A Simple geometry node setup to scatter asteroids instances. I have been using those rocks many times for space and sci-fi pictures.
Updated for Blender 3.1.2 and more.
How to use it:
choose your emit (plane and volume are set by default), starting from a plane of volume is only about the result you want to achieve, the Node tree is the same.
move up the selected squares you want into the Selected_Rocks Collection. They will randomly be scattered on your geometry surface.
If you want instance more frequently than others, duplicate it the appropriate number of times to increase its probability (I am working on a node for this) and add it to the same collection.
Density: number of instances, density is relative to the surface so if you raise or shrink it, the total of instances will follow.
Seed: Change all random values
Min_Scale: Minimum size of instances
Max_Scale: Maximum size of instances
Magnitude: Global scale factor
Scatter: ratio of scattered instances, 0 is none, 1 is full scattering
Distance: length of scattering
About 20 small and medium rocks and three big ones. They all come with UVs but not very good, and a procedural shader with bump.
A Fog Box collection, to add a volume shader to your scene.
Improvements to do:
a probability node by type
a delete by volume function
License: for any use, personnal, educational or commercial.
By Sébastien Garnier, may 2022
Contact, feedback, requests: Anabase.firstname.lastname@example.org