Replace mechanicalObject pointer by SOFA Link

[epernod]

Either use : https://github.com/InfinyTech3D/sofa/blob/master/Sofa/framework/Core/src/sofa/core/behavior/SingleStateAccessor.h

meaning you need to inherite from SingleStateAccessor like for example: https://github.com/InfinyTech3D/sofa/blob/master/Sofa/Component/Constraint/Projective/src/sofa/component/constraint/projective/FixedProjectiveConstraint.h

Or you can set your own Link like here:

sofa/Sofa/Component/Mass/src/sofa/component/mass/DiagonalMass.h

Line 119 in 5945d22

SingleLink<DiagonalMass<DataTypes, GeometricalTypes>, sofa::core::behavior::MechanicalState<GeometricalTypes>, BaseLink::FLAG_STOREPATH | BaseLink::FLAG_STRONGLINK> l_geometryState;

[th-skam]

I wonder if these topology/mesh ptrs could also benefit from a SingleLink-style pointer:
https://github.com/sofa-framework/sofa/blob/f8fb655aebc38238fcf68c110c58b2ddc114a8ed/applications/plugins/SofaDistanceGrid/src/SofaDistanceGrid/components/collision/DistanceGridCollisionModel.h#L441-L444

and remove those casts
https://github.com/sofa-framework/sofa/blob/f8fb655aebc38238fcf68c110c58b2ddc114a8ed/applications/plugins/SofaDistanceGrid/src/SofaDistanceGrid/components/collision/DistanceGridCollisionModel.cpp#L464-L467

I see that topology or mesh containers are links in many other SOFA components.