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Wire Holder

I made a Wire Holder. It’s like a pen holder/pencil cup but for wire of a specific length. It’s difficult to tip it over, especially if you use a high infill. Just visit PrusaPrinters to grab the files for the Wire Holder. (There’s an STL file and an OpenSCAD file available.)

I printed this on my old Monoprice Maker Select Plus, which explains the (poor) print quality. If I had printed it on the Prusa, I’m sure it would look much better. It doesn’t really need to look good though… it works, that’s what matters. (The Prusa was busy printing something more important at the time.)

Also, yes, I know… but this is for wire of a specific length.

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Vinten Tripod Leg Lock

I was doing a video shoot with Ben Nelson for Brown Dog Gadgets last week and I noticed his Vinten tripod leg had an issue staying locked in place… Seems one of the leg lock pieces had broke in half. It seemed liked a perfect reason to fire up OpenSCAD and get the 3D printer spitting out a new part.

In the photo above you can see the new part in silver, and the two original parts on the other legs, in black.

It took two prints to get an acceptable fit. The first was a little too wide and wouldn’t quite fit in place. I tweaked the file just a bit and the second version worked well. I’ll walk through the process a bit below.

For an organic shape like this I usually start by putting it on a desktop scanner to get the profile. This one is curvy, and I’m not big on drawing curves in OpenSCAD, but I am big on scanning in an object and then tracing it in Inkscape. I did a few scans and even then I edited the image a bit to adjust the contrast.

I import the images into Inkscape, each layered directly on top of each other, then add another layer on top of that to do the drawing. I can then easily switch out the image below and compare things. For a symmetrical drawing like this I really just need to draw half of it, then I just dupe and flip to make the other half and combine them into one.

Once I have a vector file created I export that and then import it into an OpenSCAD file where I can extrude it changing it from a 2D shape to a 3D shape. Creating a solid object is the goal. Once I’ve got a solid object I can start knocking holes in it and adding angles by subtracting with various shapes. (The reddish parts are all subtractions or differences from the main piece.)

And yes, the above image does appear to be some sort of special forces TIE Fighter from the Star Wars universe.

Here’s our final piece, ready to be rendered, sliced, and printed. The original part had some pockets on the top and bottom, but since they were not required for functionality I left them out.

Ben installed it and briefly tested it and it seemed to work, though time will tell if it holds up under stress. (Also, this one is PLA so if he leaves the tripod in a hot car, it might soften and fail.) I’ll probably print a few more for him to keep in the tripod bag in case this one does fail in the field.

If you want to print one of these, you can grab the file from Vinten Tripod Leg Lock and have fun!

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STL to SVG

Sometimes I need a 2D vector version of something that is a 3D model. Here’s how I do it. First, if there is an STL file, I load that into OpenSCAD.

For this model I wanted a top view so I could use the hole pattern to laser cut a mounting plate.

I select Show Axes because I’m gonna need that later…

The axes will show the center of the canvas, and luckily our model is centered…

Change the view from Perspective to Orthogonal

If you don’t know the difference between perspective view and orthogonal view, do some research I guess. (I probably learned about them in 7th grade drafting class.) Otherwise, switch between the views and it should make sense…

Okay, next I view the object from the front. Looks good!

I then add the translate command so that I can move the object in 3D space, and I lower it down, in this case 10mm, because the center line is where it will be cut.

The line projection(cut=true) then cuts a slice at the zero point in the Z axis… But we’re not done yet.

(Oh, if you choose cut=false you’ll just get the whole object, not a slice at a specific cross section of it.)

Here we can see what it looks like at an angle, which might make a bit more sense…

Let’s switch from orthogonal back to perspective view… Not required, but I’ll do it anyway.

Back to the top view… and now with the projection you can see the slice we took from the 3D model.

The next step is important… we need to Render the file! You can’t export the SVG file until you render your model.

The model will change… in this case you can see the shapes are now green with red outlines.

And now we can Export as SVG. (You could also use DXF if you need to, though that’s a garbage format I tend to avoid.)

Here’s the SVG open in Inkscape. Brilliant! I can now add to it, and my hole pattern is spaced properly for the mount I want to make. Excellent.

See Also: 3D (STL) to 2D (SVG)

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Ball Feeder Mechanism

Here’s this week’s progress on the wax ball feeder mechanism. These are actually 2D files that were laser cut, but I sort of like the look of making them 2.5D so you can see the dimensionality.

Oh, to make the 3D render I exported a DXF file from Inkscape, load it into OpenSCAD and then use the linear_extrude function.

And yeah, these files are already outdated as there was one mistake (which I fixed with the bandsaw) and I’ve assembled it and found room for improvement.

You can see some earlier iterations here, here, here, here, here, here, and here. Which is to say, if you want to see minor updates with very little context, follow @raster on The Instagram.

You’ll notice an issue with the balls getting stuck in the chute, so there’s a bit of work to do there. I’ve got a few ideas, just need time to test them.

And don’t worry, at some point this might all make sense, once you see the rest of the thing. Or maybe it won’t… who knows!?

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Quick 3D Sketches

stand-01

I’ve found that I prefer firing up OpenSCAD and writing some lines of code to actually trying to sketch simple 3D objects on paper. I grabbed a notepad and thought I could knock out a sketch, but then decided I preferred a model I could spin around and easily edit, and in no time I had what I needed.

stand-02

I’ve found that mocking up cabinets in OpenSCAD works for me. These are not final plans to fabricate something, just quick sketches to communicate ideas with others.