Converting model aircraft plans into a 3D model for printing

[tommeyers]

Thanks Sal.

The goal Tony has is to 3D print his creation. do you have any suggestions on design choices for 3D Printing?

Tom Meyers

[TonyR]

Firstly - let me say a HUGE thanks to you guys who are helping me to try to learn this whole "CAD" thing.
To many, it seems to be an intuitive thing.
To people like me, it is not.
I really appreciate your help.

If the Mods feel that these posts should be under a different category, then please let me know where to find the thread/s. That would be a great help to me.

What I'm trying to do here isn't exactly Rocket-Science... yet, for those who don't understand the basics of CAD, it can be a bit daunting.

I soooo want to learn and master this thing. I have chosen FreeCAD over many other software packages because I thought I could learn it easily. It hasn't turned out that way so far. And there's been some massive changes between Win 0.16 and 0.17 as far as Part Design and Part workbenches go.

What I'm trying to achieve should not be all that difficult. In a nustshell, what I'm hoping to do is:
1. Import/trace some scale cross-sections into FreeCAD.
2. Arrage/assemble these cross-sections along an Axis so that they eventually produce a 3D-shell.
3. 3D print that shell.

The 'formers' that I have shown so far are just 2 cross-sections of a fuselage piece (the smallest and foremost parts of the nose-cone).

I don't want to print each former - I want to be able to extrude a hollow 3D piece section by section (Cura will let me determine things like wall thickness... bracing.. etc)

The model is an F-111 - it has somewhere around 26 'formers' (cross-sections) that I need to capture into FreeCAD somehow, and then assemble according to a distance (plan) view... and a a +/- offset relative to the central axis of all the bits lined up.

Each former is symmetrical through a vertical slice - i.e. the right hand side from 12 o'clock to 6 o'clock is identical to the left hand side from 6 o'clock to 12 o'clock.

Some of these formers - as the model approaches the wing-box section - are quite complex (see attached example).

What I need to learn from here on in is how to digitize each former into FreeCAD - it's OUTLINE - so that I can join all the formers together to produce a 3D mesh that I can import into Cura...and print each section as a hollow tube according to the fore and aft former for each section of the fuselage.

In short.. just renders of a front bit, and a back bit to form a 3D part that can be printed as an outline (skin) of the project.

[TonyR]

Example of a rather complicated cross-section...

s14 15.jpg (201.48 KiB) Viewed 641 times

[tommeyers]

Tony,

I too explored many other free and for pay 3D CAD systems. Some simpler and some more complex. I settled on FreeCAD and was determined to master it part by part as I needed capabilities for environmental sensor-enclosures and jewelry design. Looking back on that journey I think that although there are many seemingly disconnected pieces there are just a few necessary for my immediate work.

In your case the initial capabilities are : 0) Setup I/F; 1) Image import and scaling; 2) sketcher tracing including splines; 3) sketch offset plane; and 4) lofting to join formers; 5) design for 3D printing.

Which one are you stuck on?

Tom Meyers

[TonyR]

Right now?

*embarrassed look*

The first bit - digitizing each former into a FreeCAD object so that I can assemble them at their correct offsets to produce a 3D object suitable for 3D printing as a hollow shell..

[TonyR]

Soooo... what I'm basically trying to do - step 1 - is to somehow digitise those first 2 formers that end up extruding a 3D shape that looks like this:

i.e. 2 traces of the fuselage contour via the cross-section... then turned into a 3D printable 'mesh''

It will be hollow - the printer will print something along the lines of a bottomless paper coffee cup.

The wall thickness and/or support webbing + inner skin I can do via the Slicer (Cura)

Just need to somehow get the 2 formers into FreeCAD and extrude the shape so that it produces the attached example...

[tommeyers]

Tony,
Here are steps to follow:
1) Open FC part design WB -- new -- add a part
2) open image WB -- image icon 2 - choose image -- xz plane -- view front face
3) sketch wb - sketch use periodic b-spline z-axis, 2 points in quadrant, x axis ... (trace) last point make coincidentwith forst point
(when it is coincident the point changes to yellow.)

When you can do this we can continue, Tom Meyers

[salp]

Tony,

What I need to learn from here on in is how to digitize each former into FreeCAD - it's OUTLINE - so that I can join all the formers together to produce a 3D mesh that I can import into Cura...and print each section as a hollow tube according to the fore and aft former for each section of the fuselage.

As far as I know you will not be able to digitize the images (I have tried several different ways and failed every time), to keep you sanity you need to redraw them in FreeCAD, for arguments sake lets choose Sketcher Module as the tool to use (look at the example below, its only 3 sketches and the Loft tool).
Have you been able to create any of the cross-sections so far? To get started post a FreeCAD file that you are working on, so we take a look as to see where your stuck (it sounds like you are still in the drawing cross sections stage).

Once we get the envelope of the plane figured out than we can worry about the 3D print work flow.

Sal

Plane_test.fcstd

(21.83 KiB) Downloaded 23 times

[bejant]

Maybe this is helpful, maybe not.

20180512a.png (75.62 KiB) Viewed 553 times

20180512-017-model-airplane.fcstd

(217.77 KiB) Downloaded 32 times

OS: Ubuntu 16.04.4 LTS
Word size of OS: 32-bit
Word size of FreeCAD: 32-bit
Version: 0.17.13522 (Git)
Build type: None
Branch: releases/FreeCAD-0-17
Hash: 3bb5ff4e70c0c526f2d9dd69b1004155b2f527f2
Python version: 2.7.12
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.2.0
Locale: English/UnitedStates (en_US)

[TonyR]

That's *exactly* right, Bejant

Totally what I'm trying to achieve