Force field absorption allows dampening of force fields by colliders, but it does not currently work when the scene only contains a rigid body simulation. It requires a particle simulation, cloth, dynamic paint, fluid sim, or softbodies for the feature to work correctly.
The reasons is that the effector function computing force field strength uses depsgraph relations to determine which colliders "absorb" the force field. If there are no dependencies between colliders and effectors registered in the depsgraph, the visibility function `eff_calc_visibility` does not add any absorption.
There is a function build_collision_relations which adds a dependency between the absorption object (the one with a collision modifier) and the forcefield object. It's currently only called by
1. Particle systems (DepsgraphRelationBuilder::add_particle_collision_relations)
2. Cloth, DynPaint, Fluid, and Softbody (DEG_add_collision_relations and indirectly through DEG_add_forcefield_relations).
The `DepsgraphRelationsBuilder` now adds the effector relations also when building rigid body relations.
Pull Request: https://projects.blender.org/blender/blender/pulls/106503
7d8740f06d