Is it possible to design 3D woodturning projects with CAD on a Raspberry Pi

Hello Craigh,

Raspberry Pi is not that good for 3D rendering even while the GPU is not that bad, it's quite short on memory for this kind of task.

I have a gantry CNC router and use to mechanize aluminium on it. It's not the same as a lathe - I would love to have one - but the tools at hand are quite close.

The program you show does what is called 2 1/2 CAD design. You get a 2D CAD design, and extrude a height to make a 3D piece.

Usually this is done to create a tool path to let a CNC enabled machine - router, mill or lathe - to read that paths and make the cuts, pockets and shapes designed by that CAD.

If you want to know the tools I use for that - in my case I use to just cut few mm to few cm height pieces - for the 2D design I use LibreCAD, or Qcad - they have the same heritage.

It's a 2D CAD where you draw the circles, pockets, contours and lines in 2D that define your design Home of LibreCAD, 2D-CAD

In some cases - where the cuts involve text - I even use inkscape, that's an really easy to use SVG draw program-

After that I use PyCAM. PyCAM is a python program that lets you load your 2D design and extrude it to 3D to let you make a 3D part. It also calculates the toolpaths for milling it, but I don't think it would work on a lathe. PyCAM - Toolpath Generation for 3-Axis CNC machining

PyCAM can export to STL that's a very common 3D format. You can render it on Blender or any other 3D program.

Sometimes I also load those 2D designs on OpenSCAD. OpenSCAD let you import any DXF 2D CAD file and mathematically extrude, transform, change color, move, join, split the part or do whatever you need with it.

You can also use it directly, without importing the 2D CAD OpenSCAD - The Programmers Solid 3D CAD Modeller

As example to draw a cube in OpenSCAD you just type "cube([2,2,2])".

This is an example piece I made in 2 minutes on OpenSCAD - a motor horn to attach a wheel to a DC motor.

The rendering is in low res to make it render quicker, but the STL export of this piece is a perfect cylinder.

This can be loaded in PyCAM to get it done in a mill or look for a STL to GCODE coverter to be done in a lathe.

An example of LibreCAD 2D to 3D conversion on OpenSCAM would be my hexapod. Each piece is a separate 2D CAD design loaded on OpenSCAD to put it together.

Once you have the STL you can also load it on a 3D program to do some camera travels or animations.

Here it goes a tiny low-res example of a traveling on the hexapod. It was made from the OpenSCAD generated STL on Blender.

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RE: Is it possible to design 3D woodturning projects with CAD on a Raspberry Pi

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All those programs, LibreCAD, Inkscape, PyCAM, PyCAD, OpenSCAD and even Blender could be made to work on the Raspberry but I don't recommend it at all.

Most of them can run on Windows as well. All of them are free.

You want a quick and good PC to make 3D design, raspberry it's not what you really need.

My recommendation is to take some time to learn a bit of 3D and 2D - start with the former - design. It have a quite step learning curve, but the rewards are huge.

Most people here have worked with some type of CAD program - such as EagleCAD - for PCB design. I am sure most of them will tell you the hardest part is the start, but It was worth every minute of their effort.

I am not a professional and I dedicated very few time to learn CAD and CAM processing.

I got some good results so far, and from my experience the hard part is just the start. Once you get the gist of one CAD program, you would be able to work in most of  them.

Most of my work related to 2D and 3D CAD CAM was to use the designs on a CNC machine. If It were not for the CNC machining part, may be I would have not done so much effor.

I always start my designs with pen and paper anyway.

Hope this helps.

Edit: after watching the demos of the software you posted looks like it's really easy to use. It does the 2 1/2 CAD modeling in vertical and mirroring, the results look quite nice. A pity it just let you export it as 3D or 2D image. Exporting to STL this tool would be really useful.

Craig,

If your interest is only in wood turning, you do not need 3D software.

It would be nice, but it is not needed. Because all the parts that you make are created

by rotation around a fixed axle, you only need to create a cross-section of the piece you need,

and that is only 2D.

Just my $0.02,

Jean-Paul (AC9GH)

Hi again Craig.

Thanks to bring this up here. I have been fiddling with the way the program you posted do things and I've found a very easy way to create woodturning - or any lathe machined piece - with inkscape and OpenSCAD that fits quite well in my workflow.

You just need in inkscape to clone one line and mirror it, so any edit you do in the first line, is done in its mirror.

That way the two 2D profiles would be a slice of the part.

https://dl.dropboxusercontent.com/u/88765973/inkscape_woodturn.webm (you need a webm player to watch this video, such as google chrome, opera, firefox browsers or explorer with WebM MF components http://www.webmproject.org/ie/ ).

To finally make a slice, I close the paths just drawing a line between the top ends and bottom ends, and combine them using inkscape tools ( Combine Path and Join Node).

Now I have to export this 2D path to DXF to be imported by other tools. The most compatible way is just to divide the path in as many small lines as possible, because basic shapes are easily recognized among different tools.

For this just use two Inkscape tools Extensions > Modify Paths > Add Nodes and after selecting all nodes the toolbar button "Make selected segments lines".

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After that I can just export it as DXF.

Once we have that slice the only thing we have to do is to center it in one axis, extrude it a bit so it becomes a 3D part and copy the slice rotating it 360 times, one time for the circumference degrees. Of course we have to move it one degree more in each step to complete 0 to 360 degrees.

This translated to OpenSCAD language would be, as seen on the video below:

width = 531;

for( i = [0:360] ){
     rotate(a=[0,i,0]){
          translate([-width/2,0,0])
               linear_extrude(height=4)
                    import("file.dxf");
     }
}

The code on OpenSCAD to do it would be always the same just editing the width of the piece and changing the file name.

In the video and the picture below I took the width of the bottom part, and the top was widder, so to center the piece I used a different translation. In this case -width/3.

But is much easier to just use the part width so it will always be -width/2.

https://dl.dropboxusercontent.com/u/88765973/openscad_woodturn.webm (you need a webm player to watch this video, such as google chrome, opera, firefox browsers or explorer with WebM MF components http://www.webmproject.org/ie/ ).

After that the resulting STL can be loaded in a 3D program such as Blender or SolidWorks, or converted to gcode to make the part in a CNC lathe.

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I would not add more to this thread, because this is sightly out of topic here, as I don't think many people would be interested in 3D design, mills, lathes and routers here. But feel free to send me a private message if you need more information about how to add wood textures to the piece, or any other related topic.

Edit: unfortunately looks like the videos don't work. I have changed the players for a Dropbox link. Will try to convert the videos later.