New to FreeCAD and CAD, need help tracing out and enlarging parts...

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basslord1124
Posts: 2
Joined: Sun Feb 23, 2020 12:51 am

New to FreeCAD and CAD, need help tracing out and enlarging parts...

Post by basslord1124 »

All right I am totally new to using any kind of CAD program, but I know it will beneficial in some things that I do. I am an RC pilot who likes to build RC airplanes. And I'm wanting to venture into modifying existing plane designs and maybe do my own at some point. I hope to eventually take these designs and start doing things with laser and 3D printers too. I mainly use foamboard, foam, and wood for the material.

To sort of start into doing CAD,I have this project of making a foamboard version of the Travel Air Mystery Ship. There are really very few already existing plans for the plane itself...all I've been able to find are some old smaller balsa wood plans. I want to take these existing plans and enlarge some of the basic shapes and parts and cut them out of foam and foamboard.

I added a sample pic of the plane to give you all an idea of what I am wanting to do. I currently use FreeCAD 0.16 on Linux Mint 19.3 Cinnamon Edition. I can open the jpg in the program but just not sure what tools/workbenches I need to get started.

Those who also do this will take the parts/plane, and put those into a tile PDF format that can be printed on a standard printer. Appreciate any help. In the mean time, I'll try and play around some more and see if I can figure it out a little. Thanks a bunch!
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jmaustpc
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Location: Australia

Re: New to FreeCAD and CAD, need help tracing out and enlarging parts...

Post by jmaustpc »

Hi, welcome to FreeCAD.
basslord1124 wrote: Sun Feb 23, 2020 1:26 am All right I am totally new to using any kind of CAD program, but I know it will beneficial in some things that I do. I am an RC pilot who likes to build RC airplanes. And I'm wanting to venture into modifying existing plane designs and maybe do my own at some point.
You have picked one of the more difficult complex things to model, I suggest you learn the basics of FreeCAD on more simple things first, there is quite a steep learning curve.

A couple of tips, re PDF ... you can, at least in theory, print a 2d drawing of an outline and then use that as a template to cut out your material my hand but getting your printer to print 100% true to size is complex as it depends several different things on your computer. I got it to work once but only ever with one rather expensive at the time HP commercial printer.

Some laser cutters take DXF as an input for its path. DXF export is going to be problematic where you have splines rather than circular paths. You may want to try the legacy DXF exporter in some cases.

If you decide to use the Path workbench, you will likely do better with the development branch version of FreeCAD currently 0.19 as Path WB is under development and is much improved in a recent dev build of 0.19.

Jim
Linear3000
Posts: 13
Joined: Sun Feb 23, 2020 1:10 am

Re: New to FreeCAD and CAD, need help tracing out and enlarging parts...

Post by Linear3000 »

I'm not an expert on this, but when I saw your post I remembered this video that shows some nuances of replicating the geometry of a coca-cola bottle using the "image workbench" and a button "create a planar image in the 3d space"....which allows the guy to bring the image of a bottle directly onto a plane where you can make a sketch. you'll probably need to turn off the music and use the speed features to slow the video down to see the details of what this guy is doing. You can probably apply the techniques he is using for the cola bottle to your own project.

https://www.youtube.com/watch?v=i0S3CN16VoQ

Oh, also this:

https://www.youtube.com/watch?v=UYIfG1oqvsg
Last edited by Linear3000 on Sun Feb 23, 2020 4:10 am, edited 1 time in total.
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bejant
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Re: New to FreeCAD and CAD, need help tracing out and enlarging parts...

Post by bejant »

Hi, and welcome! I agree with what jmaustpc wrote, and I see Linear300 replied as I'm writing this, but I can offer some information to get you started.
Linear3000 wrote: Sun Feb 23, 2020 4:05 am using the "image workbench" and a button "create a planar image in the 3d space"....which allows the guy to bring the image of a bottle directly onto a plane where you can make a sketch.
I agree with Linear3000 too, first you'll have to bring your image into the FreeCAD document by opening FreeCAD, creating a new file, and from the Image WB select the second Image WB tool (the tooltip is just as Linear3000 wrote: "Create a planar image in the 3D space".

After Importing the Image, select it in the history tree, then use the Data tab (by default it is in the lower left corner of the FreeCAD window), click the property > Placement to expand it, then click the Position property to expand it too, and change either the X, Y, or Z position (depending on which Plane you used to Import the image) a tiny bit in the negative direction. This is so that as you trace over the image, the image doesn't obscure and is just behind the geometry you create.

You'll have to change the size of the image in order to make it life size, and that is done by again selecting the Image in the history tree and changing the Property XSize and YSize.

The Sketcher line segment I created for the wing span is just under 87 mm, so you can use that to calculate how large the Image should be. Using the Sketcher WB takes a bit of learning too, but maybe the attached file will offer a start. You should also download and read the Sketcher tutorial for which you can find a download link at the bottom of this forum post:
https://forum.freecadweb.org/viewtopic. ... 04#p248329


Here's a link you can use as a starting point for whenever you might want to look up some documentation, and this will be on your computer if you downloaded or installed the documentation package.
https://www.freecadweb.org/wiki/Workbenches

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OS: Ubuntu 18.04.4 LTS (ubuntu:GNOME/ubuntu)
Word size of OS: 32-bit
Word size of FreeCAD: 32-bit
Version: 0.19. (dated 2020-02-20)
Build type: Release
Build type: Release
Python version: 3.6.9
Qt version: 5.9.5
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OCC version: 7.3.0
Locale: English/UnitedStates (en_US)

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basslord1124
Posts: 2
Joined: Sun Feb 23, 2020 12:51 am

Re: New to FreeCAD and CAD, need help tracing out and enlarging parts...

Post by basslord1124 »

Wow, thanks for the help guys. I may try and play with it some more tomorrow.

I honestly thought that what I was asking for was a sort of simple thing but turns out it must be complex. I should mention,that the little details are not really that important at this stage. As long as I can get the basic shape of the wing, fuselage, and tail section that would definitely do for now. The models I do are cheap and don't have to be perfect.

Also, don't have a laser cutter or 3D printer at the moment...that may come later as well. Right now, I just want to print the paper plans out of the model so I can apply that to the foam/foamboard.
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