How To Model A Twisted Part In FreeCAD

Quick references are handy, but sometimes it’s nice to have a process demonstrated from beginning to end. In that spirit, [Darren Stone] created a video demonstrating how to model a twisted part in FreeCAD, showing the entire workflow of creating the part as a blend of surfaces and curves that get turned into a solid.

FreeCAD is organized using the concept of multiple “workbenches” which are each optimized for different tools and operations, and [Darren] walks through doing the same jobs in a few different ways.

This twisted bracket is a simple part that is nevertheless nontrivial from a CAD perspective, and that makes it a good candidate for showing off the different workbenches and tools.

The video below is also pretty good overall demonstration of what designing a part from a mechanical drawing looks like when done in FreeCAD. As for mechanical drawings themselves, we’ve seen FreeCAD can be used to make those, too.

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Analog Test Interface For Your Computer

Wanting to test the response curves on some analog parts, [Don Sauer] devised a way of using simple tools to graph analog tests on a computer. Here you can see the results of testing NPN, PNP, NMOS and PMOS transistors, but modifying the input circuitry would let you test just about anything you want.

[Don] is using an Arduino as the hardware interface. He needed some additional parts, like an op-amp and some passives. Instead of building this on a breadboard, he printed the circuit out on a piece of cardboard, hot glued the components in place, then wired them up. This will let him reuse the interface in the future, but is quicker than designing and etching a PCB.

He uses a Processing sketch to capture the test data streaming in from the Arduino. Once recorded, he uses SciLab to create the graphs. He also covers a method of sifting through the data using Octave, another open source program that feels somewhat like MATLAB.