Modeling binaries with geometry nodes in blender

2026-03-04

Playing around with blender and geometry nodes I made a simple visualization of a black hole orbiting a near Roche filling star. Process is quite fun, geometry nodes allow for easy procedural construction of geometry which allows for some physical accuracy in the representation of such a system. Of course, this is not sourced out of a real simulation, it is meant to be an example that encompasses important aspects of such a system. Background stars are just individual light sources placed far away. Black hole size is far too gigantic but doing it realistically would make it invisible in this scale, and the lensing effect is produced by playing games with a transparent sphere with a weird refraction index. "Oscilations" of the star are constructed from random noise.

But idea here is to highlight some important aspects in such a system. Physical shape of the star is taken from the Roche potential of a binary, and it can be procedurally adjusted to different mass ratios and filling factors. Edges of the star are darkened, as expected. And the "eclipse" produced by the black hole is expected to slightly brighten the source. If you wish to play with this model the blender file is available on zenodo.