Older articles (3/27)

1. Approximating elliptical arcs in CalculiX Graphics

   The line command in CalculiX Graphics can create lines, arc and splines but not elliptical arcs. This article describes how to approximate elliptical arcs using splines.

2. Hex versus tet meshes in FEA

   In this article the difference in the images of the stresses between a quadrilateral hexahedron (“hex”) mesh and a tetraeder (“tet”) mesh will be investigated. In both cases, second order elements will be used.

   Hopefully this will make it clear to the reader why hex meshes are generally preferred.

   The plate with a hole that was the subject of a previous article will again be used. The analyses will be done using CalculiX.

3. Singularities versus stress concentrations in FEA

   The way FEA works can lead to concentrations of high stress in single elements or even nodes. This article aims to show how such singularities can be recognized and when they can be safely ignored.

4. The titan implosion

   TL;DR, this was a triumph of stupidity and greed over good engineering.

   Engineering design standards are often written in blood, in the sense that these standards often came into being after accidents involving serious loss of life. The CEO of Oceangate ignored them, apparently because they got in his way of saving costs. As it turns out, reality is not susceptible to CEO bullshit.

   Unsurprisingly, “move fast and break things” is not a good strategy when lives are at stake.

5. Testing a Basetech energy monitor 2000

   To monitor the power usage of my electric motorcycle and appliances, I bought a Basetech EM2000. Before using it for real monitoring, I wanted to test it to get a feel for the accuracy

6. No AI training data here

   Recently “generative AI” models have become popular. The term however is a misnomer if not an outright lie.

   There is no “generating” going on, but basically little more than re-hashing of the training materials. This is a rip-off of human creativity, in which I refuse to participate.

   So the license of this website has been changed to include no derivatives and no commercial use.

   Using the content of this website as AI training data is explicitly not allowed.

7. Repairing a USB flash drive

   Recently, one of my USB flash drives, a Kingston DataTraveller 100 G3, stopped working. It didn’t register at all in whatever PC I tried it in. So in this article, I will attempt to repair it.

8. Extracting glyphs from an OpenType file

   In order to create a compact representation of a monogram, I wanted to get the raw curve info from the Latim Modern Roman font, not the rendered glyphs.

   This article documents how I did that.

9. Building vkQuake 1.22.0 on FreeBSD

   The FreeBSD port is relatively old, and doesn’t support SDL 2.2. So I built version 1.22.0, which is current at the time of writing.

   The requirements are the same als the port.

10. From python script to executable with cython

    Recently I saw that you could convert python scripts into executable with the help of cython, and I had to try that.