Metaballs are a fun way of creating blobby looking shapes. The idea stems from a method for rendering molecules, where each atom contributes to the overall electron density1. In the easy case of hydrogen, this contribution is a radially symmetric shape centered around the atom’s center $c$: $$ f(v; c) = a \exp(- \|v - c\|_2^2) $$ To render a collection of such atoms, one then takes the sum over these contributions, and renders a level-set:...

16 May 2020 · Konrad Heidler


6 May 2020 · Konrad Heidler

World Population

16 Aug 2019 · Konrad Heidler

Nested Reaction Diffusion

11 Aug 2019 · Konrad Heidler

Brain Volume Rendering

5 Jul 2019 · Konrad Heidler

Soap Bubbles

Have you ever wondered about the rainbows on CDs, gasoline puddles or soap bubbles? All of these have the same cause: The interference of light on thin surfaces. Today, we’ll try to render something that looks like a soap bubble. Some Physics When a ray of light hits the surface of the soap bubble, it is either instantly reflected, or it enters the soap film and is refracted. When it is refracted, it can then be reflected off the other end of the soap, and then leave it again at a slightly different spot....

6 Jun 2019 · Konrad Heidler

3D Reaction Diffusion

2 Apr 2019 · Konrad Heidler

Integration Methods

2 Mar 2019 · Konrad Heidler

Particle Life

Particle Simulations are great. Life Simulations are fun. Meet Particle Life – the intersection of these two worlds. Inspired by Biologist Lynn Margulis’ theory of endosymbiosis, Jeffrey Ventrella invented his Clusters. The main idea is simulating microorganisms that have pretty basic interaction patterns. Some species are drawn towards certain others, while some will be repelled by others. Implementing a particle simulation with these rules leads to very interesting patterns. Compared to physics-based particle simulations, this approach explicitly violates the Conservation of Momentum....

31 Jan 2019 · Konrad Heidler

Reversing Hill Shading in Digital Elevation Models

A while back on the Geographic Information Systems Subreddit I stumbled upon this question. A user wished to get height information from this elevation map they had found somewhere: Unforunately it has hill-shading applied on top of the color bar. While this shading technique makes it easier to understand the terrain structure at a glance, it also makes it harder to extract the raw height data from the map. So first we’ll have to understand how hill-shading works in order to find a way to get around it....

3 Jan 2019 · Konrad Heidler


When I was a kid, I really enjoyed this game called Electroplankton. Especially the game mode called Hanenbow, where you launched small tadpoles onto leaves. On impact the leaves would emit glockenspiel sounds, and create a nice sounding melody. Here’s what it looked like: I wondered, how hard could it be to implement something similar? If you just want to see the animation, click here. If you’re interested in the background, read on!...

25 Dec 2018 · Konrad Heidler


Konrad Heidler