote:
Originally Posted by SDST View Post
MCG started a thread in the T-Splines forum about drawing wing to fuselage fillet fairings with Rhinoceros.
Are you talking about the P51 post?

<edit> never mind, I just saw this posting too "How to fillet a keel or wing root". Oooh, how exciting, I must get my forum account set up!


I just purchased TS but just been short on time to play with it, so Im near clueless. Its on my list! But when I look at the nice finished surface & how (apparently) simple the box mode looks, this is exactly why Im intrigued by this program. A good kick in the pants to follow that post & learn, thanks for posting!

Are you using TS yourself?

This TS dolphin example blows me away.
http://www.tsplines.com/dolphin.html
But all I kept thinking about was... nice organic surfaces, but I wonder if the dorsal fin (wing) were a defined airfoil, could it similarly be blended into the body (fuse). Fillets... again!!
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Last edited by ptxman; Dec 04, 2009 at 10:27 AM.
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Old Dec 04, 2009, 11:13 AM
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Projection or unwrap ... Projection will give you a kind of technical drawing ( 2D )
Unwrap does just work with non sperical surcafes - not Surface groups ..
you would have to explode the surfaces take the outher skin and use "unroll developable surface"
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Old Dec 04, 2009, 05:18 PM
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Quote:
Originally Posted by ptxman View Post
No plug-in required. If its a developable surface, its just a button click. Here is a tapered cylinder for example.
Thank you so much !!

Incredible how many features has this program !!!
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Old Dec 05, 2009, 05:48 AM
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ptx: The added curves (arcs) which will form the forward and aft edges of the center fairing panels should blend tangentially with the edges of the fuselage and wing splits. G1 (tangent) continuity requires two points. Curve Match modifies a curve and ensures tangency by aligning the curve Control Points with the Control Points of the "matched" curve. Draw several curves and experiment with Curve Match; it's a very useful modifier.
Fewer Control Points are "better", not only for efficiency, but mainly for editing. Most Rhino surfaces have so many points it's impossible to edit the surface by moving points. In this case, it's easy to move one or two points to shape the fairing end arcs.
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Old Dec 05, 2009, 05:52 AM
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You like "Box Modelling" ? ... perhaps you should google for SILO ....
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Old Dec 05, 2009, 05:55 AM
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ptx; Look at the TSpline post about wing fillets, notice the screen print showing the airfoils; the airfoil like we're used to using in Rhino has been reduced to only eight Control Points.
Regarding the "sharp" trailing edge, an .06 radius on a 95 chord is pretty sharp! For me using a curve here "helps" the trailing edge blend into the fuselage curve.
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Old Dec 05, 2009, 09:36 AM
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Quote:
Originally Posted by Harpye View Post
You like "Box Modelling" ? ... perhaps you should google for SILO ....
Im not up to speed on this, maybe you can answer. T-splines is a rhino plugin that results in nurbs surfaces. So aside from other advantages, you can export this to a 3d cnc surfacing router etc to make molds & plugs. Most of the other programs I see that make those amazing detailed creatures are 'faceted' or 'mesh' (are those the right words?) and dont have this capability. Would you say that is accurate or maybe Im misunderstanding?

Mike has some amazing detailed aircraft drawings using a program called mojo. I wonder if its the same issue - what to do when you want to 'make' the model, resort to 2d sections etc?

http://www.mikejamesmedia.com/cfm_03.html
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Old Dec 05, 2009, 10:31 AM
Build it again, Sam!
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NURBS and Splines are a mathematical ( abstract) way to define surfaces and lines.
A more discrete way to result in roughly the same is done in OBJ and VRML formats ... the surface is analyzed and stored in discrete faces or texels what is a kind of down grading of information - putting this back into NURBS again will cause a loss of information... but this way is much easier to handle....
"Mesh" is just the common expression for a construct of nodes and connections however it is defined... ( that is what I guess)



STA or laser sinter process is not that precise that the discrete objects ( until discretization is done very coarse way) would affect the precision of the model...

I once tried to import an .OBJ file ( standard not Tspline origin) to Sharp Construct ... it always had the problem that data caused a kind of seam, where the surface was closed! The result were some problems when transforming the data with the clay modellers -> warps and defects...
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Old Dec 05, 2009, 04:08 PM
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T-Splines creates very smooth seamless surfaces which are unique, can be edited and remain smooth, then can be converted to nurbs. TSplines also has a "box" mode which appears faceted. In my case, I would design in TSplines, convert to nurbs for detail design, then export in .stl format for use in CNC tool path program.
Mike James is amazing, and that site is fantastic.
Harpye, I tried Silo and Blender before buying Rhinoceros. I am amazed by what some people can draw with box modeling.
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Old Dec 05, 2009, 04:44 PM
Build it again, Sam!
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Since my Cad PC is defect I had to switch to my notebook ...lower performance... but then decided to design a 30 cm WS biplane for indoor use .. it refers to FSK s Chubby Lady ...- I dont like FSK but the plane looks nice .. just a quick proposal..
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Old Dec 07, 2009, 01:50 PM
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A question / suggestion:

I don't want to use the word "contest" as this would be a kind of competition ... but what about to take it the friendly way...

...the following suggestion: As we would define a plane of desire we could
start a kind of group built where everyone could participate from everyones knowledge and techniques... - The way it could work : everyone creates his own build thread and posts a link in here...

variants would be ..

Speed modeling
Scenery modeling ( render)

Any ideas???

Hansjoerg
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Old Dec 08, 2009, 01:35 AM
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Just my two cents, but that would seem to be outside the realm of Rhino Basics, as this thread has been nicely covering.

A group modeling project would be fun though. New thread? Just get ready for butting ideas and bashed egos...

C
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