Polar Planimeter Quantifies Area By Plotting Perimeter

These days it’s hard to be carry the label “maker” or “hacker” without also being proficient in some kind of CAD- even if the C is for Cardboard. But before there was CAD there was Drafting and its associated arts, and one couldn’t just select a shape and see its area in the square unit of your choice. So how could an old school draftsman figure out the area of complex shapes? [Chris Staecker] introduces us to the polar planimeter, a measuring tool created specifically for the purpose and explained in full in the video below the break.

The polar planimeter being discussed is a higher end unit from the 1960’s. Interestingly, the first polar planimeters were invented in the early 19th century even before the math that describes their function was completed. A lever is placed in a fixed position on one end and into the planimeter on the other. The planimeter itself has another arm with a reticle on it. The unit is zero’d out with a button, and the outline of the shape in question is traced in a clockwise fashion with the reticle.

What makes the polar planimeter capable of measuring in multiple dimensions is the fixed arm. The fixed arm pivots around, allowing the planimeter to track angle changes which affects the output. So, the planimeter isn’t just measuring the length of the perimeter, but the size of the perimeter. The final measurement is output in square inches.

Overall it’s a really slick tool we didn’t know existed, and it’s fascinating to see how such problems were solved before everything could be done with a mouse click or two. Be sure to check out this 100+ year old reference set to round out your knowledge of past knowledge. Thanks to [Zane] for the great tip!

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REMOTICON 2021 // Jay Doscher Proves Tinkercad Isn’t Just For Kids

We invited [Jay Doscher] to give us a view into his process designing 3D printed parts for the impressive array of cyberdecks we’ve covered since 2019.

[Jay] got his start as a maker through woodworking in high school, getting satisfaction from bringing something from idea to reality. After a more recent class in blacksmithing and ax-making showed him what he could do when really focused, his hardware hacking really took off and his line of cyberdecks and other portable computers was born.

If you’ve heard of Tinkercad, you probably think it’s just for kids. While designed as an educational tool, [Jay] found that Autodesk’s younger sibling to the professionally powered (and priced) Fusion 360 had everything needed for making cyberdecks. If you’re willing to work around a few limitations, at the low-low price of free, Tinkercad might be right for you too.

What limitations? To start, Tinkercad is only available in a browser and online. There’s also no guarantee that it will remain free, but [Jay] notes that with its educational focus that is likely to remain the case. There is no library of common components to import while modeling. And, when your model is complete the options for exporting are limited to 2D SVGs and 3D STL, OBJ, and gaming-focused GBL formats. [Jay] has converted those to other formats for laser cutting and the STEP file a machine shop is expecting but admits that it’s something that adds complexity and is an annoyance.

back7-TinkerCad-Alignment

In the talk, [Jay] discusses moving from his initial “cringy” explorations with Tinkercad, to his first cyberdeck, a little history on that term, and the evolution of his craft. It’s mostly a hands-on demo of how to work with Tinkercad, full of tips and tricks for the software itself and implications for 3D printing yourself, assembly, and machining by others.

While quite limited, Tinkercad still allows for boolean operations to join two volumes or the subtraction of one from another. [Jay] does a wonderful job of unpeeling the layers of operations, showing how combinations of “solids” and “holes” generated a complex assembly with pockets, stepped holes for fasteners, and multiple aligned parts for his next cyberdeck. Even if you already have a favorite CAD tool, another approach could expand your mind just like writing software in Strange Programming Languages can.

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The Noble Effort To Put OpenSCAD In The Browser

In a world of CAD packages with arcane or unfriendly interfaces there’s a stand-out player that’s remarkable because it has no interface. OpenSCAD is a CAD package for coders, in which all design elements are created in a scripting language rather than graphically. It’s maybe not for everyone but it has a significant following, and its reach has been extended further as you can now run it from within a modern web browser.

The origins of this project can be tracked back to August of 2021, when when Autodrop3D’s [mmiscool] offered a sizable bounty for anyone willing to port the parametric CAD modeler to web assembly. Developer [Dominick Schroer] ultimately answered the call with openscad-wasm, which implements the core of OpenSCAD as a JavaScript ES6 module. From there, it just needed to get paired with a user interface, and off to the cloud we go.

Opening it up and giving it a go, we found it to be a very usable OpenSCAD version, albeit a little slower to render than the desktop equivalent on a mediocre laptop. We didn’t try exporting and printing an STL, but so far it has given us no reason to believe it wouldn’t be every bit as useful as the version you’re used to.

But wait, there’s more! Parallel to this effort, [Olivier Chafik] has also been working on his own idea of what OpenSCAD in the web should be. He’s using the same core developed by [Dominick], but has combined it with the Monaco editor from Microsoft and a Javascript STL viewer. Despite being very similar, we’re happy to report there’s no rivalry here; in fact, according to the video after the break, it sounds like two the projects have already swapped a bit of code.

The move among desktop applications to move into the browser and often into a pay-to-play cloud has seemed relentless over recent years, so it’s pleasing to see a rare example of a browser migration that’s open-source. It has the handy effect of bringing the CAD package to platforms such as tablets or Chromebooks which wouldn’t normally be an OpenSCAD platform, and this we like, a lot.

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Row of white 3D printed shoes in different styles

CAD Up Some Shoes, But Don’t Start From Scratch

Nothing helps a project get off the ground better than a good set of resources, and that’s what led [DaveMakesStuff] to release his Digital Shoe Design Kit, which is a set of 3D models ready to customize into a basic running shoe.

This is exactly what is needed for people who are interested in designing a custom shoe, but perhaps not interested in modeling every element entirely from scratch. [DaveMakesStuff]’s resources allows one to mix outsoles, midsoles, uppers, and other basic shoe elements into a finished model, ready to be resized or even 3D printed if desired. The files are all in stl format, but resizing stl files is trivial, and more advanced editing is possible with mesh sculpting programs like Blender.

If the gears in your head are starting to turn and you are wondering whether it is feasible to 3D scan your feet for some experiments in DIY custom footwear, take a few minutes and read up on 3D scanning and what to expect from the process to hit the ground running.

CadQuery Comes Of Age

Now, we know what some of you are going to say — “Oh man, not another programmatic CAD tool, what’s wrong with OpenSCAD?” — and you may be right, but maybe hold on a bit and take a look at this one, because we think that it’s now pretty awesome! OpenSCAD is great, we use it all the time round these parts, but it is a bit, you know, weird in places. Then along comes CadQuery, and blows it out of the water ease-of-use and functionality wise. Now, we’ve seen a few mentions of CadQuery over the years, and finally it’s become a full-blown toolset in its own right, complete with a graphical frontend/editor, CQ-editor. No odd dependencies on FreeCAD to be seen! That said, installing FreeCAD is not a bad thing either.

The goal is to have the CadQuery script that produces this object be as close as possible to the English phrase a human would use.

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The Second Worst CAD Package Ever

A while back, [Heavydeck] remembered stumbling across the worst CAD package ever, which is a schematic editor whose existence was purely intended for use to make quick circuit sketches for documentation, presentations and the like. All good. But, being based on low quality JPEG graphics, which when blown up to projector size on a big screen, they look really rough. After deciding that the original nasty, clunky interface was just nasty and clunky enough, [Heavydeck] then proceeded to reimplement the idea over the course of an afternoon, and came up with Kludge (possibly the second worst CAD package ever) making an actually useful tool even more useful.

You see, whether you make website content, YouTube tutorials, or just need to write technical reports, if you’re in the electronics business, you’re going to need to make high-quality editable schematic images at some point, and Kludge might well solve some problems for you. Kludge lets you do so many things; you can save a schematic, you can load a schematic, you can even export it to an SVG file. Actually, that’s all you can do, but it is actually just enough. Once you’ve got an image as an SVG, you can whack that into Inkscape to add some more details and you’re done. We demonstrate this with the image above, which was not annoying at all to create.

So here’s to Kludging your way around a problem, and hoping that the somewhat limited symbol library may expand a little more in the future!

Mechanical Linkage CAD For Everyone

As much as some of us don’t like it, building things for real requires some mechanical component. Maybe it is something as simple as an enclosure or even feet for a PCB, but unless you only write software or play with simulators, you’ll eventually have to build something. It is a slippery slope between drilling holes for a front panel and attempting to build things that move. Sometimes that’s as simple as a hinge and a spring, or maybe it is a full-blown robot articulated arm.  That’s why [RectorSquid] built Linkage, a “program that lets you design and edit a two-dimensional mechanism and then simulate the movement of that mechanism” (that quote is from the documentation.

The program has had a few versions and is currently up past 3.15. To get an idea of the program’s capabilities, the first video below shows an older version simulating a ball lift. The second video shows the actual mechanism built from the design. The associated YouTube channel has more recent videos, too, showing a variety of simulations.

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