This is the personal homepage of Johan Hidding. I'm a PHD student astronomy at the Kapteyn institute at the University of Groningen. My research interests are: cosmic structure formation, the cosmic web, (computational) geometry. In particular I study the Zel'dovich and Adhesion approximations to the formation of the Cosmic Web. My main collaborators are: Rien van de Weijgaert (promotor), Sergei Shandarin, Gert Vegter, and Bernard J.T. Jones. On this page you can find several things either having to do with astronomy or not.


Adhesion model & Computational geometry

In this movie I show how the adhesion model can be computed using a weighted Voronoi tessellation.

Zeldovich Approximation in Blender

The equations describing the Zeldovich approximation are identical to this system in geometric optics. The slab of glass has some minute deformations, which are made visible with a collumnated beam of light and a projection screen. As the slab moves upward, the deformations grow and caustics are formed. This movie was made with Blender and LuxRender.


I've been playing the piano for some time. A few years ago I discovered singing was much more fun. I'm currently singing tenor in the Bragi a-capella choir, vocal ensemble Cantatrix as well as more irregular projects that cross my path.


Allthough I do most of my programming in C++ and Python, I've a dilletante curiosity in more aestheticly pleasing languages like Scheme. At the moment I'm also learning the ins and outs of D, supposed to be C++'s successor. If you have ever done serious C++ coding the way its meant (using STL containers, iterators, standard algorithms and templates) you will know the kind of frustrations that drove people to design D. Recently a majority of C++0x features are supported by the latest GCC compilers, giving some of the power of scheme to C++.

There are some things that I made that could be considered remotely usefull. These are gathered somewhere else.

xkcd - lisp cycles
Last updated september 2th 2013, Contact me at: