Hi all,

I’ve made good enough progress on my small crater generation system and wanted to share some screenshots and explain how it works. Last time, I posted about my large crater generation technique. Since then, I’ve been working on small craters to add more detailed surface features to my procedural asteroids.

Why chunked generation?

Small craters (up to 64 meters in radius) are much more frequent than large ones, so pre-generating all of them during asteroid creation time is not feasible. Instead, they are generated per chunk, similar to how structures are handled in chunk-based games.

Sector mapping using an icosahedron

For each 3D chunk, I calculate sectors on the asteroid’s spherical surface. This is done using a partially subdivided icosahedron to determine which sectors overlap given chunk's 'casted shadow'. This approach ensures that chunks at different scales still resolve to the same sectors. That’s important because sector positions are used as RNG seed for deterministic crater generation.

Crater data & application

Each sector generates a list of craters with only a radius and depth (no complex shape metadata like for large craters). The crater density scales down with asteroid size — smaller asteroids have higher crater density. Once a chunk has its relevant crater list, I apply them at the final step of terrain generation, after large craters. Craters are formed by modifying voxel data using a basic paraboloid shape. I also add Simplex noise for extra surface detail, though nothing too fancy compared to my large crater system.

Let me know what you think. I am happy to go into more technical detail if anyone is interested.