blog.Habrador.com

The one who's running this blog is me, Erik Nordeus. I'm an imagineer (creative engineer) who's interested in the intersection between art and engineering.
This is my portfolio: Habrador.com

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Explaining the Hybrid A Star pathfinding algorithm for selfdriving cars

Let's say you are standing somewhere in a room and would like to find the shortest path to a goal. You can see a few obstacles, such as a table, that you would like to avoid. The easiest way to solve the problem (if you are a computer) is to divide the room into many small squares (cells) and then use the common A* (A Star) search algorithm to find the shortest path. But what if you are a car and can't turn around 360 degrees like a human can, then you have a problem! Well, at least until you learn the Hybrid A Star search algorithm . With that algorithm you will be able to find a drivable path to the goal. The reason I wanted to learn the Hybrid A* algorithm was that I took a class in self-driving cars, where the teacher showed a really cool video with a car that drove around in a maze until it found the goal: The problem was that the teacher didn't explain the Hybrid A* algorithm - he just explained the classic A* algorithm , so I had to figure it out on my own...

How to implement colormaps like Rainbow and Viridis in code

I've been working hard on making my very own digital wind tunnel in the Unity game engine. It's based on a tutorial from the YouTube series 10 Minute Physics called "How to write an Eulerian Fluid Simulator with 200 lines of code." I translated the code from JavaScript to C#, and I open sourced the implementation here: Ten Minute Physics in Unity. To simulate any fluid you need to study the Navier-Stokes equations . These are very hard to solve. In fact so hard they are a part of the Millennium Prize Problems where you can win a million dollars if you gain some insight while solving them. Therefore you need to simplify them. But even though they are simplified you can still see the vortex shedding that's happening in real wind tunnels if you put a cylinder in them. I thought this was really cool because the simulation part is just 200 lines of code running at 70 fps on the CPU. Common colormaps I wanted to improve the wind tunnel by making it more realistic...

Cybertruck Prototype vs Final Production Version - What Changed?

In 2019 I started making a 3D model of the Tesla Cybertruck prototype version in Blender. Four years later, in 2023, Elon Musk finally released the production version of the Cybertruck . Since I've studied every millimeter of the prototype version to be able to make the 3D model I thought it would be interesting to make a comparison of how much changed during the four years. Exterior Front bumper. The black front bumper has become bigger and smoother, most likely to improve the aerodynamics of the vehicle. They also added a mudguard for the front and rear wheels attached to it. Front window. Like the front bumper has become smoother to improve aerodynamics, so has the front window which is now rounded - it used to be completely flat (To be honest I think this is the case anyway - it is not rounded much to make it super visible). Wheels. The wheels are roughly the same as the prototype vehicle wheels - they added som threads to the side of the wheel. I thought t...

How to make a texture atlas template the smart way

Using a texture atlas is a smart way to improve the performance of your game and minimize the number of textures you need to keep track of. A texture atlas is basically a square image you split into smaller squares with the same size. For example, this is how Minecraft's texture atlas looked like in 2011: The boring part is to make the template. I used to create a texture with the size I want the texture atlas to be, like 2048x2048. If I wanted to split it into 8x8 sections, I made a new texture with the size 256x256 with the color black. And then I copied the 256x256 texture into the texture atlas to create a chess pattern. But what if I wanted the texture atlas to be 4096x4096? Then I would have to redo it again! A better way is to first create a tiny image with the size 8x8 (I'm using Paint.Net ). Then you use the Pencil tool with a black color to create a chess pattern: Then you scale the tiny image to the size you want the texture atlas to have: Image → Resize. Set the si...

How to make a Neural Network in Unity in 11 lines of code using C#

Ever wanted to make a Neural Network in Unity using C#? Now you can do that in just eleven lines of code (excluding brackets) using my newly released open source library called MicrogradCSharp . Introduction Neural Networks are the backbone of many modern Artificial Intelligence algorithms and libraries. If you are trying to learn Neural Networks you will notice that most tutorials are made using evil Python code, which is annoying if you like me prefer C# and Unity. A few weeks ago I found a tutorial by Andrej Karpathy who's one of the main characters in the Artifical Intelligence industry. Among others he has worked with Tesla Motor's self-driving cars. The tutorial, The spelled-out intro to neural networks and backpropagation: building micrograd , was about how to build a scalar-valued automatic differentiation (autograd) engine. Why do you need an autograd engine when making Neural Networks? If you have studied Neural Networks you know you have to tr...

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