Structural fix for detached disk arms. The core problem was that disk
systems generated with inner_radius=0 tried to place near the origin,
but spacing constraints blocked them (core already occupied that space),
creating a visible gap between the core and spiral arms.
Changes:
- Pass core_radius to generate_disk so arms know where the core boundary is
- When inner_radius is 0 (auto), start arms inside the core zone at
40% of core_radius, so the density peak falls inside the core sphere
and arms visually emerge from the core boundary
- Change density exponent from powf(0.62) to powf(0.45) for stronger
concentration near the inner edge (~60% of systems in inner 30% of
the radial span), creating a natural bright-core-to-faint-edge falloff
- Bias randomize_disk toward inner_radius=0 (auto) 70% of the time so
randomized galaxies always have core-anchored arms
francy51
ae7926ecc6