This makes it so modifiers are using object transform prior to the rigid body simulation, and then result of modifier stack is fed to the solver. Solves dependency cycle which was happening when object's modifier was dependent on the modifier transform. While now it is not possible to change simulation, things are somewhat more clear and reliable in other ways. For example previously, solver was using derives mesh from a previous step in time, which causes unfixable simulation issues (with intersections and such) Fixex T57589: 2.79 Rigid Body Sim. Does Not Behave The Same In 2.8 Fixex T61256: Compositing scenes causes crash, but rendering separately does not Fixes T61262: Armature and rigid body crash Fixes T61346: Rigid body with modifiers incorrect work