Tag: openscad

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OpenSCAD Viewing Angles

I’ve found that more and more I am exporting images from OpenSCAD, and while in the past I was satisfied with just spinning the object to an angle and exporting a PNG file, I’m now doing more step-by-step things where I want consistency and don’t want things jumping around. Instead of carefully setting the view with the mouse and doing all the exports, I now set the viewing parameters directly in the file, because you can do that in OpenSCAD…

Time to go back to the OpenSCAD User Manual! While the Cheat Sheet is an excellent resource, I find myself hitting up the manual a lot more frequently lately. The Cheat Sheet will show you this of course:

$vpr viewport rotation angles in degrees
$vpt viewport translation
$vpd viewport camera distance
$vpf viewport camera field of view

And that’s what we need! So over to the manual section for $vpr,_$vpt,_$vpf_and_$vpd.

Pop open that Viewport-Control in the Window menu and look at that… it shows you values and you can change them…

(Note: You can also set the aspect ratio, and lock it. Sweet!)

But the real powerful bit is that you can just set those parameters in your code. When you preview your code it will set those values and you get the same viewing angle, rotation, distance and field of view each time. Brilliant!

You can see my commented out code for the bottom versus top view on line 37.

I love finding stuff like this and them implementing it into my code… It’s probably not some amazing killer feature, but it’s one more nicety that helps me keep things consistent and adds a bit more power to what I can do with OpenSCAD.

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Circular Positioning in OpenSCAD

This post is about a problem… it’s about looking at a problem from the wrong angle, and eventually realizing it.

I wrote some code in OpenSCAD, and then I wanted to change something and I could not figure out how to get the positioning right. I should confess I am terrible at maths. In school I took geometry, but never did calculus or trigonometry, and know almost nothing about those areas of mathematics.

Since I tend to work in Cartesian coordinate systems I think about moving things in X and Y. Left, right, up, down… Sure, there are angles, but they can be difficult. But maybe they shouldn’t be…

Here’s what I wanted to do: Create a circle with three smaller circles evenly placed into a triangle. Now typically in OpenSCAD I move things around in the X and Y and for the mostly rectilinear things I design (mostly enclosures) that’s simple, but circles can get weird. So what I tried to do was move each of the holes along the X and Y axes, but I could not get them evenly spaced…

See, this is easy for me. Four things, evenly spaced. Everything moves from the center an equal amount in X and Y. My simple maths brain has no issue with this. I’m so used to doing it this way I can bang it out without any thought. But this way (while simple) is sometimes not ideal.

As is often the case, I took to Mastodon with my problem, because there are people there much smarter than I am… Luckily @GeekAndDad was on the case! While he was busy doing the hard math I was distracted with some other projects… but when I returned I realized I knew how to do it… because I did it ten years ago! Check out this post about Derby Wheels.

Okay, so I did it before, but didn’t have easy access to the code I had written, but remembered how it worked, so I banged this out: 

// Position things in a circular pattern in OpenSCAD

$fn=100;

howMany    = 3;
distance   = 10;
holeSize   = 10;
startAngle = 30;

difference() {

    // create the object
    translate([0,0,0])
        cylinder(d=40, h=3, center=true);

    // loop around in a circle and difference some holes
    for(variable = [startAngle : 360/howMany : 360+startAngle]) {
        rotate([0,0,variable])
            translate([distance,0,0])
                cylinder(d=holeSize, h=3.1, center=true);   
    }
}

(You can also find this code in my gists repository.)

Here we go! Three holes, evenly spaced… We do this by rotating around the center and placing the hole X number of units from the center, every X number of degrees. You can set the number of holes howMany, the distance from the center, and of course the holeSize and also the startAngle which helps rotate the whole set into something that matches up properly.

Hey, you can even do four holes! They are all still evenly spaced from the center…

You can do seven holes… The bit with 360/howMany does the maths to determine how many degrees there are before adding another hole.

Heck, you can even do just two. Want them top and bottom instead of left and right? Just change the startAngle appropriately.

You can put the holes on a square instead… or a rectangle, or anything, really. And they don’t even need to be holes… I just needed holes for this specific example.

Another square with some holes…

And yet another square with some holes… This time with a different startAngle set.

Those holes look a little large… can we make them smaller?

We sure can! Look at that… Obviously you are not limited to just making circles, and this technique of using a for loop to put things around the center of an object can be expanded in many ways. I just wanted to share this recent remembrance so I can find it again when I need it!

By the way, these OpenSCAD renders were all done using my Cyber Night theme for OpenSCAD.

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A 3D Printed Pegboard

Pegboard! It’s the classic way to hang tools in a workshop. Is it the best way? Probably not. It is easy? Sort of. Are there better ways of doing things? Definitely. Anyway, I decided to move forward on this project for a few reasons.

My basement workshop has two large sections of pegboard and a mess of tools. I am in the process of organizing all of those tools, and along the way Kyle Davis was kind enough to mention something called Pegmixer, an OpenSCAD library he had created. I prefer OpenSCAD for my 3D modeling, and once I dug into the library it was much better than the other (quite old) customizable pegboard hanger things I was looking at.

But wait, why the “3D Printed Pegboard” part of this? While you can grab a (nearly) 4 foot by 2 foot pegboard from Lowes for $12 USD, or a nice looking fancy SKÅDIS 30×22″ pegboard from IKEA for more than twice that price, I wanted to try some large prints on the Bambu Lab P1S printer, with a build volume of (almost) 256x256x256mm.

So I grabbed a cheap roll of black Sunlu filament for $14.69 USD and with the help of the openscad-pegboard-peggrid library designed some pegboard.

Now my initial idea was to laser cut some pegboard using this library and all of the scrap 3mm plywood I can get from work, but that also seemed like a silly idea, and with 3mm thickness it would not be compatible with my existing pegboard which is much closer to 5.5mm. By 3D printing the pegboard it would allow me to match it up in thickness to what I already have, so I can move things between them.

I used Pegmixer to create a simple plate that could be used to align the pieces so the spacing of the holes was lined up across sections. Once I put one panel up I then used two plates to align the next one and then screw it into the wall using some drywall screws in the corner holes.

I also printed four spacers for each panel to offset them from the wall. Nothing fancy, just some cylinders with holes large enough for the screw to go through. I ended up gluing them to the back of the panels for ease of installation. I originally had them integrated into the panel but opted to just print them separately.

I know some people will question the logic of 3D printing a pegboard instead of buying one (and cutting it to size) or even laser cutting one. I covered some of the answer in my Printing versus… Not Printing? post. Sometimes cutting things with a saw isn’t easy, or isn’t possible, so printing can be a quieter and much less messy alternative. It can take longer, but it can also happen offline, meaning when you are at work or otherwise busy. For laser cutting a pegboard you need a bunch of flat stock, which (depending on size) may be more costly than a $15 roll of PLA filament. (I did manage to print six panels from one roll, though according to the math I could have got 8 total since each uses 118 grams of filament.)

And yes, I do know about the Honeycomb storage wall that seems to be all the rage, but I opted to stick with the system I already have going. Compatibility and all that.

The 3D printed version (printed face down on a textured plate also looks really nice. Standard pegboard does tend to look a bit ugly. Obviously you can paint it, or with laser cut wood you can stain it, or just buy the IKEA version, but again… it’s all about options. And sure, while it looks good, it is in the most terrible looking room in the house, located in the basement… but I’ve considered adding one to my office as well, where a nice looking pegboard would be more appreciated.

So in the end, I’m really pleased with the look (and functionality) of the new pegboard, and now I need to get back to designing all the things that will attach to it to hold tools and other things!

If (for some reason) you want to use the exact same files I did, you can get the STL and .scad files from Printables.com – Pegboard Panel . Otherwise just grab the library, apply a fix if needed, and do your own thing.

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NIIMBOT D11 Stand

I recently grabbed a NIIMBOT D11 thermal label printer, which is a small/portable device for printing labels. It works well enough (I’m working on a full review for another post) but one of the things that annoyed me is that it cannot stand upright on a desk

For some reason the designers decided that a rounded bottom would be fine, and so it you can lay it down, you can stand it upside down, but you cannot stand it upright, so I fixed that.

This design took a few iterations, and I ended up adding the cutout to use less material, and (hopefully) allow for printing in less time.

This is one of those things I really thought would exist already, but a cursory search yielded no results. So here it is.

As usual, the OpenSCAD file is included if you want to make changes. The BOSL2 library is needed, and this is the first real project I’ve used it on, but it will not be the last.

You can get the STL and .scad file from Printables.com – NIIMBOT D11 Stand. Print it if you need it!

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Fusing 3D Printer Filament

I’ve know about fusing the ends of filament together for at least a decade, but never really tried doing it. Until recently… I tried a few different methods, I did a bunch of reading, watched some videos, and I failed at nearly all of the attempts, or just wasn’t satisfied with the results. But somehow along the way I absorbed enough information to try something, and hey… it worked!

Note: Just want the files? Get them from Printables.

I read a lot of posts, and watched a lot of videos, and I feel that it’s sort of like 3D printing itself – what works for one person may not work for another – so find what works for you and go with that.

The method that is closest to what I did can be found on the Filament Splicer & Joiner with Roll Holder page. Rather than go through all the trouble of printing those parts and assembling it all, I took a simpler approach and went minimal to test things out.

The Tube
I ended up using this PTFE Tube (which is 1.775mm~ ID / 2.5mm OD). Wait, why is this important!? Most PTFE tube used in 3D printers (to feed filament to the machine) is 2.0mm ID / 4.0mm OD. Many methods use this size tube, and the issue is that the filament expands to 2mm inside the tube. The recommendation is to then shave and/or sand down the filament to get it back down to 1.75mm. This method constrains the filament to a dimension much closer to 1.75mm.

Besides the tube (which is the most crucial part of this whole thing) I designed and printed two parts and added a few 3mm bolts and nuts to hold it all together.

You’ll notice a long end and short end of the tube sticking out of the device. You’ll want the short end to be the business end. I probably could have trimmed the tube down on the back side but it’s okay to be a bit longer. Just keep the other end barely sticking out as shown.

I also used a vise to hold the device securely in place (I can see why Turnt use a clamp design) and also grabbed a candle… and of course, some filament!

I’ll try to produce a quality video but in the meantime here’s an illustrated guide demostrating the technique. (And yes, I did mix up the colors as compared to the photos! You also won’t see the vise in the illustrations, so just pretend it’s there.)

Insert a piece of filament from one side and slide it all the way through. It should have a flat cut end on it. This is the piece we will heat up. The other piece (on the right side) should be cut at a 45 degree angle. The angle is primarily to allow you to quickly and easily feed it into the tube without fiddling about.

Put the filament over the candle flame and it should start to soften. Don’t get it too close, or it will catch on fire and burn! Start with the filament further away from the flame and slowly move it closer. I think around 100mm is a good starting point.

Once you see the filament end soften into a blob pull it back into the tube… You’ll need to pull it in about halfway into the device. Practicing a few times will help you get it right.

At this point you may want to move the candle out of the way, or just blow it out for safety.

Once you’ve pulled the heated filament into the tube quickly push the other piece of filament (with the angled end) into the tube.

Now you should be using both hands, holding both pieces of filament, pressing them against each other. Push and hold. You don’t need to push with all your might, but give some good pressure. Wait a bit for it to fuse and then cool… 30 seconds should do it.

Now push/pull the filament out again, and inspect it. Give it a (light to medium) tug to make sure it doesn’t come apart. If it separates, cut the ends and try again.

If you find that you cannot push/pull the filament out of the tube you can loosen the screws to release the clamping on the tube, or separate the top and bottom pieces completely so the tube can be removed from the assembly. This can make it easier to slide the filament out. You will obviously have to slide the tube completely off of the filament piece. When doing this I’ve probably got a spool on one end so I’ll slide the tube away from the spool to free it from the filament and then spool it all up.

Using this method I joined about a dozen pieces of filament into a portion of a spool and then did some test prints. Are they the greatest prints ever? Probably not… Since I mixed multiple colors and brands together I’m sure the filament profile, which should be tuned for a specific filament, sort of goes out the window. Still, the results were completely acceptable and I’d rather find a way to use up all those short bits and unspooled samples I’ve collected over the years.

The Device
You can get the STL and .scad files from Printables.com – Simple Filament Fuser. Print it if you want to give this a try…

You’ll need four 3mm x 14mm (or longer) bolts and four 3mm nuts to assemble the device. You can probably use #4-40 bolts & nuts as well, or adjust the size of things in the .scad file to suit your needs.

If you end up making this and using it, please let me know. Did it work? Did it not work? What was your experience? Any tips or tricks to share?

Update: Don’t like the DIY route? This Filament Welder device is somewhat similar, but reading the reviews suggest you will need to shave/sand down your joints, and you may also benefit from a few of the tips I’ve shared in this post.